Today, we're in Revelation chapter 7. We're going to be looking at the entire chapter, and I chose simply to refer to this as the 144,000. So, beginning at verse 1, reading to verse 8. Revelation chapter 7, beginning at verse 1, reading to verse 8. After these things I saw four angels standing at the four corners of the earth, holding the four winds of the earth, that the wind should not blow on the earth, on the sea, or on any tree. Then I saw another angel ascending from the east, having the seal of the living God. And he cried with a loud voice to the four angels, to whom it was granted to harm the earth and the sea, saying, Do not harm the earth, the sea, or the trees, till we have sealed the servants of our God on their foreheads. And I heard the number of those who were sealed, 144,000 of all the tribes of the children of Israel were sealed. Of the tribe of Judah, 12,000 were sealed. Of the tribe of Reuben, 12,000 were sealed. Of the tribe of Gad, 12,000 were sealed. Of the tribe of Asher, 12,000 were sealed. Of the tribe of Napthali, 12,000 were sealed. Of the tribe of Manasseh, of the tribe of Simeon, of the tribe of Levi, of the tribe of Issachar, of the tribe of Zebulun, of the tribe of Joseph, of the tribe of Benjamin, 12,000 were sealed. Now, as we look at this, let me give you a brief introduction, and then we'll move into chapter seven. Let me remind you that chapter six introduced a time in the history of man that is still future. For us, it is still future. And it's a time that is called the tribulation. Now, the tribulation is a seven-year period of time that occurs after the rapture of the church, when Jesus Christ takes the church to be with him, after the rapture of the church and before the return of Jesus Christ. The tribulation is a time of God pouring out his wrath on a world that has rejected the Lord Jesus Christ, and is also the time when Jesus takes back the earth from Satan, who has usurped the authority of Christ. Revelation chapter six gave us a view of what would take place when Jesus began breaking the seals of a scroll, the tidal deed of the earth. As each seal was broken, we saw escalating judgments that began to fall upon the earth. In Revelation chapter six, we see the antichrist revealed, widespread violence breaking out, extreme inflation, war escalated along with spreading famine and pestilence, increasing persecution of believers and martyrdom, the increase of natural disasters, including a mass of earthquake and perhaps meteor showers. We saw that in chapter six as we're going through that chapter. Now, these events that we're looking at that we looked at in chapter six took place in the first three and a half years of the seven-year period called the tribulation, and the result was that it became clear to some that the lamb was behind all of this judgment. The lamb is behind the judgment, and they make it very clear in verse 17 when it said in chapter six, the great day of his wrath has come and who is able to stand. What were they saying in verse 16? They were saying to the mountain and the rocks fall on us and hide us from the face of him who sits on the throne and from the wrath of the lamb. And so you see that this is referred to as the wrath of the lamb. They recognize that it's Jesus or Messiah that is pouring out his wrath. Now that's an interesting thing, and I want to touch that for just a moment, because normally when we think of Jesus we do not associate him with wrath. When we, in the 21st century, and we've been doing this for centuries, when we think of Jesus, we think of him meek and mild. We think of Jesus carrying a lamb over his shoulder with kind of a weak smile in his face. We see him as a lamb, but we see him with a mildness about him. And so it's hard for believers, especially hired for those of us who have experienced the grace of God, to realize that Jesus Christ could actually have such wrath that he pours out in this period of time called tribulation. It's hard. It's hard for the church. We are so soaked in the grace of God that it's difficult for people to even believe for a moment that Jesus actually meek and mild would pour out wrath like we find in Revelation chapter 6. But the problem is, as we forget that, he's not only our Savior, but he is also the judge of the whole earth. Jesus does show his anger. He does in the New Testament. Mark chapter 3, we have an interesting story there. Jesus was in a synagogue. There was a man there, the Bible says, who had a withered hand. He was there in the synagogue along with Jesus Christ. And as the religious leaders are watching Jesus closely, they're watching him. And this is ironic to me, to be honest with you, because Mark makes it very clear that they're watching to see if he's going to do something good. That's what they're doing. They're watching him closely to see if he's going to do something good. When's the last time somebody is watching you? They said, I just know they're going to do something good. If I keep an eye on them, I will bust them doing something good. My mom never said that about me. If I keep watching him, I know he's going to do something good. I'll catch him at it. But that's what took place there. They knew that he was going to do something. They saw this needy, they saw Jesus, and they knew that Jesus was going to do something good. So they watched him closely. And so Mark chapter 3, verses 4 and 5 tells us that Jesus said to them, is it lawful on the Sabbath to do good or to do evil, to save life or to kill? But they kept silent. And when he had looked around at them with anger, being grieved by the hardness of their hearts, he said to the man, stretch out your hand. And he stretched it out, and his hand was restored as whole as the other. He looked around at them how? With anger. Jesus did show anger. You say, well, yeah. Remember in John chapter 2, remember how the Lord Jesus Christ is the beginning of his ministry and Jesus enters into the temple? And there are the money changers and all. There are the people who are ripping off the pilgrims. It's very interesting how that Jesus is there during the Passover. He does go into that temple. He does see those money changers. He sees the people selling animals. And what does he do? It was pointed out by one of our recent speakers that he just began slowly to fashion a whip. He made a whip. That's what it says in John chapter 2. He made a whip of cords. Now, can you picture that? Jesus is watching all that's taking place, and he's getting some cords together, and he's putting it together because he's going to go and drive them out. And he was angry. It says in John chapter 2, verse 16, he said to those who sold doves, take these things away. Do not make my father's house a house of merchandise. And it is mentioned of him that the zeal of the Lord consumed him. Does the Lord Jesus Christ show anger? Yes. Not only did he show anger at the fact that people wanted to leave a man with a withered hand untouched and unhealed, not only did he get upset in the beginning of his ministry when he fashioned that whip of cords, but at the conclusion of his ministry, he once again entered into the temple and once again cleansed it. Mark tells us in chapter 11, verses 15 through 17, they came to Jerusalem. Jesus went into the temple and began to drive out those who bought and sold in the temple and overturned the tables of the money changers and the seats of those who sold doves. He would not allow anyone to carry wares through the temple. Then he taught, saying to them, is it not written, my house shall be called a house of prayer for all nations, but you have made it a den of thieves. He wouldn't allow them to come past him. He stood there as a guard in the temple. So in the next time you begin to think of Jesus meek and mild, Jesus was a bad dude. No, I don't say that disrespectfully. He's the, he's God on earth. I mean, he's corsies. Of course he's powerful. Of course he's got authority. Of course he has that, that presence about him. Of course he does, but sometimes we forget that. You see Revelation six revealed Jesus displaying his wrath. That's what we saw as the lion of the tribe of Judah, but we now enter into chapter seven. Chapter seven is what is called parenthetical. It actually separates the six seal judgment from the seventh seal. The seventh seal isn't resumed until chapter eight verse one. And chapter seven actually is giving to us an answer to the question that was asked in verse 17 when the question was asked, who's able to stand? Who's going to be able to stand when the wrath begins to pour out his judgment? And the answer is going to be those who have found the grace of God through Jesus Christ. What we see in chapter seven is two major groups of saints in the tribulation and we'll look at them. When you look at verses two through eight, you see one set of those who are being referred to. Then when you look at verse nine to the conclusion of the chapter, you see the second. Now in verses two through eight, we have what are called the 144,000. The 144,000 representatives of the godly remnant of Israel are being referred to here. These are the ones that are, they're during the period called tribulation. These believers will survive. They're going to survive the seal judgments, the trumpet judgment, the bowl judgments that are going to come upon the earth. They're going to survive anti Christ persecution, the wars, the famines, the natural disasters, the diseases and all the evil that breaks out. They're going to enter the millennial kingdom alive because as we see they have the seal of God. They are preserved by God. Now you see that in the Old Testament. Noah survived the flood. Lot survived Sodom and Gomorrah. Rahab survived Jericho. There's a remnant that survived the Babylonian captivity. And so these people are those who are going to be passing through. These are people who are going to go and be preserved by the Lord. The second group is found in verses nine through 17. These are the ones who were referred to as tribulation saints. These are those who do not survive the tribulation alive, but they don't experience God's wrath either. They're not coming under his wrath. Some are going to die. They're going to die perhaps during the earthquakes. They may die during the wars and the famines, the disease.  They're not sealed. They're not going to be preserved. They're actually going to go through and die during the tribulation. So do people actually die who are believers during the tribulation? The answer is yes. These are tribulation saints. Notice verse 13 and 14, and we'll get there in a moment, says, one of the elders answered saying to me, who are these irate in white robes and where did they come from?  These are called tribulation saints. We'll look at that group in just a moment. Will anyone be saved after the rapture occurs is a question that people sometimes ask. After the rapture of the church, there will be people placing their faith in Jesus Christ for salvation. Why? Because God's desire to save people continues. Remember with me in the Gospel of Luke chapter nine. Interesting story there. It's found in verses 51 through 56 in Luke chapter nine verses 51 through 56. It says, as the time approached for him to be taken up to heaven, Jesus resolutely set out for Jerusalem and he sent messengers on ahead who went into a Samaritan village to get things ready for him. But the people there did not welcome him because he was heading for Jerusalem. When the disciples James and John saw this, they asked, Lord, do you want us to call fire down from heaven to destroy them? None of us have ever wanted to do that, right?  They were greatly insulted. Why? Jesus's face was set to go to Jerusalem. He is passing through Samaritan village. Samaritans and Jews have no dealings together. Jews normally would cross the Jordan to the east and and skirt it as they went south or cross the Jordan and go north across the Jordan and pass Samaria. And yet these Samaritans would not receive Christ who was about to go through and all. And so the response of his true blue disciples was, let's just smoke them. Can we call fire down from heaven? Jesus turned and rebuked them, went to another village. The Lord is not slack as some encounter slackness, but his long suffered, a long suffering toward to us were not willing that any should perish, but that all should come to repentance. 2 Peter 3 9 God's desire is for all to come to repentance. God's desire is to save people. And during the tribulation, the Holy Spirit continues to work to convict sinners of their need for salvation. Again, I mentioned a moment ago chapter seven has been referred to as a parenthesis. In chapter six, we saw the opening of six of the seven seals on the scroll chapter six, verses one and two introduced to us the antichrist with the break into the first seal, the seven year tribulation period began. Now the tribulation begins with the signing of an agreement between the nation of Israel and the antichrist. Daniel tells us when the clock begins to mark the start of the tribulation. In Daniel chapter nine, verse 27, speaking of antichrist, it says, he will confirm a covenant with many for one seven. In the middle of the seven, he will put an end to sacrifice and offering. And on a wing of the temple, he'll set up an abomination that causes desolation until the end that is decreed is poured out on him. This seven is seven years. This is a seven year period according to Daniel nine 27. And so the tribulation is a seven year period broken into two segments of three and a half years. You have what is called tribulation, which is the first three and a half years. And then Jesus spoke concerning great tribulation, which represents the last three and a half years. You'll see that clearly as we go into some of the further chapters here in Revelation. Again, we looked in chapter six at the opening of the six seals of the scroll. They introduced the tribulation. And this opens the time of call what is called the wrath on earth. The things that we've looked at, according to Matthew 24, eight were the beginning of birth pains. Now we would expect chapter seven to continue with that theme, but it doesn't. You don't pick up with that theme again until chapter eight, verse one. Again, we looked at chapter six, verse 17, where the question was asked, who's able to stand? The answer, of course, is no one. No one is able to stand. No one would be able to stand when God pours out his judgment. If God didn't show mercy and grace in Habakkuk, chapter three, verse two, it says, Lord, I have heard of your fame. I stand in awe of your deeds, oh Lord, renew them in our day, in our time, make them known. Then he goes on to say, in wrath, remember mercy, in wrath, remember mercy. So chapter seven reveals God giving mercy. It's been called the calm before the storm. Verse one, that's all your introduction. We better get into the chapter after these things. I saw four angels standing at the four corners of the earth, holding the four winds of the earth that the wind should not blow on the earth, on the sea, or on any tree. So I saw four angels. These are ministering spirits, and they're actually actually acting out in a merciful way. Now notice these angels are portrayed as restraining the wind, and as they're restraining the wind, it produces an eerie calmness. Nothing is stirring. What happens when the wind begins to be restrained, when they're holding these four winds of the earth and the wind should not blow on the earth? What happens? Well, there's something that is called the hydraulic cycle. It's not raining, there's what happens is there's a drought that is going to take place. And with that drought, there's going to be starvation, there's going to be pollution, because there's no rain. And so what is happening in this calmness is people are given time to think because God is bringing judgment. When it speaks of four corners, there are those who say, see these backwards people actually thought that the world was square, and it had four actual corners. No, that's an old term, even in the Bible times, four corners represents the whole earth. It's not actually four corners, it's just an expression concerning the whole earth at that time. Now, in this case, what we're seeing is judgment being typified with the winds. It says in Jeremiah 49, 36, upon Elam, will I bring the four winds from the four quarters of heaven and will scatter them toward all those winds. And so this is a picture of judgment. He says, I saw in verse two, I saw another angel ascending from the east, having the seal of the living God. And he cried out, he cried with a loud voice to the four angels to whom it was granted to harm the earth and the sea saying, do not harm the earth, the sea, or the trees that we have sealed the servants of our God on their foreheads. So he has the seal of the living God. The seal represents ownership. And it also represents security. The seal that we're looking at here are believers. They are the redeemed and they're being protected by God. Now notice it says he's ascended from the east. We need to remember that Jerusalem would be to the east of Patmos. And so he's possibly saying he's coming from that direction. And the order in verse three is, do not harm the earth, the sea, the trees that we've sealed the servants of our God. So divine protection is given to these servants. Even when facing persecution from the beast, these will be protected by God. And he goes on to say, verse four, I heard the number of those who were sealed. 144,000 of all the tribes of the children of Israel were sealed. Now God is revealed here as being at work within the nation of Israel. And in verses five through eight, he begins to give names of tribes. He speaks of the tribe of Judah, etc. What we need to know at this point is he's speaking concerning the nation of Israel. He is not referring to the church because the church has been raptured. And these 144,000, I'll say this briefly, is not in reference to Jehovah's Witnesses. I have had conversations as perhaps most of you have, which shows the effectiveness of their door to door ministries. Or they actually go door to door and talk to people. I have had conversations with Jehovah's Witnesses and within their own literature, they will tell you that the 144,000 are Jehovah's Witnesses. Is that what the Lord is saying here, that these are Jehovah's Witnesses? No. He gives to us the tribes of Israel and he names 12 tribes. And when I've spoken to Jehovah's Witnesses on this particular matter, I've asked them, which tribe do you come from? Now I'm a Mexican. I come from the tribe of Reuben. Where do you come from? God is at work in the nation of Israel. Let me give you five reasons. I'll say these briefly. God is at work in the nation of Israel. This is the nation of Israel. This is not in reference to the church. Why would God be at work in the nation of Israel? One, it's because God loves the nation of Israel and God keeps his promises. In Genesis 12, one through three, the Lord had said to Abram, leave your country, your people, your father's household, go to the land I will show you. I will make you into a great nation and I will bless you. I will make your name great. You will be a blessing.  Zechariah two eight through ten for this is what the Lord Almighty says after he has honored me and has sent me against the nations that have plundered you for whoever touches you touches the apple of his eye. I will surely raise my hand against them so that their slaves will plunder them. Then you will know that the Lord Almighty has sent me shout and be glad oh daughter of Zion for I am coming and I will live among you declares the Lord. One, God loves the nation of Israel. God keeps his promises. Second, why would this be Israel? Messiah comes from Israel comes from the nation of Israel. Romans one three. Jesus was made of the seed of David according to the flesh. Third, God gave the Bible to the nation of Israel as his revelation. No other people received this word as Israel did in Romans chapter three verses one and two. What advantage then is there in being a Jew or what value is there in circumcision? Much in every way. First of all, they have been entrusted with the very words of God. So God gave the Bible to the nation of Israel, his revelation. Fourth, God was revealed to the rest of the world through Israel. In Romans chapter nine three through five, I could wish that I myself were cursed and cut off from Christ for the sake of my brothers, those of my own race, the people of Israel. There's is the adoption of sons. There's the divine glory, the covenants, the receiving of the law, the temple worship, the promises, the people of Israel. There's is the adoption of sons. There's the divine glory, the covenants, the receiving of the law, the temple worship, and the promises. There's are the patriarchs and from them is traced the human ancestry of Christ who is God over all forever praised. Amen. God was revealed to the rest of the world through Israel. And fifth, God is not through working with the nation of Israel. He's not through. Romans 11, one through five, did God reject his people by no means? I'm an Israelite myself, a descendant of Abraham from the tribe of Benjamin. God did not reject his people whom he foreknew. Don't you know what the scripture says in the passage about Elijah? How he appealed to God against Israel?  I am the only one left. They're trying to kill me. And what was God's answer to him? I've reserved for myself 7000 who have not bound the knee to Baal. So too at the present time there is a remnant chosen by grace. God is not through working with the nation of Israel. Now here we have a list of 12 tribes. Here's something for you. Some will say, how can that be? How can the tribes be known? Well, God has declared in scripture to be all knowing. So I'm going to have to assume that if God is all knowing, he knows who is part of the tribes of Israel. God knows when man doesn't. There are websites right now that you can go on and it's called Jewish genealogical websites and they have what they call deep DNA testing. And if you were interested to see whether or not you had Jewish ancestry, you could actually go on to these websites and you could find out whether or not somewhere in your background you actually have relatives or Jewish heritage. This particular website, as for others, is concerned with and wanting to discover people with Jewish ancestry because they're looking for what in Hebrew it's called the koen, the priests and they're trying to find what are called the koanim, the priesthood. And so they're looking for that in particular because they're trying to line up the lineage of priests. If your name is koen, the koen is the Hebrew word that speaks concerning priests and even to this day when you see people whose last name is koen, that's referring to the fact that they come from a lineage of priests. And so you can go on these websites. They have something called a Sephardic website, Jewish genealogical websites and a variety of those things. And for those of you who are Hispanic, perhaps you may be interested to know that there are many Hispanics who actually derive their ancestry from Israel. And you can find quite a number of Jewish Hispanics in a variety of places, including South America, Central America. Here in the United States, you can go just outside of Santa Fe, New Mexico and there's a good group, a good-sized group of Hispanic Jews. And you may very well have Jewish ancestry within you. I could go into that with you. I'm actually interested in that kind of thing and we've done some personal research on that. But there are people who are greatly interested in that kind of thing at all. So there are people who are actually looking and trying to find people of Jewish ancestry today and they're finding them through deep DNA testing. You can actually know for a fact though that you don't need deep DNA testing. In reality, God knows. And it's interesting, as you see that in 2 Timothy 2 verse 19, it says, nevertheless, God's solid foundation stands firm, sealed with this inscription. The Lord knows those who are His in James 1. This is interesting. In the introduction of the book of James, chapter 1 verse 1, it says, James a servant of God and the Lord Jesus Christ to the 12 tribes scattered among the nation's greetings. So in his mind, the 12 tribes are still in existence and God knows those who are His. Now, when you look at these 12 tribes named here, in his list, two tribes of Israel, Dan and Ephraim are eliminated and they're replaced. You don't see the tribe of Dan and you don't see the tribe of Ephraim. Why is that? Well, the common answer and I think the correct one is very basic is this. These were two tribes that were guilty of idolatry. As a matter of fact, idolatry was as first mentioned in regard to idolatry with the tribe of Dan, but Ephraim was also associated with idolatry. You can look into Deuteronomy chapter 29 verses 18 through 21 and in that portion, this idolatry is strictly forbidden. But when you look in Judges chapter 17 into chapter 18 verse 30, both of these tribes are in the context of idolatry and therefore there are those who would say and I think rightfully so that they're eliminated because they introduced idolatry into the nation of Israel. Now, beginning in verse nine, one, these are the tribes of Israel, literally. These are the ones who are sealed. These are the ones who are going to go through the tribulation and they are going to be unharmed because God protects them. But now you look at a great multitude of Gentiles. Verse nine, after these things I look, behold, a great multitude which no one could number of all nations, tribes, peoples and tongues standing before the throne and before the lamb, clothed with white robes with palm branches in their hands and crying out with loud voice saying salvation belongs to our God who sits on the throne into the lamb and all the angels stood around the throne and the elders and the four living creatures and fell on their faces before the throne and worshiped God saying amen, blessing and glory and wisdom, thanksgiving and honor and power and might be to our God forever and ever amen. Then one of the elders answered saying to me, who are these arrayed in white robes and where did they come from?  Therefore they are before the throne of God, serve him day and night in his temple. He who sits on the throne will dwell among them. They shall neither hunger anymore nor thirst anymore. The sun shall not strike them nor any heat for the lamb who is in the midst of the throne will shepherd them and lead them to living fountains of waters and God will wipe away every tear from their eyes. How sweet is that? Every nation, notice with me please, every tribe, every people and every tongue. These are in reference to Gentiles and notice how they're dressed. They're with white robes. White robes is a picture of righteousness. It's a picture of purity through the cleansing of the blood of Jesus Christ. They have palm branches.  Remember with me when Jesus entered into the city on Palm Sunday and notice also they had songs of praise, Psalm 1491 says praise the Lord, sing to the Lord a new song, his praise in the assembly of the saints. These are people who are worshiping and praising God and I want you to see this with me for just a moment. Notice how it says in verse 11 and they fell on their faces before the throne and worshiped God. Do you think they did that to be seen by men? No. Is there a place for believers to worship God with such intensity? Absolutely. What's the problem sometimes? The problem sometimes is I'm impure and I might do something to be seen by men and not by God. But guess what? In heaven you don't have that problem. In heaven you're not falling down in your face so the person next to you will look at you and say, oh what a very holy worshiper that one is.   It's just you and him and have you ever been overcome by the Spirit of the Lord in that fashion where the Spirit of God is just moving in you in such a righteous way where you go, oh God, you're too much. Have you ever done that? I have. I can't honestly say I have often. I can't say I have enough, but I have. There have been some times in my work where I just cry, where I'll just, it's just Jesus in me, you know, and I just will, I'll just shake my head and I'll just say, oh God, and I'll just say, oh God, you're just so much. You're too much. You've blessed me so much. Thank you Lord. Amen. See this is not, listen guys, this is not something that's weird.  I'm not saying you need to jump around and swing a tambourine around us or, you know, get on a chandelier and swing through the hall. I'm not saying that. I don't think you have to dance around and do weird stuff either. Please, I'm not saying that at all. What I'm saying is true worship. True worship is when you just, if your knees are not on the ground, your heart is. If your face isn't touching the carpet, your heart is before the Lord, before God. Worship is not a boring experience. Singing praise to God is not a boring, it's never been intended to. As a matter of fact, I want you to notice something here. Notice verse 10. It says, crying out with a loud voice. With a loud voice.  But it isn't, it isn't worship. Guess what? I think that heaven's going to be kind of a noisy place. I do. I do. You know, sometimes when you watch the babies, when they're singing songs to God, I don't know if you ever have a chance to do that. But when you, when you see the little ones and they're screaming at the top of their lungs, you know, that is so precious. You know, I suspect that that's pretty much what we'll be doing one of these days. You know, just, my son, David, when he was a little, little boy, maybe four years old, had a little girl down the street that he would play with. Her name was Crystal. And David was a very evangelistic four-year-old. He was the kind of little boy. If you had him in the cart and you were going through the groceries, you know, purchasing groceries and you're going through the line and he was in the cart, he would look at the checker. He did this all the time and he would say to the checker, do you know Jesus? Do you know Jesus?    I can remember when salesmen came to the door one day and knocked on the door and said, little David was standing next to the door and he was only around four years old. And he looked up at the salesman and the man looked down. Hi, little boy. And I happened to be right behind Dave. Hi, little boy. Is your father home? And David looked up at him and he said, yes, do you know Jesus? And the man smiles and says, yes, I do, son. Yes, I do.  Because he wasn't, you know, you can't say that to me. Where do you go to church? Where do you fellowship?  You know, that was David. I remember this little girl named Crystal and David was trying to lead her to Christ. And he's, like I said, four or five years old and he used to ride his bike in the front yard with Crystal. And I remember him saying, Crystal, just say praise the Lord. Just say praise the Lord. And Crystal would say, no. And he said, and I could remember him riding past and she's going, no. And he'd say, no, Crystal, just say, praise the Lord. Praise the Lord. No. And then he said, like this, and he yelled at the top of his lungs. I still remember it's just in my heart forever. He yelled at the top of his lungs, praise the Lord.  I suspect that we're going to fall on our faces before God loudly. I really don't think that we're going to be just kind of like, well, bless you, Jesus, you know, I just don't see that.  This is loud. This is loud praise.  Your music's too loud. No, it's not. It's not. Heaven's going to hurt your ears. It's going to hurt your ears. And they're screaming it out. Salvation belongs to our God who sits on the throne to the lamb. And they're worshiping God.  That's what you call sevenfold praise, blessing, glory, wisdom, thanksgiving, honor, power and might. It all belongs to Him. These are the tribulation saints. These are the ones who are martyred during the tribulation. Out of the nations, they will, they will still be being saved during this time. They're going to give up their lives for their faith in Lord Jesus Christ and they're before the throne and they serve Him there night and day. There's a special place of blessing. There's a place of preeminence. There's a place of honor for them. And what touches me deeply is God will wipe away every tear from their eye. Tenderness, tenderness. I've done that with my own children.  I've done that with my grandbabies where they have cried because of their mean mother.  Can you picture that in your heart? He's going to hold you and rock you.   No more pain, no more sorrow, no more hurt, no more disease, no more death, no more fear, but joy swallowed up in the glory of God. Praise God. That's what the Lord is promising. He will lead them to the fountains of water. He's in the midst of the throne. He will shepherd them. They will neither hunger or thirst. They will not be struck with the sun. There'll be no more heat because Jesus will shepherd them. I bless the Lord for the promise of God to these tribulation saints. They went through something terrible but they'll never cry again and for them I am certain not a single one would ever say that it was not worth it. They will all say it was worth it. It was worth it.


Imagine a world where the physical and digital realities are merged, can coexist, and you can move seamlessly between these worlds. This is the promise and potential of augmented reality. Hello, my name is Parath Rajagopalan and I am the Director of Strategic Marketing at ST Microelectronics. Thank you for viewing the laser beam scanning for augmented reality smart glasses technology demonstration. It's a pleasure to share with you today a brief presentation and demonstration of a very exciting technology which we presented at the CES 2021 virtual event in the ST virtual booth. Before jumping into the technology demonstrator, let me first share with you a quick background or refresher on laser beam scanning technology. This is quite a busy slide and I'll walk through this slowly. So starting at the top left, you'll see an illustration of the operating principles of LBS or laser beam scanning. Quite simply, it combines the pre-modulated light from the three lasers which go through collimating and beam combining lenses onto a MEMS mirror scanner which then performs a rock to scan and the full image is delivered to the eye or any other surface. In the block diagrams below, we show two key aspects of the solution. One is the electronic subsystem and the other is the optical light engine. Now the electronic subsystem includes three key devices from ST which are the MEMS mirror driver, the laser diode driver and a digital controller which provides a closed loop control of the imaging system. This electronic subsystem then connects to the optical light engine in which the key elements or the laser diodes which is developed by our partner and along with ST, laser alliance funding member OSRAM, also included are beam combining optics, some of which is noted above in the illustration of LBS and of course the MEMS micro mirrors provided by ST. Now these are then integrated into a compact PCB shown below which is then coupled into a waveguide and this waveguide is been developed by a partner and also a laser alliance funding member Displex. This PCB is embedded in the temple of the glasses. Now on the right hand side are some of the key characteristics of the laser beams can solutions from ST. Now in addition to multiple technology platforms for the MEMS mirrors including electrostatic, electromagnetic, thin film piezo and including as well high performance laser diode driver as well as a controlled ASICS ST has also developed really optics which optimizes the beam profile onto the coupler of the waveguide. Now in this slide we illustrate over here and you can see the actual glasses that embodies the key technology elements just discussed. The light engine is embedded in the right temple of the glasses. Some people call the temple arm. Now hopefully you can see from this 360 image how laser beams can solutions can lend itself to the creation of stylistic and a very good form factor AR smart glasses. These look nearly like any of the glasses that you can buy in the market. This slide shows several additional images of the technology demonstrator as well as what it looks like when worn. Again you can see the glasses are quite stylish and can be worn anywhere and quite frankly people won't be able to readily distinguish these as AR glasses from regular eyeglasses. Of course this is just a technology demonstrator and I'm sure many of you out there can use LBS technology to create even smaller form factor AR smart glasses. These photos capture the image as seen through the glasses although as many of you know it is difficult to capture images using a CMOS image sensor based camera and then re-display these or map these onto the color palette of models or displays. These images still do show however very good image quality as seen through the glasses. The field of view is more than adequate, the brightness is excellent, the text quality is quite good. Regrettably we're not able to have physical demos this year but I can tell you the images are much better when actually viewed with the eye. Hopefully as noted in the break news we'll be able to meet again in person soon and you can try out these glasses for yourselves. This image shows an example use cases for these glasses as worn and in a live environment. Once again you'll see a rather pleasing form factor and as I mentioned earlier the volume of the size of these can be further reduced. And finally here are some of the key specifications of the demonstrator. Some of the key ones include good, actually that would say more than adequate, field of view of 30-degree diagonal which is more than sufficient for applications that requires to display information and content such as graphics, text overlay, symbols and other informatics. And as I mentioned earlier the brightness is excellent at 1300 nits or candles per square meter which is quite significant as it lends the part to be designed with highly transparent lenses rather than heavy tint in order to achieve high ambient contrast ratio. And the demo clocks in in just under 58 grams of weight which is very important to ensure all the wearability and user comfort. So let me thank you all for your attention. I hope you found this presentation on laser beam scanning for AR smart glasses of interest. And if you have any questions or would like more information please feel free to talk to me, my colleague or our partners at the contact information below. Thank you.


My name is Barnard Kimoro and I work for the State Department for Lifetalk, Minister of Agriculture and Lifetalk Development, where I'm in charge of coordinating policy that looks at adaptation and mitigation measures in the lifetalk subsector for us as a country from the global south. When you look at the agricultural sector as a whole, lifetalk is a very important subsector. Progressively what you have seen is that there has been increase of temperature which is creating a lot of heat stress on lifetalk. So that has a direct impact in terms of reducing productivity from lifetalk. We're also seeing emergence of new diseases and the pests which are further exacerbating the issues around productivity. Further we're also seeing especially in the fragile ecosystems, the increasing frequency and predictable droughts are actually leading to direct losses of lifetalk and that is affecting the livelihoods in those particular areas. Climate change is actually becoming a driver to other issues that traditionally not been there. We're also seeing issues around conflicts because lifetalk now have to go further in the past areas and this is leading to inter-communal conflicts because the resources are coming more scarce. Working with the CJIR has really been very helpful to us. Getting information that can inform new policies that you're forming which are directly looking at focused interventions on adaptation for example climate information services that we need for the species that are adaptable in different areas. Lifetalk species that can actually adapt to the heat stress or even reduced feed materials or even tolerant to some of the pest and diseases. On mitigation of course you also have to look at which technologies can be used to reduce emissions from the lifetalk because lifetalk has been looked at to some extent as one of the contributors of emissions especially methane from material fermentation. When you look at the NDC that we have contributed to as lifetalk sub-sector most of the information that you put there we have used the research especially from ILRI and also our national research systems which are operating. We are looking at a problem which is transboundary. It is taking place across ecosystems. We need to have implementation of interventions which are large scale and for us one of the things we are looking at is how can we be able to mobilize resources and means of implementation that can work at scale. For us therefore at COP27 one of the things we are looking at is can we be able to partner with any organization that looks at addressing climate hazards at transboundary levels and we can be able to ensure that if we are doing an intervention in one area it does not become a maladaptation or create a problem in another area. Increasing population means that we are going to have much more demand of livestock products in the long run. In fact in Kenya we are looking at the milk demand doubling by 2030 and becoming almost three times by 2050. In terms of meat we are looking at almost one and a half times by 2050 so demand is huge we have to be sustainable but we need the means to do that. That will be from large scale implementation initiatives.


In this lecture, we will discuss some of the important organometallic reactions which deal with carbon monoxide. Carbon monoxide is probably one of the most important raw materials that is available to the chemist. It is important that we have some means of converting it into useful chemicals. Because of the small polarity of carbon monoxide, it is not possible to carry out reactions with carbon monoxide, which you can do with carbon dioxide. So, how is carbon monoxide, which is unreactive activated? If you look at the industrial scene, it is clear that there are several reactions such as the water gas shift reaction, the synthesis of acetic acid or even dimethyl carbonate, which is extensively used in CDs in the manufacture of CDs. For example, all of these utilize carbon monoxide as a raw material. So, how exactly does organometallic chemistry succeed in deactivating or deactivating? How exactly does organometallic chemistry succeed in activating this unreactive molecule? If you look at the chemistry that has been developed, you will realize that carbon monoxide has an extensive chemistry that includes alkyl group, aryl groups, alkynes, alkenes and a combination of all of these groups to form useful materials. So, we will consider each one of these initially separately and then we will look at some complicated reactions where multiple groups are involved. So, in all of these reactions, carbon monoxide is activated and it is made possible for a reaction between the unreactive carbon monoxide which is now coordinated to the metal and an alkyl group or an aryl group or a vinyl or allyl group. So, let us take up the first reaction which is probably one of the simplest reactions that is available in this series of chemistry and that belongs to the carbonylation of methanol. This chemistry is that of the carbonylation of methanol where methanol is reacted with carbon monoxide to generate acetic acid. Now, it turns out that if you heat the two under very high pressures, you will not get acetic acid by any means, but the presence of rhodium iodide and methyl iodide as a catalyst. These two are used in catalytic quantities and that is the molar ratios in which you have to do the reaction. So, it is extremely small amounts of rhodium iodide and methyl iodide that are necessary to push the reaction from the left to the right. Why use rhodium iodide? Can we use rhodium chloride or bromide? The answer is no. Actually, it has been shown that H i is essential for driving the reaction from the left to the right. Now, this is strange until you consider the fact that H i actually converts methanol into methyl iodide and that is this reaction that we are talking about right here, which undergoes a simple insertion reaction of methyl iodide with carbon monoxide to give you acetyl iodide. If you add up all three reactions, the hydrolysis of acetyl iodide to give you acetic acid and the two reactions that we just talked about, you will come to the conclusion that you just need to add methanol and carbon monoxide to get acetic acid. So, it turns out that although you need methyl iodide in catalytic quantities and rhodium iodide also, this reaction is an extremely profitable reaction where you have taken two rather unreactive species and converted them into acetic acid, which is such a useful raw material in the industry. Now, let us take a look at the science behind this whole process. Why do we need methyl iodide? Methyl iodide is the one, which will undergo this first step in this reaction where the rhodium diido rhodium carbonate species, which I am marking for you right here, the one that undergoes oxidative addition. You will notice that this is a d h species and it has got a nice filled d orbital that is in the d z squared along the z axis in the d z squared orbital and that is perpendicular to the plane in which the ligands are kept. Now that carries out a nucleophilic substitution reaction on methyl iodide. So, you need a fairly good leaving group for the iodo group to leave from the methyl species. So, that you can achieve this six coordinated compound, which is now d six and it is octahedral in nature and you have rhodium one compound being converted to rhodium three, because you have undergone oxidative addition. This is an oxidative addition reaction and it is now set up to carry out the next step, which is the insertion of carbon monoxide. Now, as we mentioned in the studies in insertion reactions, it is the methyl group, which migrates to the carbon monoxide. So, the methyl group migrates to the carbon monoxide, so that you have an acetyl group coordinated to the rhodium. Now, this whole step is in fact an equilibrium process. This keeps oscillating back and forth, but if you have excess pressure of carbon monoxide, you can drive the reaction to the left side of this catalytic cycle, so much so that you will end up with this compound in solution, which now reductively eliminates. So, it undergoes a reductive elimination. This is rhodium three species and that undergoes reductive elimination to give you the catalytically active R H I 2 C O 2 minus species, which is the resting state of the catalyst. This is the resting state of the catalyst and acetyl iodide is eliminated in the reductive elimination step. So, as we saw earlier, acetyl iodide will be now converted to hydroidic acid and acetic acid. The hydroidic acid is capable of converting the methanol to methyl iodide, which we have pictured here. So, essentially we have converted methanol to acetic acid. So, this step that we have just considered, this catalytic cycle that we have just considered is the simplest of the carbonylation reactions that we would consider today. There is only one oxidative addition and there is an insertion process and a reductive elimination. So, this is an extremely simple catalytic cycle. Now, we will consider a more complex situation, where there are two key steps in the whole reaction and that is the hydro formulation reaction. You will realize that the previous reaction that we discussed was primarily developed by this company Monsanto. Now, we are talking about another chemical company called Rourkemi, which developed this hydro formulation reaction. The person who was primarily responsible for this famous discovery was Otto Roland and he did this as early as 1938. So, you can see that this is long before the renaissance that took place in organometallic chemistry. The discovery of ferrocene, which happened in 1956, but this reaction is an extremely useful reaction, because it converts alkenes in the presence of hydrogen and carbon monoxide to very useful aldehydes. Now, it is possible for this reaction to give you an isomer and we have illustrated this in the second equation that we have written. We have written the hydro formulation of propylene with hydrogen and carbon monoxide. That gives you the normal aldehyde, that is the butary aldehyde and the isobutary aldehyde, which is the isomer, which would be formed if the hydrogen adds on to the terminal carbon and that becomes C H 3. If C H 2, this terminal C H 2 becomes C H 3 and the C H O group, the carbon monoxide is added to the middle carbon in the propene. So, this turns out to be a complication and in fact, the main advantage of the main improvements that have been done in this reaction is the improvement in the selectivity of this whole process. Now, Rowland used dichobalt octacarbonyl as a catalyst. It turns out to be a very efficient catalyst, if you use it at these high temperatures 120 and 170 degrees and with a fairly high pressure of carbon monoxide and hydrogen. So, you will realize that in many of these chemistries that we are going to talk about today, you have to use high pressure of carbon monoxide in order to drive the equilibrium to the right and make the whole situation very favorable and fast. Now, it turns out that this olefin hydro formulation reaction underwent a significant improvement in 1976 and that is the time when Union carbide introduced a catalyst which was based on rhodium. The catalyst that was used by Otto Rowland was on cobalt and that would have given him H C O C O 4. So, the catalyst that was used by him was identical to this species except for the ligands and the metal have been changed. The oxidation state and the electron count are the same for these two complexes. So, H R H C O 2 P P H 3 twice was a catalyst that was used by Union carbide. In fact, they used molten P P H 3 P P H 3 above the melting point of the compound was used in the reaction medium. They found that they could convert the propene to normal butyraldehyde in very good yield. Now, you know that cobalt is 1000 times cheaper and so one has to ask the question why would you use rhodium which is so much more expensive. The answer of course is a fact that rhodium is 1000 times more effective and so it turns out to be more economical in the long run to use rhodium rather than cobalt. The temperatures and pressures are again very high and they have to be kept high in order to drive the reaction to the right. I will write a catalytic cycle now which is based on rhodium but analogous reaction with cobalt can be very easily written. The resting state is again a rhodium 1 compound. Here, we have written a rhodium 1 species as the resting state of the catalyst and the reaction starts with coordination of an olefin to this D H species. Now, we form a co-ordinatively saturated D 10 alkene complex and that is a D 8 alkene complex. Now, you have a hydrogen cis right next to an alkene and the alkene would co-ordinate in such a way that the bulky group will indicate that with. So, the bulky group in fact coordinates closer to the hydrogen. So, that would be the preferred way of coordinating the alkene and the alkene now undergoes insertion reaction. The negatively charged or the formally negatively charged species migrates on to the neutral ligand in such a way that you have now an alkyl rhodium 1 compound. So, you had a hydro alkene complex and after the migration of the hydride you now have an alkyl complex. This again is a rhodium 1 species. So, we have just carried out during the course of this one step a migration reaction which does not change the oxidation state of rhodium. Now, you can in the next step carry out a carbonolation reaction. So, we can add a carbon monoxide to this species to this rhodium 1 alkyl molecule. We can add a carbon monoxide and that gives us a penta coordinate rhodium 1 species which can undergo migratory insertion reaction again. Now, the anionic group is this alkyl group here. So, this alkyl group migrates on to the carbon monoxide and as a result of this migration. So, now you have an acyl complex. So, you have an acyl complex with a vacant coordination site right here vacant coordination site right here. We also have as a result of this migration we have this acyl group and this can add on hydrogen to have an oxidative addition reaction. So, this is the oxidative addition reaction and that happens right here and with oxidative addition of hydrogen you would end up adding two groups in a cis position and this results in the formation of a dihydride that is the final step in this catalytic cycle. You have a dihydride and an acyl moiety and these the acyl moiety is cis to the hydrogen. So, now, you can eliminate this aldehyde. This aldehyde can be eliminated and that is what is coming out in the catalytic cycle right there to regenerate the catalytically active species which is a rhodium one complex. So, this is a reductive elimination step. So, very often a reductive elimination step is the final step in the reaction where your catalytically active species is regenerated. After the regeneration of the catalyst you might have either an oxidative addition or you might have a simple substitution reaction. In this catalytic cycle the oxidative addition and the reductive elimination have happened in the very last two steps. So, a similar catalytic cycle can be written for cobalt only difference would be the fact that H C O C O 4 would be the catalyst instead of the hydridorodium species that we have written right here. Otherwise, all the steps would be extremely similar. Now, the hydro formulation reaction is something that is being actively pursued because it gives us a convenient entry into aldehydes and this has to be done very selectively and also one should note that rhodium is a very expensive metal. So, one normally recovers the rhodium tries to recover the rhodium after the after the reaction and this turns out to be an expensive process also. So, we should also avoid contamination of the product with the catalyst in this case rhodium. It has been said that in some of the expensive catalysts that have been used early processes were so inefficient that the concentration of the catalyst in the product was greater than the concentration of the metal in the ore from which it was initially synthesized. So, this has to be prevented and one has to have efficient means of recovering the catalyst. So, hydro formulation in water was one possible solution to this whole difficulty and company Rhone Poulenc, Rhone Poulenc was a French company which discovered a water soluble rhodium catalyst. Once again the catalyst was the rhodium one species which is the D 8 species which has been described earlier. So, the mechanism of the reaction would be identical except that by introduction of the SO 3 H group the SO 3 H group makes the phosphine water soluble and in turn the phosphine coordinated to the rhodium makes the catalyst water soluble. This is a catalyst which is quite popular and has been abbreviated as TPPTS and it is pictured here. It has got 3 SO 3 H groups which make the compound extremely water soluble and it is usually kept as a sodium salt. The separation of the catalyst is easy because one only has to remove the aldehyde which is usually organic compound soluble and organic solvents. So, it can be extracted and the water containing the catalyst can be recycled. So, hydro formulation in water is one of the means by which one can carry out the reaction efficiently and at the same time save the catalyst and use it for the next step of the reaction. So, in all these cases you notice that the anionic substrate is the one that adds on to the neutral substrate. In this case the neutral substrate is carbon monoxide. It is also possible to carry out the reaction in such a way that the second neutral substrate is also added and then subsequently a reductive elimination is carried out. So, multiple insertions can happen in the catalytic cycle. Example of such a reaction is the Repay reaction. Walter Repay again working in a German company called BASF which is still around and is an extremely old company which used to manufacture unline and soda ash. These chemicals are bulk chemicals which are used in the chemical industry in very large amounts. They discovered some very interesting chemistry which went along with acetylene carbon monoxide and water. You will notice that essentially a molecule of water and carbon monoxide have been added to acetylene in order to generate this very useful acid. So, the reaction was carried out again under high pressure of carbon monoxide. But notice because you are using acetylene this reaction was a great technical challenge to compress acetylene without an explosion was in fact a difficult task to accomplish. It is to the credit of Walter Repay who discovered ways and means of handling acetylene so that it would not explode even when it was pressurized and used in this particular reaction. So, he used it at high temperature at 180 degrees in the presence of nickel bromide and cupricirid as catalyst. He was able to convert acetylene to acrylic acid and in the presence of an alcohol instead of water you can directly convert it into the ester. So, you can either make the ester or the acid depending on whether you use water or an alcohol. So, these reactions were carried out primarily with nickel as a catalyst and cupricirid was just a promoter that was added. If you do the reaction at a higher pressure of carbon monoxide slightly higher pressure of carbon monoxide then the same reaction would undergo a second addition of carbon monoxide and water to this acrylic acid and generate this saturated diacid. So, you can see that the reaction can be an extremely versatile and extremely useful reaction where you can convert acetylene which is again available in bulk quantities to useful organic compounds which are required in the industry for the synthesis of drugs and pharmaceuticals and di-stuffs and so on. So, how exactly does this reaction work? Here is a possible scheme that we have written with nickel and a same reaction scheme can be written for the second step also only the first step is shown here and that too with nickel tetra carbonyl. Nickel tetra carbonyl can lose two molecules of carbon monoxide and undergo oxidative addition to give you this nickel 2 complex. Here nickel is an oxidation state of plus 2 and you have a hydridonical compound which has got this x group which is a group that has to be added. In this particular case you would have to have o r x is o r or it could be o h if you are using water in the reaction medium. So, if you end up having this nickel 2 plus complex which can then coordinate to acetylene. So, the next step is of course coordination of an acetylene molecule and that is what we have here. So, you have an acetylene molecule coordinated to the nickel and you have a hydrogen next to the on the nickel next to the acetylene you can have an insertion reaction. This insertion reaction would give you a vinyl nickel species and that is shown here. A vinyl nickel species where the hydrogen in the cis position has migrated on to the acetylene and that gives you again a nickel 2 species, but now you have to have the nickel 2 species can has carbon monoxide which to which it can migrate to. So, you have a migration of this vinyl group. The vinyl group migrates on to the carbon monoxide which is in the cis position and that gives you the acyl moiety which is pictured here. The acyl moiety can now do a reductive elimination of the two groups the x group and the acyl moiety to give you the product. So, this is your product and this step is your reductive elimination that gives you back nickel 0 which has got only two carbon monoxide and if it oxidatively adds H x which in this particular case it would be the R OH. So, if you start with nickel bromide you can also think of adding the B R and the final step you would have a hydrolysis reaction or an alcohol is reaction. So, because you would have nickel tetra carbonyl is generated from nickel bromide in the in the catalytic cycle. You need only nickel carbonyl, but you can generate it in situ from nickel dibromide and carbon monoxide. So, the rapid catalytic cycle involves an oxidative addition and insertion to insertions in fact an insertion of carbon monoxide insertion of an acetylene and that gives you the required acrylic acid at the end if water is used in the reaction medium. Now, let us take a small detour to heterogeneous catalysis and just mention two important industrially important reactions which have got a lot of relevance to the organometallic chemistry that we are studying. This reaction is actually the water gas shift reaction where water and carbon monoxide is converted to carbon dioxide and the extremely useful energy rich species which is hydrogen. Now, this reaction is normally carried out under heterogeneous conditions. You have a catalyst which is mostly iron supported on copper carbon monoxide and copper and these reactions are surprisingly are difficult to carry out in a homogenous conditions. So, there are practically no homogenous analogs for these heterogeneous reactions. At catalyst like the species that I have indicated here have been used to show that these reactions can be done at least on a small scale or even if they are inefficient they show that such chemistry is in fact feasible. So, the reason why I have chosen these examples is because even though these heterogeneous reactions are really like a black box you do not know what is going on, but still sufficient organometallic chemistry must be going on. There is sufficient organometallic chemistry that is available which shows that these reactions can be mimicked in the homogenous scale also. So, let me give you a catalytic cycle that is possible with the possible catalytic cycle written with iron pentacarbonyl and here if you have iron pentacarbonyl and you have water reacting with it. Let us consider it in two steps with OH minus attacking the carbon monoxide. You can have this OH minus attacking this carbon monoxide to give you COOH coordinated it is an SL a carboxylato anion which is coordinated to the iron and that will have a negative charge because we have added a negatively charged species. We can eliminate from this species the CO2 because you have the right groups with the right connectivity if you eliminate CO2 and if the hydrogen moves on to the iron. So, that would be exactly like a beta hydride elimination. So, you would get an iron hydride species. This iron hydride species that we have written here can react with water and that can generate if it donates a proton. If it donates a proton here essentially this water is for donating a proton. Then you would get a di hydride this is a di hydride that we have here with the iron which can eliminate di hydrogen which can eliminate di hydrogen to give you iron pentacarbonyl back. So, this is a simple catalytic cycle that demonstrates the water gas shift reaction. Although on an industrial scale this is not efficient. So, you still people still use the heterogeneous catalyst for this reaction although there is a homogeneous analog which is available although inefficient. So, what we have done is we have done the reverse of the you have done in insertion on the carbon monoxide which has given as a hydride species and that hydride species gets protonated in this step with water and di hydrogen is eliminated in order to get you the iron pentacarbonyl back. So, the next reaction that I want to discuss is a fissure tropes process which is again an extremely important process which is in fact the key energy source for some countries especially South Africa where there is a plant which is called the sassol plant which converts carbon monoxide and hydrogen to alkenes to products which are like the petroleum products which are alkenes and alkenes and sometimes some oxygenated products are also there like alcohols and aldehydes. Now, the question is how does this reaction work? Now, carbon monoxide is reacted in the presence of a metal surface and so it is easy to imagine the metal surface as reacting with carbon monoxide to generate metal carbonyl species which can be reacted with hydrogen and it might get converted to a methylene species and these species can couple. So, this is shown here in a pictorial fashion, but essentially what we are saying is that the metal carbonyl can undergo hydrogenation reactions or the activated hydrogen which is like a hydride can undergo migration reactions and eventually generate metal carbines. These carbines can couple as we have shown here if two carbines are close together then they can couple and the couple product can undergo an insertion reaction. Here is an insertion reaction and here is a coupling reaction reaction. These are steps which we are repeatedly encountering in carbon monoxide chemistry and this is the kind of chemistry must that must be going on on the surface of the heterogeneous catalyst and this heterogeneous catalyst is a one that is efficient in generating the petroleum products. So, suffice it to say that heterogeneous catalysis is very efficient and it cannot be supplanted by organometallic chemistry completely, but there are sufficient enlightenment on what is going on inside the heterogeneous catalyst by studying organometallic chemistry. Now, let us go back to the carbon relation reactions that we were discussing. Now, we will talk about a palladium promoted carbon relation reaction. Now, these are extremely useful in the laboratory and I have shown for you a reaction which can generate a kumarine and kumarines and isocumarines are synthesized very efficiently in the laboratory using this palladium promoted. This is catalyzed by palladium and usually palladium in the zero oxidation state is what is the resting state of the catalyst, but it is generated in situ in the presence of carbon monoxide. Carbon monoxide efficiently reduces palladium 2 to palladium 0. So, palladium 0 is an actual resting state of the catalyst. It is interesting that a variety of nucleophiles can be used what we have written as N U H can be anything from alcohols or amines and this R X is could be a variety of groups. It could be vinyl, aryl and the insertion reactions can happen very efficiently with as even complicated molecules as the one that is shown here. Let us write the catalytic cycle now to see how exactly this reaction can proceed. So, here is the reaction where you have palladium 0 as the resting state of the catalyst and that can readily do an oxidative addition reaction. So, palladium goes to palladium plus 2. This is palladium plus 2 the formal oxidation state and it has got the R and X groups attached to the palladium which can now undergo an insertion reaction. So, for the insertion reaction migratory insertion reaction to happen we initially add a carbon monoxide ligand and generate this species active species where the R group migrates on to the carbon monoxide. Once the R group migrates to the carbon monoxide you have an acyl moiety. This acyl moiety is attached to the attached to the X group which came from the R X. Now instead of doing a reductive elimination we can have an attack by the nucleophile which we have which we want to react R X with. So, if the nucleophile attacks the carbon monoxide the CO group of the acyl moiety. So, that is the CO group if the nucleophile attacks here you can end up with R CO N U and the N U H will give the proton to the palladium. So, this ends up generating a species which has got a hydrido palladium X group. This can eliminate H X and you regenerate palladium 0. So, this reaction is a simple reaction also. It involves an oxidative addition. So, that is this step an oxidative addition and a reductive elimination in the last step. So, the oxidative addition in fact happens between R and X. So, X has to be a good leaving group. This has to be a good leaving group and the nucleophile has to be a better nucleophile than the X group which is coming out as H X. So, as long as these conditions are satisfied and this condition is satisfied for a variety of nucleophiles. If you have a halide and an amine which is coming in then you have no problem and the triethylamine is basically a base which mops up the H X that is generated. So, at the end of the reaction E T 3 N H plus is liberated or rather the H plus that is liberated is taken up as a is converted into this N E T 3 H plus salt X minus salt and that is removed from the reaction sphere. So, you could have a direct attack of the A cell group with a nucleophile. The nucleophile can also coordinate prior to the reaction to the palladium before the attack on the A cell group. So, these two possibilities are there. Another reagent which is useful in the laboratory is called Coleman's reagent because Coleman developed it to a great extent and this is nothing but the reaction of iron pentacarbonyl with sodium, but sodium by itself does not react with iron pentacarbonyl. But if you react it with in the presence of benzophenone, benzophenone is like a catalyst because it generates the ketyl radical anion and this radical anion is capable of transferring the electron to iron and that results in the tetracarbonylate di anion iron tetracarbonylate di anion which is called Coleman's reagent. So, this is the Coleman's reagent that we are talking about and its chemistry has been extensively studied because it is such a nucleophilic species. It has got a lot of electron density on the iron, lot of electron density on the iron. It can carry out nucleophilic attacks on many, many electrophilic organic compounds which are electrophiles. Here, we have shown two possibilities. One is R X and that will give you an alkyl ferrate, carbonylate species. Alkyl iron is a very high level carbonylate species or an acyl carbonylate species. So, it is also possible to convert this alkyl carbonylate species with addition of either a ligand or P P H 3 or carbon monoxide itself to the acyl carbonylate species. So, you can generate this acyl carbonylate species very efficiently. This carbonylate species which is nothing but the R group with an added carbon monoxide can undergo another reaction with another electrophile. Here, we have shown the reaction with R X. That gives you a ketone. This gives you a ketone. So, starting with R X, you have converted it into a ketone or to an acid by reaction with oxygen. In that case, the iron carbonylate anion is decomposed directly. Now, you can also treat it with an acid. If you treat it with an acid, you generate an aldehyde. As in the previous case, you can also react it with a good nucleophile to generate R C O N U. So, you will notice that along with addition of a nucleophile, you have managed to introduce a carbon monoxide into the molecule. So, Coleman's reagent turns out to be a useful reagent for synthesizing laboratory scale chemicals easily. I emphasize the fact that it is a laboratory reagent, not an industrial reagent because one has to use a very expensive material in order to generate the Coleman's reagent. So, you have to use sodium and refluxing dioxin in order to generate the Coleman's reagent. Now, let us take a look at an example where we have converted an organic bromide into a cyclic molecule using Coleman's reagent. Just to illustrate the chemistry that is behind this whole process, suppose you take this homo-alylic bromide, you have if the bromine was here, then we would have called it an allylic bromide, but this homo-alylic bromide you have an extra C H 2 group. If you treat that with the iron carbonylate species, you end up with this molecule, which is identical to this compound, although we have written arrow here. So, these two things are identical. I have written the carbon monoxide separately. I have indicated the carbon monoxide separately because we are now going to do a migratory insertion reaction. Now, because it is a super nucleophile, it did a simple SN 2 substitution on this carbon. So, first we did an SN 2 substitution on this carbon, got the iron attached to the organic moiety. Now, this is an anionic alkyl group, which is going to do a migration on to the carbon monoxide. So, if it does a migration to the carbon monoxide, you end up with an acyl species. This acyl species is also an anion. Remember, we started out with the di anion, F E C O 4 2 minus and we eliminated bromide. So, we are left with the mono anion that can still undergo another addition of carbon monoxide. This gives us back iron tetra carbonyl acyl species. Now, notice that this species now has got an acyl group and this is the negatively charged group that is there, which I have colored in red. That can undergo a migratory insertion. This time the migratory insertion happens on to an olefin. Earlier, we are doing just insertion reactions on carbon monoxides or in some cases, we have of course, done it on an alkyne. Now, here we are doing it on an alkene and as a result, the iron will be attached to the second carbon atom. So, this is carbon atom 1, this is carbon atom 2 and the iron will be found on the second carbon atom and the migrating group is found on the first carbon atom of the alkene. So, this species, which is a carbonate anion can in fact get get attached to a proton and then undergo a reductive elimination step. So, this is the last step is in fact a reductive elimination which will give you in this particular case a fairly simple molecule, but you can imagine the synthesis of a more complex structure, where pentanone is needed and that can be constructed with this chemistry with the Coleman's reagent. So, you have a series of migrations and insertion reaction of a carbon monoxide in order to generate this cyclic structure. That reaction can also be done with instead of having an alkyl bromide, it can also be done on an epoxide. Now, here I have shown you another metal, which is capable of carrying out this kind of chemistry and instead of the cobalt instead of the iron dianion. Now, we have a sodium cobaltate tetra carbonyl cobaltate, which is going to carry out this nucleophilic attack at this position and that opens up the ring as an anion, as an O minus species here. In this reaction, you have this neutral group carbon monoxide and an alkyl species, which I have marked and read for you. This alkyl species can migrate to one of the carbon monoxide, which is present on the cobaltate. If it does that and adds on a carbon monoxide, we have put we have included two steps here. One is the migration of the alkyl group and the other is addition of carbon monoxide. So, addition of carbon monoxide and migration gives you this new compound, which has got O minus attached to an acyl moiety, which is attached to the cobaltate.  So, this tells you how useful this reaction can be. You have attack of nucleophilic organometallic agent on epoxides, halides and esters and so on. So, up to now we have not considered the coupling of two neutral ligands. In the subsequent reaction, we are going to look at how two neutral ligands can be coupled in an oxidative fashion.  We have discussed the coupling of two acetylene fragments on a cobalt cobalt system, cobalt 1 to give us a cobalt 3 oxidatively coupled cobalt 3 species. So, this is going to be a very similar reaction. So, what we have is an oxidative coupling reaction and here is a reaction, which is called the Poisson-Kahn reaction, where an acetylene, an alkene and carbon monoxide are mixed together in order to generate a cyclopentenone. The previous reaction in one of the previous reactions, we considered the generation of a pentanone and here the saturated form, here it is a cyclopentenone that is generated in this reaction. The important thing is that it is a single step, single step one pot reaction that is carried out with carbon monoxide, dichobold octacarbonyl and two organic compounds. One is an alkene, the other is an alkyne and you end up converting all three species in one step into a cyclic pentenone and that is what we have here. In order to just show you how the reaction can be done with more complex molecules, I have shown you norbonine here as an alkene. So, because it is a dinuclear species, we can imagine the dinuclear species CO 2, CO 8 losing two carbon monoxides and complexing with the alkene and the alkyne, one cobalt complexing to an alkene, the other complexing to an alkyne and if you do an oxidative coupling now, now you have a cobalt zero species to start with and after the oxidative coupling, each of these metal centers would increase the oxidation state by one unit and you would get a cobalt one cluster where two cobalt one centers are adjacent to one another and this dimetallacyclohexene, which is what we have here can introduce or can insert a carbon monoxide. So, this can insert a carbon monoxide plus CO that can give you new species, which is actually a heptanone, a dimetalloheptanone, which can reductively eliminate. Now, reductive elimination gives us this complex structure, which has been stitched together in the coordination sphere of the metal. So, you can see how fairly complex reactions can be carried out in a one part reaction. Now, it is been possible to carry out this reaction because only because the metal is capable of changing its oxidation state to plus one and also because the two metal centers are close enough together to stitch together these two dissimilar fragments. Now, it has been shown for in the case of acetylenes, which has substituted with only one in one one side that they can be combined with simple acetylene to give you an aromatic ring. So, this aromatic ring can also be generated in the presence of cobalt di carbonyl and in this case it people have been fortunate to isolate and characterize the intermediate that is being formed and this is called a flyover complex. This flyover complex is basically having the three acetylene moieties attached together on the di cobalt species. The di cobalt species is coordinated to three allylic fragments, two allylic fragments with three carbons each and you can see that this R group and this R group are coming from the two acetylenes, which we have used and the central acetylene is we will mark it here with a different color. So, that you can see it. So, this is the central acetylene that has been added and that is the central acetylene that we have added and the two other substituted acetylenes are bearing the R groups and they are attached in such a way that they are as far away as possible from the central cobalt cluster. So, they will not be sterically congested, but now reductive elimination from this di allyl unit generates the arene selectively. So, you can combine alkenes and alkynes or two alkynes together along with carbon monoxide. In fact, if you treat iron pentacarbonyl with acetylene, simple acetylene if you treat it with simple acetylene and carbon monoxide it is possible to achieve the synthesis of a quinone, which is now coordinated to iron tricarbonyl. So, you can generate this molecule in the coordination sphere simply by stitching together two acetylenes and carbon monoxide, two insertions oxidative coupling of two acetylenes together and sequential insertions of carbon monoxide will give you this quinone, which is coordinated to iron tricarbonyl. So, we will end with this last example, which is the Dutz reaction. The Dutz reaction involves the combination of vinyl carbene and an acetylene. Vinyl carbene acetylene can be combined together along with carbon monoxide to give you this fairly complicated ring structure. This is a good example, which tells you that very complex chemistries can be carried out in the coordination sphere of the metal atom. So, we have a mechanism of the Dutz reaction, which is described here. We have acetylene which is coordinated to the chromium in such a fashion that you end up with a reaction, which is very similar to what happened in the metal carbene metathesis chemistry. So, you have the formation of cyclobutene, where there is a chromium on the cyclobutene ring. This now inserts carbon monoxide. That is a key step and that is indicated in green here. The inserted carbon monoxide comes from the coordination sphere of the metal. The added carbon monoxide just fills in vacant coordination sphere. Subsequently, we can do an allylic shift of this group, which is attached here because it is in an allylic position. So, you can see this 1, 2 and 3. That will give you this chromium tetra carbonyl compound, which will result in the formation of this di phenol. On one side, you would have ether because you started out with the ether here. So, that is the group, which is present here. So, these are extremely useful reactions. I will end with a di carbonylation, which was discovered by Periasami. That is again with iron. That can also lead to very interesting molecules, which are pictured here, cyclobutene, diones and so on. The double carbonylation is a reaction, which has rarely been observed. It is a very unique reaction that has been discovered, which use of simple iron pentacarbonyl and cuprous chloride as a catalyst. The reaction can be modified to give a variety of substrates, which are pictured here. One example, one possible intermediate is what I have shown you on this particular screen, where iron, because it can dimerize, it can give you these very interesting species, where two iron centers can be coordinated to the acetylene and sequentially insert carbon monoxide. So, the possible insertion mechanism for the double carbonylation is shown here in the last slide. So, the possibility is endless and anionic species like H, R and A R can insert carbon monoxide. You can have a huge library of reactions built on the insertion of carbon monoxide.