For ten points, identify this class of nitrogenous biological pigments, which when combined with metals form hemoproteins such as cytochromes, chlorophyll, and hemoglobin.
In these molecules, intense absorption at the 400-nanometer Soret band can be seen, as well as smaller peaks called Q bands at around 600 nanometers. Strong bases such as alkoxides can be used to remove the two protons on their inner nitrogen atoms to form a dianion. Due to anisotropic effects from the ring current, the NMR signals for the meso protons on the bridged methine carbons can only be seen in low fields. They obey Huckel's rule, and examples include the prosthetic group for the enzyme that breaks down hydrogen peroxide in the body, catalase. For ten points, identify this class of nitrogenous biological pigments, which when combined with metals form hemoproteins such as cytochromes, chlorophyll, and hemoglobin.
In these molecules, intense absorption at the 400-nanometer Soret band can be seen, as well as smaller peaks called Q bands at around 600 nanometers.
porphyrins