Magnesium-containing chlorophyll

Another tetrahydroporphyrin derivative, porphodimethene (7), which consists of two dipyr-rylmethene halves is obtained in the photoreduction of magnesium-containing chlorophyll a (6) with hydrogen sulfide3211 42 as reductant and pyridine as base. 

The most important porphyrin derivatives are characterized by a central metal atom hemin is the iron-containing porphyrin essential to mammalian blood, and chlorophyll is the magnesium-containing porphyrin that catalyzes photosynthesis. Other derivatives include rhe cytochromes, which function in cellular metabolism, and the phthalocyanme group of dyes, Porphyrins are described in considerable detail m a 20-volume set of books, The Porphyrin Handbook, Academic Press, New York, NY, 2003. 

The chlorophylls (types a, b, and c) Green color they are magnesium-containing porphyrins and are technically considered to be mi-crocrystalline waxes... 

Magnesium is an essential element for both plants and animals. Green plants manufacture their own food in the presence of sunlight because plants contain chlorophyll, which itself contains the magnesium ion. Magnesium ions are also required in the replication of DNA... 

Of the wide range of organo-metallic complexes likely to exist in natural waters only a small number have been structurally identified. Two examples of identified complexes found in sea water are cobalt(II)-containing cyanocobalamine or vitamin B,2 (Carlucci, 1970) and magnesium in chlorophyll a (Riley and Chester, 1971). Although a great deal is known about the properties of the unidentified complexes, it is not possible to classify them according to the systematic molecular nomenclature used in classical chemistry (lUPAC, 1973 Cahn, 1974). This undoubtedly has contributed... 

Dark green vegetables such as spinach (magnesium contained in the center of the chlorophyll molecule)... 

Protoporphyrin IX is the starting material for the synthesis of the iron- and magnesium-containing porphyrins of the heme and chlorophyll types. In the formation of chlorophyll a the propionyl side chain of ring C is methylated and a new five-membered ring is formed (protochlorophyllide a). Reduction of ring D and ester formation with phytol (D 6.3) yields chlorophyll a. 

Yes, this is where all the action happens. Iron-based hemoglobin is used in almost all vertebrates, but other creatures use other metals. Most mollusks and some crabs have blood based upon a molecule called hemocyanin, which has copper at its core. Their blood is gray-white to pale yellow in color, but it turns dark blue when they bleed and it s exposed to the oxygen in the air. Some sea cucumbers or sea squirts contain a vanadium-based blood protein called hemovanadin, which turns a mustard-yellow color when exposed to air. Although plants don t have a bloodstream, they contain chlorophyll, which has a structure that is remarkably similar to that of heme, except with magnesium replacing the central iron (see p81). In plants, this molecule is used for photosynthesis - but it s amazing to see how the chemistry of almost identical molecules can be used by plants and animals for very different purposes. 

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