porphyrinn.
/ˈpɔːf(ᵻ)rɪn/, U.S. /ˈpɔrfərən/ Chemistry.
Any of a large class of deep-red or purple fluorescent crystalline pigments that are substituted derivatives of porphin, many of which occur widely in nature, both in the free state and as complexes with metals (e.g. in haem).
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the world > life > biology > substance > pigment > [noun] > unspecified pigments > purple
porphyrin1910
protoporphyrin1925
porphin1926
1910 Jrnl. Chem. Soc. 98 i. 127 The phyllins are converted by acids into the corresponding porphyrins, compounds which do not contain magnesium.
1931 Sci. Monthly Feb. 192/1 The porphyrine (the iron and chlorine free part) of hemin consists of four pyrrolnuclei..each consisting of a ring structure containing 4 carbon atoms and 1 nitrogen.
1939 Thorpe's Dict. Appl. Chem. (ed. 4) III. 82/2 Porphin and the porphyrins..possess a characteristic type of absorption spectrum, and the power to form stable derivatives with metals, in which the two imino-hydrogen atoms are substituted, e.g. by a divalent metal atom.
1974 Sci. Amer. Dec. 73/1 In chlorophyll the central cavity of the ring is occupied by a magnesium atom... Porphyrin rings in the blood protein hemoglobin and in the cytochromes contain an atom of iron instead.
1993 Guardian 24 Aug. ii. 15/1 Porphyrins are the pigments in chlorophyll and haemoglobin, and his work in this field was briefly in the limelight in 1968 when he suggested that George III suffered from an inherited abnormality of porphyrin metabolism, which caused his psychotic behaviour.
2005 Appl. Catalysis A. 280 86/1 The use of bimetallic catalysts and more complicated ligand-systems like porphyrines resulted in..recent process improvements.
This entry has been updated (OED Third Edition, December 2006; most recently modified version published online March 2022).
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