单词 | porphin |
释义 | porphinn. Chemistry. A purple crystalline solid, C20H14N4, which has a macrocyclic aromatic molecule consisting of four pyrrole rings linked by —CH= groups, and of which the porphyrins are derivatives; (also) a substituted derivative of this, a porphyrin. ΘΚΠ the world > life > biology > substance > pigment > [noun] > unspecified pigments > purple porphyrin1910 protoporphyrin1925 porphin1926 1926 Brit. Chem. Abstr. A. 963/1 The name ‘porphin’ is suggested for the parent substance of (II), containing no β-substituents. 1939 Nature 10 June 967/1 The chlorophyll molecule may be likened to a signet, or rubber stamp, the disk representing a so-called porphine ring. 1966 Q. Rev. Chem. Soc. 20 211 When each of the four pyrrole rings of a porphin bears two different substituents A and B in the β-positions, then four isomers exist. 1973 Jrnl. Amer. Chem. Soc. 95 8506/2 The porphine used in this study was prepared by the acid-catalyzed condensation of pyrrole-2-carbinol in 10% acetic acid-xylene solution. 1984 N. N. Greenwood & A. Earnshaw Chem. of Elements (1986) v. 141 Chlorophylls are complexes of Mg with macrocyclic ligands derived from the parent tetrapyrrole molecule porphin. 1992 C. A. Smith & E. J. Wood Biosynthesis ix. 203 Chemically, porphyrins are complex ring products, with structures comprising four substituted pyrrole units linked together by methene bridges. The basic planar skeleton is termed a porphin. This entry has been updated (OED Third Edition, December 2006; most recently modified version published online March 2022). < |
随便看 |
|
英语词典包含1132095条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。