| 释义 |
semiquinone Chem.|sɛmɪˈkwɪnəʊn|
[semi- 8 h.]
A molecule or ion derived from a quinone and having one of the two oxygen atoms ionized or bonded to a hydrogen atom.
1931L. Michaelis in Jrnl. Biol. Chem. XCII. 213 The difference between 1 molecule of each of the two successive steps will be proved to be only 1 electron (i.e. hydrogen atom) without any change in molecular size. The intermediary form will in this case be designated as a semiquinone. 1956Nature 10 Mar. 483/1 Alcohols are attacked by photo-excited anthraquinones A* with the production of semiquinones AH. 1973B. J. Hazzard tr. Organicum vi. 380 Since..the semiquinone and p-benzoquinone are not resistant to alkali, the oxidation is carried out in acid solution and then takes place via quinhydrones.
Hence semiˈqui(no)noid a., having or being a structure resembling that of a semiquinone; also absol. as n.
1932Jrnl. Biol. Chem. XCVI. 704 Let us designate the three forms of the substance as R (the reduced form), S (the semiquinoid or intermediary form), and T (the totally oxidized, or quinoid, or holoquinoid form). 1935Chem. Rev. XVI. 265 Among the three constituents of a two-step system it is not always the semiquinoid that exhibits the greatest instability. 1964J. W. Linnett Electronic Struct. Molecules vii. 110 The two members are such that the transfer of one electron from one of the molecules to the other (e.g. from diamine to chloranil) will produce two semiquinonoid-type radicals. |