| 释义 |
Kekulé Chem.|ˈkɛkjuːleɪ|
The name of Friedrich August Kekulé (1829–1896), German chemist, used attrib. and in the possessive with reference to a system of structural formulæ devised by him, the principal features of which are the quadrivalency of the carbon atom and the linking of carbon atoms to form chains, and esp. his conception of the benzene molecule as having a closed hexagonal ring of six carbon atoms with alternate double and single bonds between them (later extended to other conjugated cyclic carbon compounds).
1871Jrnl. Chem. Soc. XXIV. 824 The author says that he acknowledges the value of Kekulé's ring formula. 1908A. W. Stewart Rec. Adv. Org. Chem. i. 6 But as they actually existed in isomeric forms, the same was to be expected in benzene, if the Kekulé theory were correct. 1938H. Gilman Org. Chem. I. ii. 57 A further, rather serious objection to the Kekulé formula arose from the difficulty of understanding why, if benzene contains three ordinary double bonds, it is so inferior to the ethylenic hydrocarbons in reactivity. 1951I. L. Finar Org. Chem. I. xx. 408 The difficulty with the Kekulé formula is that it represents benzene with three double bonds, and the oscillation does not account for the difference in behaviour between these and olefinic bonds. Ibid. 409 The Kekulé structures contribute far more to resonance (about 80 per cent.) than do the Dewar structures (about 20 per cent.). 1961L. F. & M. Fieser Adv. Org. Chem. i. 16 The Kekulé theory of structure performed valuable service for half a century before the nature of the Kekulé bond became understood. 1964Cram & Hammond Org. Chem. (ed. 2) xxiii. 543 Two equivalent Kekulé structures may be drawn for this C18H18 hydrocarbon [sc. cyclo-octadecanonaene]. 1972E. Clar Aromatic Sextet vi. 29 The VB theory assumes nine Kekulé structures for triphenylene which are supposed to contribute equally to the ground state. |