| 释义 |
anchimeric, a. Chem.|æŋkɪˈmɛrɪk, æŋkaɪ-|
[f. Gr. ἄγχι near + µέρος part + -ic.]
anchimeric assistance, the participation of a functional group of a molecule in a reaction at an adjacent site within the same molecule, producing an increase in the reaction rate; also, the kinetic acceleration that results from such an interaction.
1953S. Winstein et al. in Jrnl. Amer. Chem. Soc. LXXV. 148/1 kc is the estimated rate constant of ionization with neither anchimeric assistance nor nucleophilic assistance from solvent. [Note] This adjective (from the Greek ‘anchi’ and ‘meros’), meaning pertaining to the neighboring or adjacent part..has been suggested to us by Dr. A. P. McKinlay..for use in connection with neighboring group participation. 1964Q. Rev. Chem. Soc. XVIII. 45 If the transition state of a rate-determining step is stabilised in this way, an increased reaction rate results and the neighbouring group is then said to provide anchimeric assistance. 1983McQuillin & Baird Alicyclic Chem. (ed. 2) viii. 183 Anchimeric assistance of this kind is clearly geometrically possible for displacement of an exo- but not an endo- group.
So anchiˈmerically adv., by the participation of a neighbouring functional group in the same molecule.
1953Jrnl. Amer. Chem. Soc. LXXV. 148/1 The rate constant of solvolysis with nucleophilic solvent participation exceeds kc more than does the anchimerically assisted ionization rate. 1992Organometallics XI. 292/1 It is uncertain..whether the η5-Cr(CO)3 loss is anchimerically assisted by the migrating species. |