ROLE OF PENTACOORDINATE INTERMEDIATES IN THE HYDROLYSIS REACTION OF ORGANIC SILICATES

被引:43
作者
CORRIU, RJP
GUERIN, C
HENNER, BJL
WANG, Q
机构
[1] Laboratoire “Hétérochlmle et Amlno-acldes”, URA CNRS 1097, Université de Montpellier II, Sciences et Techniques du Languedoc, F-3409S Montpellier Cedex 5, Place E. Bataillon
关键词
D O I
10.1021/om00055a042
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The alcoholysis and hydrolysis reactions of XSi(OR)3, XSi(OR)3 + 10% KOR (X = H, OR), and K[XSi(OR)4] (X = H) or [K,18-crown-6][XSi(OR)4] (X = OR) were studied to approach the mechanism of the reaction. We found the following: (i) The first step of the process in the case of XSi(OR)3 (X = H, OR) was the formation of a pentacoordinate intermediate by nucleophilic activation at silicon. (ii) The rate-determining step was the coordination of R'OH (R/ = H, R) to the pentacoordinate silicon leading to a hexacoordinate intermediate (or transition state), which gave the product. (iii) A step by step nucleophilic substitution occurred on a pentacoordinate silicon derivative, K[H2Si(OR)3] and K[HSi(OR)4], giving another pentacoordinate compound, K[HSi(OR)4] and [K,18-crown-6][Si(OR)5], respectively.
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页码:3200 / 3205
页数:6
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