From B(C6F5)3 to B(OC6F5)3:: Synthesis of (C6F5)2BOC6F5 and C6F5B(OC6F5)2 and their relative lewis acidity

被引：148

作者：

Britovsek, GJP ^{[1
]}

Ugolotti, J ^{[1
]}

White, AJP ^{[1
]}

机构：

[1] Univ London Imperial Coll Sci Technol & Med, Dept Chem, London SW7 2AY, England

来源：

ORGANOMETALLICS | 2005年 / 24卷 / 07期

基金：

美国海洋和大气管理局;

关键词：

D O I：

10.1021/om049091p

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

The pentafluorophenyl esters of bis(pentafluorophenyl)borinic acid (C6F5)(2)BOC6F5 (2) and pentafluorophenylboronic acid C6F5B(OC6F5)(2) (3) have been prepared and characterized by multinuclear NMR and X-ray analysis. VT NMR studies have shown that restricted rotation around the B-O bond in 2 occurs below 193 K, corresponding to Delta G(not equal) = 35 kJ/mol for this process. This low barrier and the random torsion angles around the B-O bonds observed in the solid state structures of compounds 2, 3, and B(OC6F5)(3) (4) suggest that these torsion angles are not related to p pi-p pi interactions between boron and oxygen, but more likely a consequence of the extensive intermolecular F-pi interactions seen in the solid state structures. The Lewis acidity of 2, 3, and 4 has been compared with B(C6F5)(3) (1), using various Lewis bases. All compounds 1-4 appear to be strong Lewis acids, whereby 4 interacts more strongly with hard bases whereas 1 binds more strongly to softer bases.

引用

页码：1685 / 1691

页数：7