三环己基羧酸锡的分子结构和晶体结构

用单晶X射线衍射技术测定了三个三环己基羧酸锡化合物—三环己基丁酸锡(1), 三环己基-间氯代苯甲酸锡(2), 三环己基-间溴代苯甲酸锡(3)的分子和晶体结构. 三种化合物均属正交晶系, 空间群分别为P212121(1), Pnaa(2), Pnaa(3). 1的晶胞参数为:a=9.963(2), b=11.004(3), c=20.144(6)埃, Z=4. 2的晶胞参数为: a=8.135(2),b=16.716(3), c=36.426(6)埃, Z=8. 3的昌胞参数为: a=8.165(1), b=16.714(3),c=36.710(4)埃, Z=8. 在1的晶体中, 锡原子呈五配位的三角双锥构型. 桥联的羧基使其结构成为含有两种不同Sn-O键(2.198(4)和2.427(3)埃)的线型聚合物. 2和3的晶体则是由孤立的分子所组成. 在每个分子中, 四配位的锡原子呈畸变的四面体构型, 羧基不能象在化合物1中那样在锡原子之间成桥, 可能主要是由于环己基与卤代苯甲酸根之间的空间位阻效应所致.

The crystal and molecular structures of tricyclohexyltin carboxylates

The crystal and mol. structures of tricyclohexyltin butyrate (I), tricyclohexyltin m-chlorobenzoate (II), and tricyclohexyltin m-bromobenzoate (III) were determine by a 3-dimensional x-ray method. Crystals of I are orthorhombic, space group P212121, with a 9.963(2), b 11.004(3), c 20.144(6) ? Z = 4; those of II are orthorhombic, space group Pnaa, with a 8.135(2), b 16.716(3), c 36.426(6) ? Z = 8; and those of III are orthorhombic, space group Pnaa, with a 8.165(1), b 16.714(3), c 36.710(4) ? Z =8. In I, the Sn atoms are 5-coordinate in a trigonal bipyramidal structure with a bridging CO group. The resulting structure is a linear polymer containing 2 different Sn-O bond lengths of 2.198(4) and 2.427(3) ? In II and III, the structures consist of discrete mols. containing 4-coordinate Sn atoms in a distorted tetrahedral configurations. The bridging CO groups are prevented from approaching the Sn atoms, probably by steric repulsion between the cyclohexyl groups and the halobenzoate.