Molecular structure of 2,2'-thiobis(4-methyl-6-tert-butylphenoxy) titanium diisopropoxy. Influence of titanium-sulfur interaction on coordination geometry

被引:82
作者
Porri, L [1 ]
Ripa, A [1 ]
Colombo, P [1 ]
Miano, E [1 ]
Capelli, S [1 ]
Meille, SV [1 ]
机构
[1] POLITECN MILAN,DIPARTIMENTO CHIM,I-20133 MILAN,ITALY
关键词
titanium; 2,2'-thiobisphenoxy ligand; sulfur; sulfide; X-ray structure; Ti-S interaction;
D O I
10.1016/0022-328X(95)06021-N
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The molecular structure of 2,2'-thiobis(4-methyl-6-tert-butylphenoxy) titanium diisopropoxy (la) has been determined, The molecule exists as a dimer, in which the 1,3-dioxadititanacycle is supported by two bridging (i)Pro ligands. The coordination environment about each Ti center is best described as a distorted octahedron, where the S atom and one (i)Pro ligand occupy the axial positions, whilst two terminal phenolate and two bridging (i)Pro ligands occupy the equatorial sites, The eight-membered dioxatitanacycle adopts a symmetric-syn boat conformation, which allows for a significant sulfur-titanium interaction (S-Ti distance 2.724(2) Angstrom). A comparison between these structural features and those reported for the monomeric tetrahedral complexes 2b and 2d, where the sulfur atom is replaced by a methylene bridge in the bisphenoxy ligand, highlights the influence of the S-Ti interaction on coordination geometry, The structural features suggested for 1a to account for the higher catalytic activity of 1a/MAO in polymerization of alpha-olefins as compared with 2a/MAo are clearly demonstrated.
引用
收藏
页码:213 / 217
页数:5
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