M. Unno, R. Tanaka, Toshie Kuribara
Nov 15, 1997
Citations
0
Influential Citations
5
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
The reaction of dichloro(diethylamino)thexylsilane (thexyl = 1,1,2-trimethylpropyl) with lithium gave 1,2,3-tris(diethylamino)-1,2,3,4-tetrathexylcyclotetrasilane (2) as a mixture of four diastereomers (r-1,t-2,c-3,t-4-2, r-1,t-2,t-3,t-4-2, r-1,t-2,c-3,c-4-2, and r-1,c-2,t-3,t-4-2). The isomers were separated and identified by 1H, 13C, and 29Si NMR, IR, Mass, and UV spectroscopy. The structures of r-1,t-2,c-3,t-4-2, r-1,t-2,t-3,t-4-2, and r-1,t-2,c-3,c-4-2 were confirmed by X-ray crystallography. The Si–Si bond lengths are 2.391(1)—2.499(2) A for r-1,t-2,c-3,t-4-2, 2.389(2)—2.478(1) A for r-1,t-2,t-3,t-4-2, and 2.397(2)—2.485(2) A for r-1,t-2,c-3,t-4-2. In these molecules, there is a significant change in the structures of the Si4 frameworks; the dihedral angles were 18° for r-1,t-2,c-3,t-4-2, 34° for r-1,t-2,t-3,t-4-2, and 3° for r-1,t-2,c-3,t-4-2. The chlorodeamination or bromodeamination of 2 with HCl or HBr afforded 1,2,3-trichloro-1,2,3,4-tetrathexylcyclotetrasilane or 1,2,3-tribromo-1,2,3,4-tetrathe...