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Octasilsesquioxane Chemistry I. Attachment of Four Surface Bridges to Octasilsesquioxane Quasi‐cube Framework
Author(s) -
Liu LingKang,
Chu JianeBond,
Slanina Zdenek,
Chow Tahsin J.
Publication year - 2002
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200200133
Subject(s) - chemistry , cube (algebra) , bridging (networking) , ab initio , adduct , stereochemistry , computational chemistry , crystallography , combinatorics , organic chemistry , computer network , mathematics , computer science
The Pt/C catalyzed hydrosilylation of Si 8 O 12 (CH=CH 2 ) 8 and 8 equiv of HSiMe 2 Cl produced Si 8 O 12 (CH 2 CH 2 SiMe 2 Cl) 8 that was de‐hydrochlorinated with 4 equiv of Z ‐HOCH 2 CH 2 =CHCH 2 OH in the presence of excess TMEDA. This preparation resulted in the attachment of four surface bridges (‐CH 2 CH 2 SiMe 2 OCH 2 CH=CHCH 2 OSiMe 2 CH 2 CH 2 ‐ Z ‐) on the quasi‐cube Si 8 O 12 framework. As a parallel study, the theoretical calculations of Si 8 O 12 (‐CH 2 CH 2 SiH 2 OCH 2 CH=HCH 2 OSiH 2 CH 2 CH 2 ‐ Z ‐) 4 were carried out at PM3 semi‐empirical level to find optimized geometries for use in four subsequent ab initio computations using standard basis sets of 3–21G* and 6–31G*. The calculations suggest that one should expect about equimolar mixture of the tetra‐adducts produced by the bridging over the edges of the quasi‐cube, either over four parallel edges or over two orthogonal pairs of parallel edges, but not by bridging across the faces of the quasi‐cube.