Electronic interactions in 1-ethynyl-2-phenyltetramethyldisilanes HCCSiMe2SiMe2C6H4X
作者:Jennifer A. Shaw-Taberlet、Jean-René Hamon、Thiery Roisnel、Claude Lapinte、Michaela Flock、Thomas Mitterfellner、Harald Stueger
DOI:10.1016/j.jorganchem.2007.01.024
日期:2007.4
1-Ethynyl-2-phenyltetramethyldisilanes HC=CSiMe2SiMe2C6H4X [X = NMe2 (1), H (2), CH3 (3), Br (4), CF3 (5)] are accessible from ClSiMe2SiMe2Cl, BrMgC6H4X and HC=CMgBr in a two step Grignard reaction. The crystal structure of 1 as determined by single crystal X-ray crystallography exhibits a nearly planar PhNMe2 moiety and an unusual gauche array of the phenyl and the acetylene group with respect to rotation around the Si-Si bond. Full geometry optimization (B3LYP/6-31+G**) of the gas phase structures of 1-5 affords minima for the gauche and the anti rotational isomers, both being very close in energy with a rotational barrier of only 3-5 kJ/mol. Experimental and calculated (time-dependent DFT B3LYP/TZVP) UV absorption data of 1-5 show pronounced electronic interactions of the HC=C- and the C6H4X pi-systems with the central Si-Si bond. (c) 2007 Elsevier B.V. All rights reserved.