Synthesis and crystal structures of novel silylsubstituted diphosphanes

摘要

Reaction of two equivalents of lithium hypersilylphosphanide (hypersilyl, Hyp = tris(trimethylsilyl) silyl) with dichlorotetramethyldisilane at low temperatures gives [HypPH-SiMe2-](2) 1, a compound with high steric protection on both phosphane functionalities. Dehydrogenation reaction of 1 with n-butyl lithium yields the dilithiated [2.1.1] bicyclic phosphanide salt [HypPLi-SiMe2-](2) 2. The bicyclic structure is confirmed by NMR spectroscopy and X-ray diffraction analysis. As a major byproduct during the synthesis of 1 as well as via reaction of 2 with dichlorotetramethyldisilane, 1,4-diphospha-cyclosilahexane [HypP-(SiMe2)(2)-](2) 3 is obtained. X-Ray diffraction analysis shows exclusive formation of the trans-conformer 3a in the solid state, which is supported by calculations at the level of density functional theory (DFT). (C) 2014 Elsevier B.V. All rights reserved.