Citation:
Abstract:
The title compound, C24H47PSi2, is the first organophosphane bearing two tert-butyldimethylsilyl ( TBDMS) groups to be crystallographically characterized, even though TBDMS is a very popular bulky silyl group. The structure is a considerably flattened trigonal pyramid, with the sum of the C/Si-P-C/Si angles being 333.35 (6)degrees, which can be attributed to the steric pressure from the three bulky groups. The P-Si distances [2.2605 (6) and 2.2631 (6) angstrom] are normal, while the P-C distance [1.8646 (12) angstrom] is long (outside the s.u. values) compared with related structures. The plane of the aryl ring approximately bisects the Si-P-Si angle, quite unlike the secondary (tert-butyldimethylsilyl)(2,6-diisopropylphenyl)phosphane bearing only one TBDMS group, in which the single Si atom is perpendicular to the aryl ring. The title structure conforms closely to that predicted from B3LYP/6-31G(d) calculations, although the calculations overestimate the degree of planarity. The compound crystallizes centrosymmetrically in the space group P (1) over bar as isolated molecules.
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Times Cited: 0Boere, Rene T. Taghavikish, MonaPart 10