X-RAY CRYSTAL-STRUCTURE OF CIS-H(PH3SI)PT[PH2P(CH2)(4)PPH2]CENTER-DOT-0.5 C6H6

The title compound, ylsilyl)-1,4-butanediyl-bis-(diphenylphosphine)pla num(II) (I), crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 9.472(4), b = 16.924(5), c = 25.799(4) Angstrom, beta = 9 1.29(3)degrees and Z = 4. The structure was served using the direct me thods and refined by the full-matrix least-squares procedure to yield residuals of R = 0.024 and R-w = 0.025 based on 4160 unique reflection s. The square-planar geometry about the Pt atom is angularly distorted with P(1)-Pt-P(2) and Si-Pt-P(2) angles of 103.5(1) and 102.1(1)degre es, respectively. The Pt-P(1) bond is longer than the Pt-P(2) bond due to the trans influence of the SiPh3 group. Distortion due to steric b ulk of the ligands is accommodated by the opening of the tetrahedral a ngles at the silicon and phosphorous atoms.