Oxy- and Thio Phosphorus Acid Derivatives of Tin. VII. The Crystal and Molecular Structure of Alpha-Phenylphosphonatotrimethyltin(IV) at 138 K. A Unique, One-dimensional, Helical

摘要

Alpha-Phenylphosphonatotrimethyltin(IV), C9H1503PSn, forms colorless crystals. The structure was solved by the heavy atom method to an R value of 0.046 for the 2578 reflections collected at 138 + or - 2K on an Enraf-Nonius CAD/4 automatic diffractometer using MoK sub alpha radiation. The molecular units associate to form an infinite, one-dimensional polymer in which planar trimethyltin(IV) groups are axially-bridged by -O-P-O- linkages of the phenylphosphonate ligand to yield an almost perfect trigonal bipyramid at tin. The chains are linear at the tin atoms, but bent through a bite angle of 115.4(3) deg at phosphorus. The chains propogate helically through the crystal, and each phenylphosphonate P=O and P-OH group is hydrogen bonded, holding adjacent helicies, turning in opposite directions, into two-dimensional sheets. The phenyl groups point outward from the center of the propagating helicies, separating the sheets from one another. Tin atoms occupy two non-equivalent environments, alternating metal atoms forming either two short or two long bonds to oxygen.