Crystal structure of triethylplatinum(IV) chloride, tetra-µ₃-chlorotetrakis[triethylplatinum(IV)]

A three-dimensional X-ray crystal structure analysis on the compound [Et₃PtCl]₄ has been carried out with photographic observations made at room temperature. In a monoclinic unit cell having a= 16·65 b= 12·08, c= 17·00 Å, β= 90·5°, and space group P2₁/n, there are four tetrameric molecules which do not require any symmetry. The platinum, chlorine, and carbon atoms have been located and the molecule found to have approximate 23 (T) symmetry, compared with 43m(Td) for [Me₃PtCl]₄. With anisotropic vibration parameters for platinum and chlorine, and individual isotropic parameters for carbon atoms, refinement by least-squares gave R 0·082 for 1300 reflections.

Mean bond lengths (Å) are: Pt–Cl, 2·58 ± 0·05, Pt–C 2·07 ± 0·11, C–C 1·6 ± 0·2, and Pt 3·90 ± 0·015. Mean angles in the tetramer are Pt–Cl–Pt 98° and Cl–Pt–Cl 81°. The methyl groups are rigidly held by steric repulsions within one molecule.