X-ray and neutron diffraction studies of the crystal and molecular structures of tris(ethylene)platinum and bis(ethylene)(tetrafluoroethylene)platinum

Abstract

The structures of tris(ethylene)platinum and bis(ethylene (tetrafluoroethylene)platinum have been established by X-ray and neutron diffraction experiments. Tris(ethylene)platinum [Pt(C 2 H 4 ) 3 ] (I), formed by the displacement of 1, 5-cyclooctadiene from bis(1, 5-cyclooctadiene)platinum by ethylene, crystallizes in the trigonal space group R3̅m ( a = b = 7.225(4), c = 11.054(7) Ǻ, 120K) and [Pt(C 2 H 4 ) 2 (C 2 F 4 )] (II), obtained by the replace­ment of one ethylene ligand in (I) by tetrafluoroethylene, is shown to be triclinic, space group A1̄ with a = 8.680(3), b = 7.432(3), c = 12.716(6), Ǻ α = 90.13(4), β = 109.42(3), γ = 90.17(3)° (155 K). In both complexes, the six ligated carbon atoms are coplanar with the Pt atom at distances dependent primarily on the nature of the substituent at the contact carbon atom: mean Pt–C(H) 2.218(2), mean Pt–C(F) 2.031(5). Concomi­tant variations are recorded for the C═C separations, namely C═C(H), 1.382(7); C═C(F), 1.435(6). (I) exhibits a positional disorder of the ethylene ligands between two equivalent sites.