DYNAMIC NUCLEAR-MAGNETIC-RESONANCE STUDIES OF THE ETA(3)-TRIPHENYLCYCLOPROPENYL COMPLEXES [M(ETA(3)-C(3)PH(3))L]PF6 [M=NI, PD OR PT - L=MEC(CH(2)PPH(2))(3)] - CRYSTAL-STRUCTURE OF THE PLATINUM DERIVATIVE

The dynamic behaviour of the three complexes [M(eta(3)-C(3)Ph(3))L]PF6 [M = Ni 1, Pd 2 or Pt 3; L = 1,1,1 -tris(diphenylphosphinomethyl)etha ne] has been investigated through C-13-{H-1} variable-temperature NMR spectroscopy. The spectra indicate a temperature-dependent fluxionalit y of the cyclopropenyl ring, with the rotational barrier increasing in the order Ni < Pd < Pt. The molecular structure of 3, established by single-crystal X-ray diffraction studies, shows that the co-ordination geometry of the platinum complex is fully comparable with that of the nickel analogue, indicating no correlation between structural paramet ers and fluxional behaviour. Crystal data for 3: monoclinic, space gro up P2(1)/n, a = 17.129(3), b = 17.517(3), c = 17.968(7) Angstrom, beta = 95.11 (3)degrees, Z = 4, R = 0.037.