Dynamic nuclear magnetic resonance studies of the η3-triphenylcyclopropenyl complexes [M(η3-C3Ph3)L]PF6[M = Ni, Pd or Pt; L = MeC(CH2PPh2)3]. Crystal structure of the platinum derivative
Abstract
The dynamic behaviour of the three complexes [M(η3-C3Ph3)L]PF6[M = Ni 1, Pd 2 or Pt 3; L = 1,1,1-tris(diphenylphosphinomethyl)ethane] has been investigated through 13C-{1H} variable-temperature NMR spectroscopy. The spectra indicate a temperature-dependent fluxionality 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 parameters and fluxional behaviour. Crystal data for 3: monoclinic, space group P21/n, a= 17.129(3), b= 17.517(3), c= 17.968(7)Å, β= 95.11 (3)°, Z= 4, R= 0.037.