CRYSTALLOGRAPHIC AND NMR-STUDIES OF PLATINUM(II) AND PALLADIUM(II) ETA-3-METHALLYL TRICHLOROSTANNATE OLEFINCOMPLEXES

Complexes of the type M(SnCl3)(eta-3-CH2C(CH3)CH2l(olef(M = Pt, Pd; olefin = styrene, ethylene, norbornene) have been prepared and their lH, 13C, and, in some cases, 119Sn and 195Pt NMR spectra recorded. Two-dimensional 'H NOE and 13C-lH correlation methods were used for assignment purposes. The structures for the platinum- (la) and palladium- (2a) styrene complexes have been determined by X-ray diffraction. The two compounds are isomorphous and crystallize in the triclinic space group P1 with cell constants a = 8.740 (2) A, b = 9.338 (2) A, c = 10.931 (2) A, alpha = 72.43 (l)°beta = 89.38 (1)°, and gamma = 73.33 (2)° for the Pd complex and a = 8.698 (2) A, b = 9.373 (2)A , c = 11.015 (2)8 ,alpha = 72.32, beta = 89.76O, and gamma = 73.30' for the Pt derivative. Both compounds have the olefin C-C vector almost parallel to the coordination plane (20.8 and 23.3O for la and 2a, respectively). Analyses of the NMR and crystallographic data lead to the conclusion that the SnC13 and olefin ligands both exercise a moderate trans influence with the former larger than the latter. Back-bonding from the metal to the olefin is suggested to be larger for Pt than Pd.