Vibrational spectra and nuclear magnetic resonance parameters of some platinum(IV) complexes [PtX4L2] and [PtX5L]–(X = Cl, Br, or I; L = NMe3, PMe3, AsMe3, or SMe2)

Abstract

trans-[ PtX4L2](L = PMe3, AsMe3, or SMe2; X = Cl or Br) and, except X = Br for SMe2, cis-complexes have been isolated, together with the salts Prn4N[PtX5L], Prn4N[PtI5PMe3], Prn4N[PtCl5NMe3], and [PtCl3(PMe3)3] BF4. The vibrational spectra of the complexes have been studied. 1H N.m.r. measurements have been made for these and other halide derivatives which were prepared in situ but were unstable to isolation in a pure form. Values of JPtP and δp have been measured by heteronuclear INDOR and, in addition, those of related platinum(II) and palladium(II) compounds are reported. Approximate values of JPtN have been obtained from 1H(195Pt) INDOR in three cases. The spectroscopic parameters are discussed and it is concluded that variations in them are consistent with significant π-contribution to Pt–P bonding, at least in platinum(II) complexes.