Organopalladium(IV) and platinum(IV) complexes containing the bis(pyrazol-1-yl)borate ligand. Structures of PtMe{(pz)2BH2}(py) (py=pyridine) and Pt(mq)Me2{(pz)2BH2} (mq=8-methylquinolinyl) and detection of a neutral organopalladium(IV) phosphine complex

Abstract

Neutral palladium(IV) complexes containing the bis(pyrazol-1-yl)borate ligand, PdMe3{(pz)2BH2}(L) [L=py-d5 (4), PMe2Ph (6)], are generated in solution by oxidative addition of iodomethane to [PdMe2{(pz)2BH2}]− at −70 °C followed by addition of L; the Pd(IV) complexes reductively eliminate ethane above 0 °C. Stable Pt(IV) analogues of 4 and 6 have been isolated, and comparison of NMR spectra for Pd(IV) and Pt(IV) species support structural assignments for the unstable Pd(IV) complexes. The complex PtMe3{(pz)2BH2}(py) (1a) has been characterised by X-ray diffraction, together with Pt(mq)Me2{(pz)2BH2} (2) (mq=8-methylquinolinyl); both complexes show a fac-PtC3 configuration for Pt(IV), and for 2 the PtN distances are ~0.03 A shorter than in the isostructural Pd(IV) complex.