Organopalladium(IV) and platinum(IV) complexes containing the bis(pyrazol-1-yl)borate ligand. Structures of PtMe 3{(pz) 2BH 2}(py) (py=pyridine) and Pt(mq)Me 2{(pz) 2BH 2} (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, PdMe 3{(pz) 2BH 2}(L) [L=py-d 5 ( 4), PMe 2Ph ( 6)], are generated in solution by oxidative addition of iodomethane to [PdMe 2{(pz) 2BH 2}] − 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 PtMe 3{(pz) 2BH 2}(py) ( 1a) has been characterised by X-ray diffraction, together with Pt(mq)Me 2{(pz) 2BH 2} ( 2) (mq=8-methylquinolinyl); both complexes show a fac-PtC 3 configuration for Pt(IV), and for 2 the PtN distances are ∼0.03 Å shorter than in the isostructural Pd(IV) complex.