Thermal and photochemical oxidative addition of alkyl halides to the cyclometalated complex cis-bis[2-(2-thienyl)pyridine]platinum(II)

Abstract

The homoleptic, cyclometalated complex cis-bis[2-(2'-thienyl)pyridine] platinum(II) (1, Pt(2'-thpy) 2 ) undergoes thermal or photochemical oxidative addition (TOA or POA) reactions with a wide range of alkyl halides. These reactions are found to be highly stereoselective, yielding in most cases Pt(IV) complexes with the halide and the σ-bonded C(alkyl) atom in the cis position, in a C,C,C-fac arrangement. In some cases, trans addition of R-X was observed, followed by trans→cis isomerization, either at room temperature or on heating. Extensive use was made of 1 H NMR spectroscopy in assigning the configurations, and the 2-D COSY spectra, measured for a few of the Pt(IV) complexes, were helpful in making the chemical shift assignment