Synthesis and Characterization of a Linear, Two-Coordinate Pt(II) Ketimide Complex

Herein we report the synthesis and characterization of a linear, two -coordinate Pt(II) ketimide complex, Pt(N=(CBu2)-Bu-t)(2) (1), formed via the reaction of PtCl2(1,5-COD) with 2 equiv of Li(N=(CBu2)-Bu-t). Also generated in the reaction is the bimetallic complex [((Bu2C)-Bu-t=N)Pt(mu-N,C-N=C(Bu-t)C-(Me)(2)CH2)Pt(N=(CBu2)-Bu-t)] (2). Both complexes 1 and 2 have been characterized by NMR spectroscopy and X-ray crystallography. Notably, complex 1 exhibits short Pt-N distances (ay. Pt-N = 1.817 angstrom) and an unusually deshielded Pt-195 chemical shift (delta(Pt) = -629 ppm) with a large (1)J(Pt-195,N-14) coupling constant (537 Hz). These data, in combination with a detailed density functional theory electronic structure analysis, reveal the presence of highly covalent Pt=N multiple bonds formed by a combination of sigma-donation, pi-donation, and pi-backdonation.