UC Santa Barbara

Herein we report the synthesis and characterization of a linear, two-coordinate Pt(II) ketimide complex, Pt(N═C^tBu₂)₂ (1), formed via the reaction of PtCl₂(1,5-COD) with 2 equiv of Li(N═C^tBu₂). Also generated in the reaction is the bimetallic complex [(^tBu₂C═N)Pt(μ-N,C-N═C(^tBu)C(Me)₂CH₂)Pt(N═C^tBu₂)] (2). Both complexes 1 and 2 have been characterized by NMR spectroscopy and X-ray crystallography. Notably, complex 1 exhibits short Pt-N distances (av. Pt-N = 1.817 Å) and an unusually deshielded ¹⁹⁵Pt chemical shift (δ_Pt = -629 ppm) with a large ¹J(¹⁹⁵Pt,¹⁴N) 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 σ-donation, π-donation, and π-backdonation.