Synthesis and Theoretical Investigation of Diphosphastannylenes

The factors affecting the stabilization of diphosphastannylenes, such as substituent size, steric demand, and type of substituent (aryl, alkyl, silyl) were investigated via a comprehensive DFT and experimental investigation. The influence of various substituents (H, Me, tBu, Ph, TMS, Hyp = (Si(SiMe₃)₃)) on the pyramidalization of the phosphorus centers and cone angle determination of those substituents were carried out. Through these considerations, ligand systems capable of isolating a stable Sn(II) species were determined. Synthetic work led to the isolation of dimeric supermesityl(trimethylsily)phosphanides, 2,4,6-tris(t-butyl)phenyl trimethylsilyl lithium phosphanide, 2,4,6-tris(t-butyl)phenyl trimethylsilyl potassium phosphanide, and one hypersilylphosphanide [HypP(SiMe₃)K·DME]. In addition to that, a novel monomeric diphosphastannylene [HypP(SiMe₃)]2Sn was isolated as well as confirmed by experimental and calculated NMR data and single crystal X-ray analysis.