Nitrogen-bridged bidentate phosphaalkene ligands

Abstract

Nitrogen-bridged bidentate phosphaalkenes reveal several exceptional properties as a new class of P=C-unsaturated diphosphinoamine (PNP) ligands: N–Si bond cleavage of the first N-silylimino-bridged bis-phosphaalkene (R2C=P)2NSiMe3 (R = iPrMe2Si) with chlorides of AgI, AuI, and RhI leads to complexes of the 5c-6π-heteropentadienide imidobisphosphaalkene anion; double Cl– transfer from PtCl2 and PdCl2 to coordinated phosphaalkene phosphorus atoms of P-diphenylphosphanylamino phosphaalkenes R2C=PN(R')PPh2 (R' = Me3Si or iPrMe2Si; R = tBu, 1-Ada) furnishes unprecedented bis-chelate P-chloroylid complexes M[R2CP(Cl)N(R')PPh2]2 (M = Pd, Pt); CO- and RhI-induced coupling of two P-diphenylphosphanylamino phosphaalkenes under disilylketene elimination provides trigonal–bipyramidal RhIII complexes with novel tetradentate dianionic “PNP–C–PNP” ligands R2C[P(–)N(R')PPh2]2.