PBiP Pincer Complexes of Platinum, Palladium, and Iridium Featuring Metal–Metal Bonds Synthesized by Oxidative Addition of Bismuth–Halide Bonds

Abstract

The compound BiCl(o-PPh2-C6H4)2, PBiP-Cl, which in previous work had been shown to form complexes with pronounced M→Bi character, when metal(I) ions of group 11 or PtII and PdII ions were coordinated, behave differently in contact with late metal atoms in low oxidation states, known to easily undergo oxidative additions: Treatment of PBiP-Cl with M(PPh3)4, with M = Pt, Pd, led to the formal insertion of M into the Bi–Cl bond to yield complexes [MCl(PBiP)]. Analogues PBiP-X with X = Br, I that could be accessed behaved similarly, producing [MX(PBiP)]. Both types of complexation reactions—coordination of PBiP-Cl as an ambiphilic ligand and oxidative addition—were observed to occur when [Ir(acac)(cod)] was chosen as the precursor compound. NMR investigations clearly indicated the presence of [IrI(acac)(PBiP-Cl)] and [IrIII(acac)Cl(PBiP)] beside each other in solution, from which, however, only [IrIII(acac)Cl(PBiP)] could be crystallized. DFT results showed that both products differ only slightly in energy. R...