Reactions of an anionic chelate phosphane/borata-alkene ligand with [Rh(nbd)Cl]2, [Rh(CO)2Cl]2 and [Ir(cod)Cl]2

Abstract

Borata-alkenes can serve as anionic olefin equivalent ligands in transition metal chemistry. A chelate ligand of this type is described and used for metal coordination. Deprotonation of the Mes₂P(CH₂)₂B(C₆F₅)₂ frustrated Lewis pair in the α-CH[B] position gave the methylene-bridged phosphane/borata-alkene anion. It reacted with the [Rh(nbd)Cl] or [Rh(CO)₂Cl] dimers to give the respective neutral chelate [P/CB][Rh] complexes. The reaction of the [P/CB]⁻ anion with [Ir(cod)Cl]₂ proceeded similarly, only that the complex underwent a subsequent oxidative addition reaction at the mesityl substituent. Both the resulting Ir(III)hydride complex 15 and the P/borata-alkene Rh system 12 were used as hydrogenation catalysts. The [P/CB(C₆F₅)₂]Rh(nbd) complex 12 served as a catalyst for arylacetylene polymerization.