Oxidative Addition of Biphenylene and Chlorobenzene to a Rh(CNC) Complex

Abstract

The synthesis and organometallic chemistry of rhodium(I) complex [Rh(CNC-Me)(SOMe₂)][BAr^F ₄], featuring NHC-based pincer and labile dimethyl sulfoxide ligands, is reported. This complex reacts with biphenylene and chlorobenzene to afford products resulting from selective C-C and C-Cl bond activation, [Rh(CNC-Me)(2,2'-biphenyl)(OSMe₂)][BAr^F ₄] and [Rh(CNC-Me)(Ph)Cl(OSMe₂)][BAr^F ₄], respectively. A detailed DFT-based computational analysis indicates that C-H bond oxidative addition of these substrates is kinetically competitive, but in all cases endergonic: contrasting the large thermodynamic driving force calculated for insertion of the metal into the C-C and C-Cl bonds, respectively. Under equivalent conditions the substrates are not activated by the phosphine-based pincer complex [Rh(PNP-<i>i</i>Pr)(SOMe₂)][BAr^F ₄].