Synthesis and reactivity of PC(sp3)P-pincer iridium complexes bearing a diborylmethyl anion.

Novel PCP-pincer iridium complexes bearing a diborylmethyl anion were synthesized. Strong σ-electron-donation to the metal and significant π-backdonation from the metal to boron atoms at the β-position were observed both experimentally and computationally. H/D exchange of the aromatic C-H bond proceeded smoothly and, in addition, the α-methine-hydrogen between boron atoms was found to be replaced with deuterium in benzene-d6 solution possibly through diborylcarbene metal complexes as intermediates.