An Unprecedented Family of Luminescent Iridium(III) Complexes Bearing a Six-Membered Chelated Tridentate C^N^C Ligand

A new family consisting of three luminescent neutral Ir­(III) complexes with the unprecedented [Ir­(C^N^C)­(N^N)­Cl] architecture, where C^N^C is a bis­(six-membered) chelating tridentate tripod ligand derived from 2-benzhydrylpyridine (bnpy) and N^N is 4,4′-di-tert-butyl-2,2′-bipyridine (dtBubpy), is reported. X-ray crystallography reveals an unexpected and unusual double C–H bond activation of the two distal nonconjugated phenyl rings of the bnpy coupled with a very short Ir–Cl bond trans to the pyridine of the bnpy ligand. Depending on the substitution on the bnpy ligand, phosphorescence, ranging from yellow to red, is observed in dichloromethane solution. A combined study using density functional theory (DFT) and time-dependent DFT (TD-DFT) corroborates the mixed charge-transfer nature of the related excited states.