C-H, N-H, and O-H Bond Activations to Prepare Phosphorescent Hydride-Iridium(III)-Phosphine Emitters with Photocatalytic Achievement in C-C Coupling Reactions.

Complex IrH 5 (P i Pr 3 ) 2 ( 1 ) activates two different σ-bonds of 3-phenoxy-1-phenylisoquinoline, 2-(1 H -benzimidazol-2-yl)-6-phenylpyridine, 2-(1 H -indol-2-yl)-6-phenylpyridine, 2-(2-hydroxyphenyl)-6-phenylpyridine, N -(2-hydroxyphenyl)- N '-phenylimidazolylidene, and 1,3-di(2-pyridyl)-4,6-dimethylbenzene to give IrH{κ 3 - C,N,C -[C 6 H 4 -isoqui-O-C 6 H 4 ]}(P i Pr 3 ) 2 ( 2 ), IrH{κ 3 - N,N,C -[NBzim-py-C 6 H 4 ]}(P i Pr 3 ) 2 ( 3 ), IrH{κ 3 - N,N,C -[Ind-py-C 6 H 4 ]}(P i Pr 3 ) 2 ( 4 ), IrH{κ 3 - C,N,O -[C 6 H 4 -py-C 6 H 4 O]}(P i Pr 3 ) 2 ( 5 ), IrH{κ 3 - C,C,O -[C 6 H 4 -Im-C 6 H 4 O]}(P i Pr 3 ) 2 ( 6 ), and IrH{κ 3 - N,C,C -[py-C 6 HMe 2 -C 5 H 3 N]}(P i Pr 3 ) 2 ( 7 ), respectively. The activations are sequential, with the second generally being the slowest. Accordingly, dihydride intermediates IrH 2 {κ 2 - C,N -[C 6 H 4 -isoqui-O-C 6 H 5 ]}(P i Pr 3 ) 2 ( 2d ), IrH 2 {κ 2 - N,N -[NBzim-py-C 6 H 5 ]}(P i Pr 3 ) 2 ( 3d ), IrH 2 {κ 2 - N,N -[Ind-py-C 6 H 5 ]}(P i Pr 3 ) 2 ( 4d ), and IrH 2 {κ 2 - N,C -[py-C 6 HMe 2 -py]}(P i Pr 3 ) 2 ( 7d ) were characterized spectroscopically. Complexes 3 and 5 are green phosphorescent emitters upon photoexcitation, exhibiting good absorption over a wide range of wavelengths, emission quantum yields about 0.70 in solution, long enough lifetimes (10-17 μs), and reversible electrochemical behavior. In agreement with these features, complex 3 promotes the photocatalytic α-amino C(sp 3 )-H arylation of N , N -dimethylaniline and N -phenylpiperidine with 1,4-dicyanobenzene and 4-cyanopyridine under blue LED light irradiation. The C-C coupling products are isolated in high yields with only 2 mol % of photocatalyst after 24 h.