Electrophilic C–H activation of benzene with a Shilov-inspired rhodium(III) diimine complex

•The complex [Rh(diimine) (CH3) (H2O)3]2+ has been synthesized and characterized.•The complexes are octahedral and water soluble.•X-ray structures have been obtained for all complexes.•[Rh(diimine) (CH3) (H2O)3]2+ can catalyze H/D exchange between benzene and CF3CO2D.

Four new air and water stable, organometallic rhodium(III) complexes trans-RhIII(α-diimine) (CO)I2Me, 1, [RhIII(α-diimine) (C(O)Me) (H2O)3][BF4]2, 2, [RhIII(α-diimine)Me(H2O)3] [BF4]2, 3, and RhIII(α-diimine) (C(O)Me) (H2O) (OC(O)CF3)2, 4 (α-diimine = 1,4-bis(Ar)-2,3-dimethyl-1,4-diaza-1,3-butadiene, Ar = 3,5-dimethylphenyl) were synthesized and characterized by X-ray crystallography. H/D exchange of C6H6 with TFA-d1 (TFA = trifluoroacetic acid) was observed with 4 mol% loading of 3 at 100 °C with 137 turnovers (98% completion at 91% deuterium incorporation) in 24 h. 3 showed sustained catalytic activity towards H/D exchange of benzene even after three iterations of catalyst recycling.

Graphical abstractThis article describes the synthesis and characterization of the complex [Rh(diimine) (CH3) (H2O)3]2+. The complex is octahedral and water soluble, and can catalyze H/D exchange between benzene and CF3CO2D.Figure optionsDownload full-size imageDownload as PowerPoint slide