Nitrogen versus metal protonation in pyrazolyborate complexes of rhodium(I) and iridium(I). Unexpected reactions of a cationic iridium(III) hydride

Protonation of [M(HBPz*3)(Co)2](Pz*= 3,5-dimethylpyrazol-1-yl) occurs at the nitrogen for M = Rh forming [Rh{η2-HBPz*2(Pz*H)}(CO)2][BF4], of which the X-ray crystal structure has been determined; for M = Ir a cationic IrIII hydride is formed which is attacked by strong nucleophiles at a carbonyl carbon.