Reactivity of rhodium and iridium peroxido complexes towards hydrogen in the presence of B(C6F5)3 or [H(OEt2)2][B{3,5-(CF3)2C6H3}4]Electronic supplementary information (ESI) available: Experimental section and analytical data. See DOI: 10.1039/c8dt03853h

The peroxido complexes trans -[M(4-C 5 F 4 N)(O 2 )(CN t Bu)(PR 3 ) 2 ] ( 1 : M = Rh, R = Et; 2a : M = Ir, R = iPr) can be used in the metal-mediated hydrogenation of O 2 . The reaction of trans -[Rh(4-C 5 F 4 N)(O 2 )(CN t Bu)(PEt 3 ) 2 ] ( 1 ) with B(C 6 F 5 ) 3 and H 2 gave trans -[Rh(4-C 5 F 4 N)(CN t Bu)(PEt 3 ) 2 ] ( 3 ), OPEt 3 and (H 2 O)·B(C 6 F 5 ) 3 , whereas treatment of [H(OEt 2 ) 2 ][B{3,5-(CF 3 ) 2 C 6 H 3 } 4 ] with 1 in the presence of H 2 yielded trans -[Rh(4-C 5 F 4 N)(CN t Bu)(PEt 3 ) 2 ] ( 3 ) and H 2 O 2 . The reactivity of 2a towards B(C 6 F 5 ) 3 and BClCy 2 was also studied and an intermediate was detected which is assigned to be trans -[Ir(4-C 5 F 4 N)(Cl)(OOBCy 2 )(CN t Bu)(PiPr 3 ) 2 ] ( 4a ). Rh and Ir peroxido complexes have been studied in the metal-mediated hydrogenation of O 2 . Dissimilar reaction pathways have been found on using the Lewis-acid B(C 6 F 5 ) 3 or the Brønsted-acid [H(OEt 2 ) 2 ][B{3,5-(CF 3 ) 2 C 6 H 3 } 4 ] to give H 2 O·B(C 6 F 5 ) 3 or H 2 O 2 .