Transforming PPh3 into bidentate phosphine ligands at Ru–Zn heterobimetallic complexes (MKW dedicates this paper to Professor Robin Perutz FRS on the occasion of his 70th birthday. Thank you Robin for the enthusiasm, guidance, encouragement and friendship over the last 30 years.)

The reaction of [Ru(PPh3)3Cl2] with excess ZnMe2 led to P–C/C–H bond activation and P–C/C–C bond formation to generate a chelating diphenylphosphinobenzene ligand as well as a cyclometallated (diphenylphosphino)biphenyl group in the final product of the reaction, [Ru(dppbz)(PPh2(biphenyl)′)(ZnMe)] (1; dppbz = 1,2-bis(diphenylphosphino)benzene); PPh2(biphenyl)′ = cyclometallated PPh2(biphenyl). The mechanism of reaction was studied and C–C coupling to give a bidentate 2,2′-bis(diphenylphosphino)biphenyl (BIPHEP) ligand was suggested to be one of the key steps of the process. This was confirmed by the reaction of [Ru(BIPHEP)(PPh3)HCl] with ZnMe2, which also gave 1. An analogous set of steps took place upon addition of ZnMe2 to [Ru(rac-BINAP)(PPh3)HCl] (rac-BINAP = racemic(2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) to give [Ru(dppbz)(PPh2(binaphthyl)′)ZnMe] (3). H2 and the C–H bond of PhC≡CH added across the Ru–Zn bond of 1, and also reversed the phosphine cyclometallation, to give [Ru(dppbz)(Ph2P(biphenyl))(H)2(H)(ZnMe)] (4) and [Ru(dppbz)(Ph2P(biphenyl))(C≡CPh)2(H)(ZnMe)] (5) respectively.