Unsymmetric Ir and RhIr Dinuclear Complexes Supported by a Linear Tetraphosphine -dpmppp, Showing High Reactivity for O, H, and HCl.

Unsymmetric dinuclear Ir(I) complexes, [IrCl(L)(-dpmppp)] (L = XylNC (), BuNC (), CO ()), were synthesized using -PhPCHP(Ph)(CH)P(Ph)CHPPh (-dpmppp), which supports - (M) and (M) metal sites, and exhibited high reactivity for O, H, and HCl. The IrRh heterodinuclear complexes, [MMCl(L)(-dpmppp)] () (MM = IrRh, RhIr; L = XylNC, CO ( = , )), were also synthesized and used together with the Rh complexes () to elucidate the role of each metal site. For the reactions of O, and showed higher reactivity than those of and , giving η-peroxide complexes [{MCl}{M(η-O)(XylNC)}(-dpmppp)] (, ), from which O would not dissociate. All the CO complexes (M, M = Ir or Rh) showed no reactivity for O. In the reactions with H, reacted with H to give the dihydride complex, [{IrCl}{Ir(H)L}(-dpmppp)] () and the tetrahydride complex, [{Ir(H)Cl}(μ-H){Ir(H)L}(-dpmppp)] (), while gave the dihydride complex, and and gave no hydride complexes. Reactions of with HCl afforded the dihydride complexes, [{IrCl}(μ-H){Ir(H)Cl(XylNC)}(-dpmppp)] (), [{Ir(H)Cl}(μ-H){MCl(L)}(-dpmppp)] (M = Ir, L = CO (); M = Rh, L = XylNC (), CO ()), and [{Rh(H)Cl}(μ-Cl){Ir(H)Cl(XylNC)}(-dpmppp)] (), the structures varying depending on M and M as well as L.