SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF HETERODINUCLEAR RUM (M=CU(I), AG(I), AU(I), RH(I), AND IR(I)) AND HETEROTRINUCLEAR RUAG2 AND RURHAG COMPOUNDS DERIVED FROM THE METAL-COMPLEX LIGAND BIS(PYRAZOLATO) (P-CYMENE)(PYRAZOLE)RUTHENIUM(II)

The reaction of the mononuclear ruthenium p-cymene pyrazolate complex [(eta(6)-p-cymene)-Ru(pz)(2)(Hpz)] (1) (p-cymene p-isopropylmethylbenzene; Hpz = pyrazole, C3H4N2) with the halide triphenylphosphine complexes [MCl(PPh(3))](x) and KOH led to the corresponding heterodinuclear compounds [(eta(6)-p-cymene)Ru(pz)(3)M(PPh(3))] (M = Cu (2), Ag (3), Au (4)). In solution, complexes 2-4 showed a dynamic behavior consisting of exchange between terminal and bridging pyrazolate groups accompanied by dissociation of the phosphine ligand. Complex 3 reacted with AgBF4 and PPh(3) to yield the heterotrinuclear RuAg2 complex [(eta(6)-p-cymene)Ru(mu-pz)(3){Ag(PPh(3))}(2)]BF4 (5) which was also fluxional. Heterodinuclear derivatives of formula [eta(6)-p-cymene)(pz)Ru(mu-pz)(2)ML(2)] (M = Rh; L(2) = 1,5-cyclooctadiene (COD) (6), (CO)(2) (7). M = Ir; L(2) = (CO)(2) (8)) have been prepared by treating complex 1 with the appropriate [M(acac)L(2)] (acac = acetylacetonate) compounds. The carbonyl complexes 7 and 8 reacted with mono- or diphosphines, rendering [(eta(6)-p-cymene)(pz)Ru(mu-pz)(2)ML(2)] (M = Rh; L(2) = CO, PPh(3) (9), CO, P(OMe)(3) (10), CO, bis(diphenylphosphinojmethane (dppm) (11), dppm (14), 1,2-bis(diphenylphosphino)ethane (dppe) (15), cis-1,2-bis(diphenylphosphino)ethylene (dppen) (16), (R)-(+)-1,2-bis(diphenylphosphino)propan (R-prophos)(l7a,b). M Ir; L(2) = CO, PPh(3) (12), CO, dppm (13), dppe (18)). Protonation of 6-9 and 12 with HBF4 afforded the corresponding cationic complexes [(eta(6)-p-cymene)(Hpz)RU(mu C-Pz)(2)ML(2)]BF4 (M = Rh; L(2) = COD (19), (CO)(2) (20), CO, PPh(3) (21). M = Ir; L(2) (CO)(2) (22), CO, PPh(3)(23)). The molecular structure of complex 22 has been determined by X-ray diffraction methods. Crystals are monoclinic, space group P2(I)/c, with cell parameters a = 7.9909(6) Angstrom, b = 17.0590(9) Angstrom, c = 19.083(2) Angstrom, beta = 93.94(1)degrees, and Z = 4. The molecule exhibits two bridging pyrazolate groups between the metals. No direct intermetallic interaction is observed, the Ru ... Ir distance being 3.6770(6) Angstrom. In the solid state, a clear hydrogen bond is present between one fluorine atom ofthe tetrafluoroborate anion and the pyrazole ligand. The heterotrinuclear RuRhAg cationic derivatives [(eta(6)-p-cymene)Ru[(mu-pz)Ag(PPh(3))][(mu-pz)(2)RhL(2)]]BF4 (L(2) = COD (24), CO, PPh(3) (25)) have been prepared on the addition of equimolar amounts of AgBF4 and PPh(3) to complexes 6 and 9, respectively.