47895-57-8Relevant academic research and scientific papers
Reversible opening of the triangular structure of a sulfido-bridged ZrRh2 early-late heterobimetallic complex induced by Bis-(diphenylphosphino)methane
Hernandez-Gruel, Marc A. F.,Lahoz, Fernando J.,Dobrinovich, Isabel T.,Modrego, F. Javier,Oro, Luis A.,Perez-Torrente, Jesus J.
, p. 2616 - 2622 (2007)
Reaction of the early - late heterobimetallic complexes [Cp tt2Zr(μ3-S)2{M(CO)} 2(μ-dppm)] (M = Rh, Ir) with dppm (bis-(diphenylphosphino)methane) yields the compounds [Cptt2Zr(μ-S)2M(μ- CO)2(μ-dppm)M(η2-dppm)] (M = Rh (3), Ir (4)). The molecular structure of 3 shows a bent trimetallic ZrRhRh chain with tetrahedral, trigonal-bipyramidal, and square-pyramidal geometries, respectively. This trinuclear compound exhibits a mixed-valence Rh(II) - Rh(0) metal - metal bonded unit that results from the unusual chelating coordination of the metalloligand [Cptt2Zr(S)2]2- and is further stabilized by the presence of two unsymmetrical bridging carbonyl ligands, which interact with the unsaturated Rh(II) metal. The formation of 3 is reversible, and the equilibrium 1 + dppm ? 3 has been observed in solution (K ≈ 16 at 22 °C in C6D6). The opening of the triangular core in the heterotrimetallic compound [Cptt2Zr(μ 3-S)2-{Rh(CO)}{Ir(CO)}(μ-dppm)] (5) is not selective and gives the compounds [Cptt2Zr(μ-S) 2Rh(μ-CO)2(μ-dppm)Ir(η2-dppm)] (6) and [Cptt2Zr(μ-S)2Ir(μ-CO) 2(μ-dppm)Rh(η2-dppm)] (7) in a 3:1 molar ratio.
HRh(dppb)2, a powerful hydride donor
Price, Andrew J.,Ciancanelli, Rebecca,Noll, Bruce C.,Curtis, Calvin J.,DuBois, Daniel L.,Rakowski DuBois
, p. 4833 - 4839 (2002)
The Rh(I) and Rh(III) hydrides HRh(dppb)2 and [HRh(dppb)2(NCCH3)](BF4)2 (where dppb is 1,2-(bis(diphenylphosphino)benzene) have been prepared, and a structural study of [HRh-(dppb)2(NCCH3)](BF4)2 has been completed. The latter complex is an octahedral complex with a trans arrangement of the hydride and acetonitrile ligands. A pKa value of 9.4 was measured for this complex by equilibration of [Rh(dppb)2](BF4) with 4-bromoanilinium tetrafluoroborate in acetonitrile. [Rh(dppb)2](BF4) reacts with H2 in the presence of Pt(dmpp)2, which acts as a base, to form HRh(dppb)2 and [HPt(dmpp)2](BF4) (where dmpp = 1,2-bis-(dimethylphosphino)propane). An equilibrium constant of 0.42 ± 0.2 was measured for this reaction. Using this equilibrium measurement and a thermodynamic cycle, the hydride donor ability (δG°H-H-) of HRh(dppb)2 was determined to be 34 kcal/mol. This value indicates that HRh(diphosphine)2 complexes are powerful hydride donors. Similarly the pKa value of HRh-(dppb)2 was calculated to be 35 from a thermodynamic cycle that included the potential of the Rh(I/-I) couple (E1/2 = -2.02 V vs ferrocene). These results combined with results from the literature suggest the following order of hydricity for five-coordinate, 18-electron hydrides: second row > third row > first row. Similarly an acidity order of second row ≥ first row > third row is deduced.
Heterobinuclear IrRh, RuRh and RuIr Complexes with Pyrazolate Bridging Ligands: Reactivity towards Chelating Diphosphines; Crystal Structure of BPh4*0.5MeOH
Carmona, Daniel,Ferrer, Joaquina,Lahoz, Fernando J.,Oro, Luis A.,Reyes, Josefa,Esteban, Montserrat
, p. 2811 - 2820 (2007/10/02)
Complexes of general formula 1-5 and i-p)Ru(μ-pz)(μ-Cl)2Rh(cod)> 7 were prepared starting from mononuclear acetylacetonate and pyrazole or pyrazolate-containing moieties.Complexes 1-5 react with CO yielding derivatives 8-12.Complexes 13 and i-p)ClRu(μ-pz)2Ir(CO)2> 12 react with NaX to give (X = I; 14; or N3, 15) and i-p)Ru(μ-pz)2IrX(CO)2> (X = Br, 16; or I, 17.The dicarbonyl compound 10 and i-p)ClRu(μ-pz)2M'(CO)2> (M' = Rh, 11; or Ir, 12) react with diphosphines (L-L) or 1,2-bis(diphenylarsino)ethane (dpae) and NaBPh4 or AgBF4 affording cationic complexes >A 23-31 A = BPh4 or BF4 (not all possible combinations)>.In this reaction intermediates >A have been isolated in some cases.The crystal structure of one of these BPh4*0.5MeOH 19 has been determined by X-ray diffraction methods.Crystals are monoclinic, space group P21/c, a = 15.996(2), b = 22.199(4), c = 18.874(3) Angstroem, β = 115.04(1) deg and Z = 4.The complex cation consists of two iridium atoms bridged by two pyrazolates and one ketonic carbonyl group.An η5-C5Me5 ligand, a chelate dppen and a terminal CO group complete the co-ordination spheres of the iridium atoms, which are separated by 3.440(5) Angstroem.
