Synthesis and Electrochemistry of Heterobimetallic Ruthenium/Platinum and Molybdenum/Platinum Complexes

Abstract

As starting materials for heterobimetallic complexes, [RuCp(PPh(3))CO(PPh(2)H)]PF(6) and [RuCp(PPh(3))CO(eta(1)-dppm)]PF(6) were prepared from RuCp(PPh(3))(CO)Cl. In the course of preparing [RuCp(eta(2)-dppm)(eta(1)-dppm)]Cl from RuCp(Ph(3)P)(eta(1)-dppm)Cl, the new monomer RuCpCl(eta(1)-dppm)(2) was isolated. The uncommon coordination mode of the two monodentate bis(phosphines) was confirmed by X-ray crystallography [a = 11.490(1) Å, b = 14.869(2) Å, c = 15.447(2) Å, alpha = 84.63(1) degrees, beta = 70.55(1) degrees, gamma = 72.92(1) degrees, V = 2378.7(5) Å(3), d(calc) = 1.355 g cm(-)(3) (298 K), triclinic, P&onemacr;, Z = 2]. The dppm-bridged bimetallic complexes RuCp(PPh(3))Cl(&mgr;-dppm)PtCl(2), RuCpCl(&mgr;-dppm)(2)PtCl(2), and [RuCp(PPh(3))CO(&mgr;-dppm)PtCl(2)]PF(6) each exhibit electrochemistry consistent with varying degrees of metal-metal interaction. The cationic heterobimetallic complexes [Mo(CO)(3)(&mgr;-dppm)(2)Pt(H)]PF(6) and [MoCp(CO)(2)(&mgr;-PPh(2))(&mgr;-H)Pt(PPh(3))(MeCN)]PF(6) were prepared by chloride abstraction from the corresponding neutral bimetallic species and show electrochemical behavior similar to the analogous Ru/Pt complexes.

Synthesis, characterisation and theoretical studies on some piano-stool ruthenium and rhodium complexes containing substituted phenyl imidazole ligands

“…1). Peaks around 290 nm and 230 nm ascribed as intra-ligand transition [45,46]. On the basis of its position and intensity the low energy bands in the region 400-450 nm has been assigned to MLCT transitions [Ru(II)/Rh(III) ?…”

Catalysis of the Electrooxidation of Biomass-Derived Alcohol Fuels

“…Cyclic voltammetry of complexes 1-3 in the presence of methanol led to significant enhancement of oxidative current, consistent with a catalytic process. 35,43,44 Bulk electrolysis of methanol in the presence of the heterobimetallic complexes resulted in much higher current efficiencies than those obtained from the mononuclear models complexes CpRu(PPh 3 ) 2 Cl (5), and CpRu(r) 2 -dppm)Cl (6) suggesting that the second metal center enhances the catalytic activity. 9 Ru' = CpRu(PPh 3 ) 2 Cl.…”

“…There has been previous work which has examined several Mo/Pt and Ru/Pt heterobimetallic complexes in electrochemical processes. 35 The shifts in the oxidation potentials reflect the ability of the metal centers to communicate with each other through the bridging ligands. For example, the cationic [Mo(CO) 3^-dppm) 2 Pt(H)]PF 6 complex shows a 400 mV positive shift for both Mo(II/III) and Pt(MV) waves compared to the neutral Mo(CO) 3^-dppm) 2 Pt(H)Cl complex.…”

“…The first generation of heterobimetallic complexes Cp(PPh 3 )Ru^-Cl)^-dppm)PtCl 2 (l), 35 Cp(PPh 3 )Ru^-Cl)fa-dppm)PdCl 2 (2), 43 and Cp(PPh 3 )RuClfadppm)AuCl(3) 43 was prepared by the reaction of CpRuiPPhsXr^-dppnOCl (4) with Pt(COD)Cl 2 , Pd(COD)Cl 2 and Au(PPh 3 )Cl, respectively. All of them possess a dppm linkage between Ru and the second metal center with a threelegged piano stool geometry at Ru (Figure 1).…”

Synthetic, X‐ray Diffraction, Electrochemical, and Density Functional Theoretical Studies of (Indenyl)ruthenium Complexes Containing Dithiolate Ligands

“…However, the dppm equivalent of 4a, that is, [(Ind)-Ru(η 1 -dppm)(η 2 -S 2 CNEt 2 )], was not observed, probably because of thermodynamic instability, though complexes with monodentate dppm are known. [11] Our previous studies showed that the outcome of the reactions of LRu(dppf)Cl [L = Cp (A), HMB (B)] with -S 2 CNEt 2 were very different. For L = Cp, a dinuclear complex [CpRu(S 2 CNEt 2 ) 2 ] 2 (µ-dppf) (C) was formed, and for L = arene, -S 2 CNEt 2 displaced the arene ligand, as it displaced the indenyl ligand in complex 1, as discussed above (see Scheme 4,a,b [3a] ).…”