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

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