Ru(II) complexes with the ligand 1,2-ds(diphenylphosphino)ethylene: Chemical and electrochemical synthesis, characterization and x-ray structure

Article abstract of DOI:10.1016/s0020-1693(96)05439-4

The synthesis of [RuL₁L₂(dppen)₂], where L₁ = L₂ = Cl (I); L₁ = H, L₂ = Cl (II); [HRuCO(dppen)₂] (PF₆) (III), is described. The cis- and trans-[RuCl₂(dppen)₂] (dppen = 1,2-cis(diphenylphosphino)ethylene) isomers have been chemically synthesized using the [RuCl₂(PPh₃)₃] precursor. Furthermore, these isomers were obtained by exhaustive controlled potential coulometry, starting from the trans-hydride [HRuCl(dppen)₂] complex in dichloromethane. The trans-[RuCl₂(dppen)₂] species can also be obtained by electrochemical transformation from the cis isomer, with the oxidized intermediate trans-[RuCl₂(dppen)₂]⁺ detected by EPR measurements and cyclic voltammetry. All complexes herein described were fully characterized by spectroscopic techniques. Crystals of trans-[RuCl₂(dppen)₂] were obtained from dichloromethane/hexane and its X-ray structure determined. The crystals belong to the monoclinic space group P2₁/c, a = 11.480(2), b = 13.061(2), c = 17.500(3) ?, β = 95.28(1)°, and the structure was solved by conventional heavy atom methods and refined by full-matrix least-squares procedures to R = 0.059 from 2720 reflections with 1 ≥ 3σ(I).