A CYCLIC VOLTAMMETRIC STUDY OF IRON(II) RUTHENIUM(II) COMPLEXES WITH BIS(TERTIARY PHOSPHINES)/

Nine complexes of Fe-II/Ru-II with bis(tertiary phosphines), namely, 1 ,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(diphenylphosphino)ethy lene (dppen) and o-phenylenebis(diphenylphosphine) (o-diphos) were stu died using cyclic voltammetry. The half-wave potentials for the comple xes studied are: (1) [FeCl2(dppe)], 0.050 V; (2) [Fe(NCS)(2)(dppe)(2)] , 0.265 V; (3) [RuCl2(dppe)(2)], 0.548 V; (4) [FeCl2(dppen)(2)], 0.225 V; (5) [Fe(NCS)(2)-(dppen)(2)], 0.290 V; (6) [RuCl2(dppen)(2)], 0.690 V; (7) [FeCl2(o-diphos)(2)] 0.160 V; (8) [Fe(NCS)(2)(o-diphos)(2)] 0. 582 V; and (9) [RuCl2(o-diphos)(2)], 0.265 V. The redox potentials are related to the nature of the ligand, the nature of the metal, the ste reochemistry of the complex and the ligand held strength.