Investigation of Mixed Oxidation State Cyanide-Bridged ReVOxo (acac2en/pn) and ReI(bipy)(CO)3 Complexes

A series of cyanide-bridged complexes that combine a low-valent photoacceptor rhenium(I) metal center with an electroactive midvalent rhenium(V) complex were prepared. The synthesis involved the preparation of novel asymmetric rhenium(V) oxo compounds, cis-(ReO)-O-V-(CN)(acac(2)en) (1) and cis-(ReO)-O-V(CN)(acac(2)pn) (2), formed by reacting trans-[(ReO)-O-V(OH2) (acac(2)en)]Cl or trans-(ReO)-O-V(acac(2)pn)Cl with [NBu4] [CN]. The mu-bridged cyanide mixed-oxidation Rev Rei complexes were prepared by incubating the asymmetric complexes, 1 or 2, with fac-[Re-I(bipy)(CO)(3)][OTf] to yield cis-[(ReO)-O-V(acac(2)en)-(mu-CN-1KC:2KN)-fac-Re-I(bipy)(CO)(3)][PF6] (3) and [cis-(ReO)-O-V (acac(2)pn) (mu-CN-1KC:2KN)-fac-Re-I(bipy) (CO)(3)]-[PF6] (4), respectively.