Electron Transfer from Hexameric Copper Hydrides

The octahedral core of 84-electron
LCuH hexamers does not dissociate
appreciably in solution, although their hydride ligands undergo rapid
intramolecular rearrangement. The single-electron transfer proposed
as an initial step in the reaction of these hexamers with certain
substrates has been observed by stopped-flow techniques when [(Ph3P)­CuH]6 is treated with a pyridinium cation. The
same radical cation has been prepared by the oxidation of [(Ph3P)­CuH]6 with Cp*2Fe+ and
its reversible formation observed by cyclic voltammetry; its UV–vis
spectrum has been confirmed by spectroelectrochemistry. The 48-electron
trimer [(dppbz)­CuH]3 has been prepared by use of the chelating
ligand 1,2-bis­(diphenylphosphino)­benzene (dppbz).