Analysis and Isolation of Cationic Rhenium(I) and Ruthenium(II) Multinuclear Complexes Using Size-exclusion Chromatography

Various cationic rhenium(I) and ruthenium(II) mono- and multinuclear complexes were successfully separated by size-exclusion chromatography (SEC), using a 50:50 (v/v) mixture of methanol and acetonitrile with CH3CO2NH4 as an eluent. The logarithms of the molecular weights were accurately linear in the distribution coefficients: for linear-shaped rhenium(I) multinuclear complexes, log M(W) = -2.86K(SEC) + 5.24 (r = -0.990 and n = 15); for ring-shaped rhenium(I) multinuclear complexes, log M(W) = -2.94K(SEC) + 5.40 (r = -0.999; n = 5); for bimetallic complexes including ruthenium(II), log M(W) = -0.40K(SEC) + 3.37 (r = -0.959; n = 6). This separation method is applicable to the preparative-scale separation of cationic multinuclear complexes from a mixture.