Monomeric and dimeric Re(I)(tricarbonyl)(8-quinolinato) complexes

A simple synthetic procedure (reaction between Re(CO)(5)Cl and 8-hydroxyquinoline, HOX, in boiling toluene) leads to the dimeric complex Re-2(CO)(6)(OX)(2). In coordinating solvents Re-2(CO)(6)(OX), undergoes dissociative solvolysis (via a second order reaction) to form monomeric species of general formula Re(CO)(3)(OX)solv. In non-coordinating media, however, the dimeric complex remains unaffected. Molecular structures of both forms (which are in accord with IR absorption spectra) were confirmed by means of X-ray measurements. UV-VIS spectroscopic (absorption and emission) properties of both newly synthesized Re(I) complexes, have been investigated and the differences in their luminescence properties have been briefly discussed.