ADSORPTION OF MONONUCLEAR, BINUCLEAR, AND POLYMERIC RUTHENIUM COMPLEXES ON MICA

Mononuclear, binuclear, and polymeric ruthenium(II) complexes with 2,2 '-bipyridine (bipy) and tetrapyridophenazine (tppz) ligands were adsor bed via ion exchange onto an ultrahigh-surface-area mica with exchange able lithium surface ions. The adsorption isotherms were measured. The ion exchange isotherms and desorption experiments show that the affin ity of the complexes to mica is higher than that of lithium or potassi um ions. The surface ion exchange capacities were determined and the s pace requirements of the complexes on the mica surface were calculated . These requirements depend on the ligands. For all the complexes stud ied, the large dimensions of the complexes did not permit a complete e xchange of the surface lithium ions. For the initial part of the isoth erm, it could be demonstrated that adsorption of the complexes was acc ompanied by the release of two lithium ions per ruthenium ion. The exp erimentally determined space requirements of the ions were in reasonab le agreement with those estimated by computer modeling. From UV-vis me asurements, it appears that, depending on the complex, the ligand sphe re is distorted upon adsorption. (C) 1997 Academic Press.