Journal of Colloid and Interface Science, Vol.189, No.2, 305-311, 1997
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 adsorbed via ion exchange onto an ultrahigh-surface-area mica with exchangeable lithium surface ions. The adsorption isotherms were measured. The ion exchange isotherms and desorption experiments show that the affinity of the complexes to mica is higher than that of lithium or potassium ions. The surface ion exchange capacities were determined and the space requirements of the complexes on the mica surface were calculated. These requirements depend on the ligands. For all the complexes studied, the large dimensions of the complexes did not permit a complete exchange of the surface lithium ions. For the initial part of the isotherm, it could be demonstrated that adsorption of the complexes was accompanied by the release of two lithium ions per ruthenium ion. The experimentally determined space requirements of the ions were in reasonable agreement with those estimated by computer modeling. From UV-vis measurements, it appears that, depending on the complex, the ligand sphere is distorted upon adsorption.