Exchange and Spectroscopy of Cationic Rhodium Complexes on Hectorite

Robert A. Schoonheydt, Jozefien Pelgrims, Paul Hendrickx and Johan Luts
Centrum voor Oppervlaktescheikunde en Colloïdale Scheikunde, Katholieke Universiteit Leuven de Croylaan 42, B-3030 Leuven (Heverlee), Belgium

Abstract: The exchange of Rh(NBD)(Pφ3)2+, Rh(NBD)(PMe2φ)3+, Rh(COD)(Pφ3)2+, and Rh(PMe2φ)4+ on hectorite was studied in methanol/dichloromethane, acetone, dimethylformamide, and acetonitrile. At low initial Rh+ concentration and short contact times, ion exchange was the predominant process, and its selectivity and maximum capacity were solvent-dependent. High initial Rh+ concentrations, long contact times, and the most polar solvents favored intersalation and salt precipitation. In all experiments monolayers of complex formed in the interlamellar space and were very tightly held. The complexes retained their integrity on the surface even after removal of all solvent molecules.

Key Words: Catalysis • Cation exchange • Hectorite • Phosphine • Rhodium

Clays and Clay Minerals; June 1984 v. 32; no. 3; p. 185-190; DOI: 10.1346/CCMN.1984.0320305
© 1984, The Clay Minerals Society
Clay Minerals Society (www.clays.org)