Metal Complexes in Micellar and Liquid Crystalline Solutions

Abstract

Metal complexes in colloidal solutions have shown a variety of characteristic features and have potential functionalities. The current chapter focuses on the ion–ion and ion–solvent interactions in metal-containing micellar and liquid crystalline solutions. Cobalt(iii) and chromium(iii) complexes offer a variety of tripositive ions, so that we can observe strong ionic interactions between the metal complex ions and ionic surfactants in the colloidal solutions. Multinuclear NMR spectroscopy is a powerful tool for the studies of multicomponent aggregation systems because of the high receptivity and high selectivity to the environment around the observed nucleus. Specific interactions of metal ions in colloidal solutions are particularly enhanced in the systems where metal ions highly condense in aggregation solutions such as micelles, microemulsions, and liquid crystalline solutions composed of amphiphilic metal complexes, i.e. metallosurfactants. In the latter half of this chapter, a variety of unique molecular assemblies of metallosurfactants are reviewed and it is shown that they arise from the characteristic molecular structures, which are unattainable in conventional organic surfactants.