Polymeric, Mixed-Valence Transition Metal Compounds

In our work we have prepared and characterized materials in which metal atoms or ions are held in close proximity by chemical linkages. One of our goals has been to establish the chemical and physical properties which arise from metal-metal interactions in such systems and to modify the properties in a controlled way by directed chemical synthesis. Three different kinds of systems have been studied which differ with regard to the nature of the metal-metal interaction: 1. Compounds in which there is strong, direct metal-metal bonding. 2. Cases where there are strong metal-metal interactions through bridging ligands. 3. Cases where there are weak metal-metal interactions through bridging ligands. In compounds containing strong metal-metal bonds, the effect of the metal-metal bond(s) is to modify strongly the chemical and electronic properties of the compounds when compared to the component monomers.( 1 ) One of the intriguing properties of such systems is that if certain