Carborane-Stabilized Mixed-Valence Metallooligomers

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

This award in the Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research by Russell N. Grimes, Chemistry Department, University of Virginia, on mixed-valence metallo-carboranes. Selected families of dinuclear and polynuclear transition metal metallacarboranes will be synthesized. These are soluble paramagnetic complexes featuring two or more transition metal-carborane units connected by covalently bonded linkers designed to permit intramolecular metal-metal communication. Small carborane ligands will be used to stabilize the complexes, permitting directed synthesis of a range of molecular architectures in stable, soluble form. The primary goal is to explore the dependence of metal-metal communication on structural geometry, choice of metals and metal oxidation states, the number and nature of the linkers, and the mode of binding of the linking groups to the metallacarborane cluster units. The architectures to be investigated are chains with metals at the ends, internally metallated linear systems, and branched chain compounds. The connectors will include alkynyl, alkenyl, and phenylene units. The compounds will be characterized by a variety of methods, including X-ray diffraction, EPR, NMR, and cyclic voltammetry. New synthetic methods will be developed to obtain compounds with specific architectural designs. These compounds obtained will be used to explore interaction between metals in systems that contain metals that have a mixture of oxidation states. The results will be relevant to design of materials with specified electronic, magnetic, or optical properties. Graduate students will receive training in a variety of advanced methods and challenging synthetic work.