MANGANESE CARBOXYLATE CLUSTERS - FROM STRUCTURAL AESTHETICS TO SINGLE-MOLECULE MAGNETS

An overview is provided of some recent developments in manganese carbo xylate cluster chemistry. A variety of synthetic methodologies are des cribed together with the structures of the resultant products, which s pan metal nuclearities of 4 to 18 and oxidation states of II to IV, in cluding mixed-valency. The spins of the ground states of these product s are often large and sometimes abnormally large, and in certain cases when this is coupled to a sufficiently large magnetoanisotropy, the d usters function as single-molecule magnets i.e., they can be magnetize d by an external magnetic field below a critical temperature. These co mplexes display hysteresis in magnetization vs, magnetic field studies , and clear evidence for quantum tunnelling of magnetization. Such res ults establish single-molecule magnetism as a new magnetic phenomenon, and one that holds great promise for next-century technological appli cations. (C) 1998 Elsevier Science Ltd. All rights reserved.