Metalloaromaticity

Metalloaromaticity is the manifestation of aromatic properties in the chelate metallacycle, and was first described by Calvin and Wilson in 1945. The subject has received sporadic interest until recently, mainly due to the vagueness of the term, 'aromaticity.' In the past decade, there has been renewed interest in the concept due to advances in synthesis, theory and the recognition of its importance in reaction mechanisms. The concept is useful in that it unifies the reactivity, magnetic, spectroscopic and structural properties of chelates in terms of the Huckel rule. This review stems from my graduate work with Dr A.B.P. Lever, in which I began to holistically understand the properties of alpha,alpha'-diimine complexes in the context of metalloaromaticity. Others had thought along similar lines, and it is the goal of this review to present these perspectives. (C) 2001 Elsevier Science B.V. All rights reserved.