The M-C bond functonalities bonded to an oxo-surface modeled by calix[4]arenes

This chapter reviews the potential of calix [4] arenes as ancillary ligands in coordination and organometallic chemistry of transition metals, in the areas of both metal reactivity and catalysis. Therefore, the metalation of calix [4] arenes and their O-alkylated derivatives is focused, only when it produces compounds potentially useful for exploring the chemical reactivity of the metal centers. The chemistry associated with the metal-oxo-surfaces modeled by the metallacalix [4] arene at the molecular is reviewed. In the metalla-derivatives, calix [4] arenes exclusively assume the cone conformation, thus keeping the oxygen set quasi-planar. They usually act as tetra-anionic ligands, though the charge of the O4set can be tuned by a different degree of alkylation. The metal-oxo molecular models outlined in the chapter have a potential for studying the metal activity in a quite unusual environment. Some of the possibilities could be the generation and the chemistry of M––C, M=C, M≡C functionalities; the interaction with alkenes, alkynes, hydrocarbons, and hydrogen; the activation of small molecules, such as N26and CO; the support of metal–metal bonded functionalities; and the generation of highly reactive low-valent metals. © 2001, Elsevier Inc. All rights reserved.