Metal reactivity on oxo surfaces modeled by calix[4]arenes: Metal-driven reactions in an oxo-quasiplanar environment

A quite recent molecular approach to metal-oxo surfaces uses as a model the preorganised O-4 set of donor atoms derived from the calix[4]arene tetraan ion and its alkylated forms. Metals bonded to such an environment assist: 1 ) the formation of C-C and C=C bonds by multiple migratory insertion reacti ons; 2) olefin rearrangement to M-C, M=C, M=C occurring under very mild con ditions; 3) the activation and reduction of dinitrogen with a complete N=N triple bond cleavage.