Alkylaluminum, -gallium, -magnesium, and -zinc monophenolates with bulky substituents
AbstractThe bulky phenols 2,6-Ad2C6H3OH (Ad=adamantyl), A, (2,6-Ph2CH)2-4-Me-C6H2OH, B, and (2,6-Tol2CH)2-4-iPr-C6H2OH, C, react with one equivalent of Et3M (M=Al, Ga), Bu2Mg and Et2Zn to afford well-defined mono-phenolate complexes (ArOMRn)m. The aluminum and gallium phenolates derived from the very bulky phenol A are likely monomeric in the solid state. The other compounds are dimeric with bridging phenolates. Crystal structures of compounds with phenols B and C display the dimeric M2O2 cores of the phenolates and illustrate some deviations for the magnesium and zinc compounds. The former possesses stabilizing Mg···C contacts with one of the flanking arene groups of the phenolate substituent, and the latter may be viewed as an intermediate between a symmetric dimer and two monomers. All compounds were characterized by 1H and 13C NMR spectroscopy, and their solution spectra are in agreement with the crystal structure data.
Landolt–Börnstein. Numerical data and functional relationships in science and technology. Group III.Crystal and solid state physics. Vol. 7.Crystal structure data of inorganic compounds. Parteby W. Pies and A. Weiss