Escapade into Metal Alkoxide Chemistry: Control of Aggregation Via Oxo and Hydroxide Ligands

Abstract

The high coordination numbers required by large elements (Ln, Ba...) favor the formation of closo oxo aggregates by desolvation of M(OR)_n(ROH)_x solvates and subsequent non-hydrolytic condensation. Pentanuclear M₅O cores display a remarkable stability for large elements and can associate along an edge or an apex. Heteronuclear arrays are thus accessible from these aggregates by Lewis acid-base reactions or, for a better control of stoichiometry between the metals, by reactivity of the coordinated alcohol of a solvate. Functionalisation by polymerisable O-donors such as allylacetatoacetate (HAAA) provides species which can be converted into organic-inorganic arrays by copolymerisation reactions.

Keywords::

• metal alkoxides
• clusters
• polymerisable ligands
• sol-gel
• organic-inorganic