Escapade into metal alkoxide chemistry: control of aggregation via oxo andhydroxide ligands

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) so lvates and subsequent non-hydrolytic condensation. Pentanuclear M5O cores d isplay a remarkable stability for large elements and can associate along an edge or an apex. Heteronuclear arrays are thus accessible from these aggre gates by Lewis acid-base reactions or, for a better control of stoichiometr y 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.