Elaboration of hybrid nanocluster materials by solution chemistry

The [(M6L12i)L6a]n− and [(M6L8i)L6a] units (a = apical, i = inner) constitute the basic building blocks in the octahedral cluster chemistry. Nano-sized metallic clusters are easily obtained by solid state synthesis with transition elements associated with halogen or chalcogen. The intrinsic properties of M6 cluster units-one or two electron reversible redox process, magnetism and luminescence-depend on the nature of the metal and ligands. The solubilisation of M6 solid state compounds provides [(M6L12i)L6a]n− or [(M6L8i)L6a]n− building blocks with individual properties that can be further used for the design of hybrid organic/inorganic materials. Several examples of solid state precursors are presented as well as substitution reactions of apical ligands in solution. Indeed, hexacyano M6 clusters are obtained by direct reaction of solid state precursors in aqueous KCN solutions. Low dimensional frameworks are subsequently obtained by recrystallisation of hexacyano M6 clusters with transition elements. The functionalisation of cluster proceeds in two steps. The first one consists in the replacement of apical halogens of cluster unit precursors by labile groups as CF3SO3 (triflate) or solvent molecules after solution reaction. The second one consists in the substitution of the labile groups by functionalised phenolate or pyridine ligands.