New methacrylate-functionalized ba and ba-ti oxoclusters as potential nanosized building blocks for inorganic-organic hybrid materials: synthesis and characterization.

Two different methacrylate modified barium-titanium and barium-based oxoclusters, Ba2Ti10(mu3-O)8(mu2-OH)5(mu2-OMc)20(OiPrOMe)2 (1) and [Ba(OMc)2(McOH)3]n (2), were synthesized by reacting methacrylic acid with barium-titanium and barium-zirconium double alkoxides, respectively. The X-ray structure determination of oxocluster 1 shows a core consisting of a ring of 10 titania octahedra, sharing corners, that surround the two barium oxygen decaeders which are linked by common edges to the titania octahedra and the neighboring barium decaeder. The solid-state structure of 2 consists of zigzag chains of edge-sharing {BaO9} polyhedra linked through bridging bidentate metacrylate anions, displaying different coordination mode of carboxylate groups. The presence of methacrylate groups surrounding the two polynuclear compounds has been exploited for the embedding of the oxocluster in inorganic-organic hybrid materials, and some preliminary results are presented.