An eight-connected metal organic framework based on Cu5 clusters: Synthesis, structure, magnetic and catalytic properties

摘要

A reaction of copper acetate,5-nitroisophthalic acid in a water-methanol mixture under solvothermalcondition results in a new metal-organic framework compound, [Cu5(μ3-OH)2(H2O)6{(NO2)-C6H3-(COO)2}4].5H2O,(1). The compound contains Cu5pentameric cluster units connected by 5-nitro isophthalate (NIPA) moietiesforming a CdCl2-like layer, which are further connected by anotherNIPA moiety forming the three-dimensional structure. The water molecules in (1) can be reversibly adsorbed. Theremoval of water accompanies a change in the colour as well as a structuralre-organization. Magnetic studies suggest strong antiferromagnetic correlationsbetween the Cu5 cluster units. The compound (1) exhibits heterogeneous Lewis acid catalysis for thecyanosilylation of imines with more than 95 % selectivity. Compound (1) has been characterized by IR,UV-vis, TGA, powder XRD studies.