Three Scandium Compounds with Unsaturated Coordinative Metal Sites – Structures and Catalysis

Two scandium coordination polymers, a 2D supermolecule structure {[Sc(OH)(L1)2(H2O)]}n (1) (HL1 = isonicotinic acid), a 1D infinite chain structure {[Sc3(L2)4(H2O)4]·NO3·H2O}n (2) (H2L2 = 4,5-imidazole dicarboxylic acid), as well as a scandium complex {[Sc2(OH)2(L3)2(H2O)4]}n (3) (H2L3 = 1,2,3-triazole-4,5-dicarboxylic acid), were synthesized and characterized by X-ray crystallography. Compounds 1-3 are active heterogeneous catalysts for high-yield cyanosilylation of aromatic aldehydes in acetonitrile, particularly for p-nitrobenzaldehyde. Moreover, these three catalysts can be reused three times without significant loss in activity or mass.