Sc2(pydc)2 unit based 1D, 2D and 3D metal–organic frameworks as heterogeneous Lewis acid catalysts for cyanosilylation

Three scandium metal–organic frameworks (Sc-MOFs), [Sc(pydc)(Hpydc)(H2O)]·H2O (1), [Sc2(pydc)3(H2O)4]·5H2O (2) and [Sc(pydc)(H2O)(NO3)] (3) with similar Sc2(pydc)2 building unit were prepared by using 2,3-pyridinedicarboxylic acid (H2pydc) ligand under hydrothermal conditions. Compound 1 exhibits a ladder-shaped chain with Sc2(pydc)2 units, which further construct a supramolecular characteristic with water molecules via hydrogen bond. Compound 2 features a waved layer made up of pydc2− ligands and two types of crystallographically different Sc(III) ions, among which Sc2 and pydc2− ligands constructed the Sc2(pydc)2 units. In compound 3, left and right helixes were alternately linked by the Sc2(pydc)2 units forming a hexagonal network with nbo-a topology. All the prepared compounds present effective heterogeneous Lewis acid catalytic functionality for the cyanosilylation of aldehyde.