Sc2(pydc)2 unit based 1D, 2D and 3D metal-organic frameworks as heterogeneous Lewis acid catalysts for cyanosilylationElectronic supplementary information (ESI) available: Selected bond lengths and angles, hydrogen bonding, additional figures for crystal structures, PXRD, IR and TGA. CCDC 976321-976323. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt03221g

Three scandium metal-organic frameworks (Sc-MOFs), [Sc(pydc)(Hpydc)(H 2 O)]·H 2 O ( 1 ), [Sc 2 (pydc) 3 (H 2 O) 4 ]·5H 2 O ( 2 ) and [Sc(pydc)(H 2 O)(NO 3 )] ( 3 ) with similar Sc 2 (pydc) 2 building unit were prepared by using 2,3-pyridinedicarboxylic acid (H 2 pydc) ligand under hydrothermal conditions. Compound 1 exhibits a ladder-shaped chain with Sc 2 (pydc) 2 units, which further construct a supramolecular characteristic with water molecules via hydrogen bond. Compound 2 features a waved layer made up of pydc 2− ligands and two types of crystallographically different Sc( iii ) ions, among which Sc2 and pydc 2− ligands constructed the Sc 2 (pydc) 2 units. In compound 3 , left and right helixes were alternately linked by the Sc 2 (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. Three new Sc-MOFs have been synthesized using H 2 pydc linker and Sc( iii ) ions. 1 features a ladder-shaped chain, 2 displays a waved layer and 3 exhibits a (3,3)-connected nbo-a network. All three compounds exhibit good catalytic abilities for the cyanosilylation of aldehyde.