Crystal Structure of Coordination Polymers Based on Scandium and 2,5-Pyrazinedicarboxylic Acid

Abstract

In the interaction of scandium chloride hexahydrate and 2,5-pyrazinedicarboxylic acid (H₂pzc) dihydrate in different solvent mixtures two novel coordination polymers are obtained under solvothermal conditions: [Sc₂(dmf)₂(H₂O)₂(pzc)₃] (1) and [Sc₂(H₂O)₂(pzc)₃]·2CH₃CN·H₂O (2) (dmf is N,N-dimethylformamide). Crystal structures of compounds 1 and 2 are determined by single crystal X-ray diffraction and supported by elemental and thermogravimetric data and IR spectroscopy. The phase purity of the samples prepared is confirmed by powder X-ray diffraction. It is shown that the coordination environment of the scandium cation and the 2,5-pyrazinedicarboxylate ligand denticity change depending on the composition of a solvent mixture. Compound 1 has a layered structure while in the structure of 2 there is a three-dimensional framework.