Linkage isomerism for 4-methylimidazole and a new coordination mode of pyrazine-2,3-dicarboxylate ligand in {[Cd(pzdc)(4-mim)(5-mim)2]·½H2O}n coordination polymer

Syntheses, supramolecular networks and Hirshfeld surface and thermal analyses of two new cadmium chloride coordination polymers with an N,O-chelating ligand

Two new coordination polymers, namely poly[[(3-aminopyrazin-4-ium-2-carboxylate-κ²N¹,O)di-μ-chlorido-cadmium(II)] monohydrate], {[CdCl₂(C₅H₅N₃O₂)]·H₂O}_n, (1), and poly[2-amino-3-carboxypyrazin-1-ium [(3-aminopyrazine-2-carboxylato-κ²N¹,O)di-μ-chlorido-cadmium(II)] monohydrate], {(C₅H₆N₃O₂)[Cd(C₅H₄N₃O₂)Cl₂]·H₂O}_n, (2), have been synthesized from the reaction of cadmium(II) chloride and 3-aminopyrazine-2-carboxylic acid (Hapca) under mild conditions in acidic media. The two coordination polymers have been characterized by single-crystal X-ray diffraction and show chloride-bridged zigzag chains with octahedrally coordinated metal ions, where Hapca acts as a bidentate ligand via the π-conjugated N atom and a carboxylate O atom. The chains are further interconnected via noncovalent interactions into three-dimensional supramolecular networks. The dominant H...O and H...Cl interactions for both compounds were quantified using Hirshfeld surface analysis. The thermal stability and topological analysis of the two-dimensional networks of (1) and (2) are also discussed.

Pyrazine dicarboxylate-bridged arsenotungstate: synthesis, characterization, and catalytic activities in epoxidation of olefins and oxidation of alcohols

The catalytic properties and polyanionic structure of pyrazine dicarboxylate-bridged arsenotungstate are reported.