Construction of Co(II), Cu(II), and Zn(II) coordination compounds driven by a pyridine-dicarboxylic acid: Hydrothermal assembly, structural and topological versatility, and catalytic properties

Abstract

A derivative of pyridine-dicarboxylic acid, 5-(3-carboxyphenyl)picolinic acid (H2cpic), was used as a versatile building block to synthesize a series of five novel coordination compounds under hydrothermal conditions and formulated as {[Cu2(μ-cpic)2(phen)]·H2O}n (1), [Co(μ-cpic)(phen)(H2O)]n (2), [Cu2(μ-cpic)2(2,2′-bipy)(H2O)2]·2H2O (3), {[Cu3(μ-cpic)3(μ-4,4′-bipy)1.5(H2O)3]·2H2O}n (4), and {[Zn2(μ-cpic)2(μ-dpe)0.5(H2O)3]·H2O}n (5). The auxiliary ligands used in the synthesis were 1,10-phenanthroline (phen), 2,2′-bipyridine (2,2′-bipy), 4,4′-bipyridine (4,4′-bipy), and 1,2-di(4-pyridyl)ethylene (dpe). The structures of the compounds 1–5 vary significantly, ranging from a 0D tetramer (3) to 1D metal–organic chains (1, 2, 4, and 5). Furthermore, these compounds were evaluated as heterogeneous catalysts for the Henry reaction, achieving high product yields under optimized conditions. We further investigated various reaction parameters, and substrate scope, and assessed the feasibility of catalyst recycling. This thorough investigation highlights the versatility of H2cpic as a dicarboxylate building block in the formation of functional coordination polymers