Metal(Ii) coordination polymers from tetracarboxylate linkers: Synthesis, structures, and catalytic cyanosilylation of benzaldehydes

Abstract

Three 2D coordination polymers, [Cu2(μ4‐dpa)(bipy)2(H2O)]n∙6nH2O (1), [Mn2(μ6‐ dpa)(bipy)2]n (2), and [Zn2(μ4‐dpa)(bipy)2(H2O)2]n∙2nH2O (3), were prepared by a hydrothermal method using metal(II) chloride salts, 3‐(2′,4′‐dicarboxylphenoxy)phthalic acid (H4dpa) as a linker, as well as 2,2′‐bipyridine (bipy) as a crystallization mediator. Compounds 1–3 were obtained as crystalline solids and fully characterized. The structures of 1–3 were established by single‐crystal X‐ ray diffraction, revealing 2D metal–organic networks of sql, 3,6L66, and hcb topological types. Thermal stability and catalytic behavior of 1–3 were also studied. In particular, zinc(II) coordination polymer 3 functions as a highly active and recoverable heterogeneous catalyst in the mild cyanosilylation of benzaldehydes with trimethylsilyl cyanide to give cyanohydrin derivatives. The influence of various parameters was investigated, including a time of reaction, a loading of catalyst and its recycling, an effect of solvent type, and a substrate scope. As a result, up to 93% product yields were attained in a catalyst recoverable and reusable system when exploring 4‐ nitrobenzaldehyde as a model substrate. This study contributes to widening the types of multifunctional polycarboxylic acid linkers for the design of novel coordination polymers with notable applications in heterogeneous catalysis.