Copper dimethylmalonate coordination polymers with 4,4′-bipyridine coligands: Kinetic and thermodynamic products with different dimensionalities

Slow diffusion of an ethanolic solution of 4,4′-bipyridine (bpy) into an aqueous solution of copper dimethylmalonate (dmmal) afforded two different coordination polymer complexes as time elapsed. These were structurally characterized via single-crystal X-ray diffraction. A small amount of light blue crystals of {[Cu2(dmmal)2(bpy)1.5(H2O)]·2H2O}n (1) were initially deposited at the solution interface. Compound 1 displays a 3,4-connected 2D layer with an unprecedented (426)(42638) topology comprising alternating rows of hexagonal and rectangular circuits. These crystals dissolved as the reaction continued, with dark blue crystals of {[Cu3(dmmal)3(bpy)3(H2O)4]·H2O}n (2) forming at the bottom of the reaction vessel. Compound 2 manifests a 4-connected self-penetrated 658 cds topology. Thermal properties of 2 are also reported.