Synthesis,crystal structure,thermal stability,and photoluminescence of a 3-D silver(I) network with twofold interpenetrated dia-f topology

A silver(I) coordination polymer with mixed 3,3′,5,5′-tetramethyl-4,4′-bipyrazole (bpz) and maleic acid, Ag₂(bpz)₃(fum)]_n (1, H₂fum = fumaric acid), was synthesized under hydrothermal condition by in situ isomerization of maleic acid to fumaric acid and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, TGA, and single-crystal X-ray diffraction. The maleic acid in situ isomerizes to fumaric acid and participates in the formation of 1. Topologically, the structure of 1 features a rare 3-connected twofold interpenetrated dia-f net with a point symbol of {4.14²}. Compound 1 exhibits photoluminescence in the solid state with an emission maximum at 470 nm upon excitation at 365 nm at room temperature, which is attributed to intraligand or/and interligand π → π* transition.