A new 2D coordination polymer from 3-(1,2,4-triazolyl-4-yl)-1H-1,2,4-triazole: Hydrothermal synthesis, structure, and fluorescence

A series of hydrothermal reactions of ZnX2 (image, and CH3COO−) with 3-(1,2,4-triazolyl-4-yl)-1H-1,2,4-triazole (Htrtr) with various Zn–Htrtr ratios led to the same 2D metal–organic coordination polymer [Zn(trtr)2]n (1), which features a 2D grid. Four trtr− ligands adopting μ2-1κN: 1′κN mode alternately connect four Zn1 centers to form a 28-membered ring. The growth of the 28-membered rings fuses into the 2D grid, thus, to be further fabricated into a supramolecular framework by hydrogen bondings. The fluorescence of 1 shows an emission peak at 424 nm, which can be assigned to intra-ligand π–π∗ transition of trtr.