A self-catenated rob-type porous coordination polymer constructed from triazolate and carboxylate ligands: fluorescence response to the reversible phase transformation

Abstract

A flexible structure of {[Zn₂(dmtrz)₂(L1)]·6H₂O}_n (MAC-11) (Hdmtrz = 3,5-dimethyl-1H,1,2,4-triazole, H₂L1 = (E)-4,4′-stilbenedicarboxylic acid), which is a self-catenated rob-type net built of two-dimensional [Zn(dmtrz)] layers pillared by L1 ligands, has been solvothermally synthesized. It shows an interesting thermo/water-induced reversible phase transformation accompanied by a photoluminescence response from 418 nm to 453 nm. Based on an iso-framework of {[Zn₂(dmtrz)₂(L2)]·4H₂O}_n (MAC-13, H₂L2 = (E)-azobenzene-4,4′-dicarboxylic acid), a pcu-type framework of {[Zn₂(trz)₂(L1)]·4H₂O}_n (MAC-14, Htrz = 1H, 1,2,4-triazole), and a layered structure of [Zn(dmtrz)(HCOO)], a possible mechanism for the photoluminescence response to the reversible phase transformation for MAC-11 was also proposed.