Interconvertible structural transformations between two Zn(II) interpenetrating coordination polymers

Abstract

Two distinct Zn(II) coordination polymers (CPs) have been prepared based on Zn(NO3)2 and 4-(2-ethyl-1H-imidazol-1-yl)benzoic acid (2-Heiba) via different synthetic approaches, solvothermal synthesis and layer diffusion, respectively. Upon solvothermal condition, a 2D undulated CP [Zn2(2-eiba)3(OH)]n (1) can be obtained, which incorporates the polythreading structural motifs and then results in the 3-fold pcu topological network with the aid of interlayer OH⋯N hydrogen bonds. Employment of layer diffusion method affords another 3D CP {[Zn(2-eiba)2](H2O)3}n (2), featuring a dia topological network in 2+2→4-fold interpenetrating pattern. Interestingly, interconvertible structural transformations between 1 and 2 can be achieved by immersing in CH3OH-H2O solution under stirring or solvothermal conditions, respectively. In addition, thermal stability and fluorescence properties of these complexes have also been studied.