Discrete Octamer Water Cluster and 1D T5(2) Water Tape Trapped in Two Luminescent Zn(II)/1,2-Bis(imidazol-1′-yl)ethane/Dicarboxylate Hosts: From 2D (4,4) Net to 3D 5-Fold Interpenetrated Diamond Network

Abstract

Two new mixed-ligand Zn(II) coordination polymers, namely, [Zn(bime)(glu)·4H2O]n (1) and [Zn(bime)(sub)·3H2O]n (2) (bime = 1,2-bis(imidazol-1′-yl)ethane, H2glu = glutaric acid, H2sub = suberic acid), have been synthesized and structurally characterized. Complex 1 exhibits a wavy two-dimensional (2D) sheet with (4,4) topology. Complex 2 is a three-dimensional (3D) framework with 5-fold interpenetrated diamond topology. Of particular interest, a discrete octamer water cluster comprised of a chairlike hexamer water cluster with two extra water molecules dangling on two diagonally vertices of the chair was observed in the grid of the 2D sheet of 1. In 2, a 1D infinite T5(2) water tape constructed from edge-sharing pentamer water clusters accommodates in the channels of the 3D network. The results suggest that the dicarboxylates play crucial roles in the formation of the different host structures as well as different guest water aggregations. Additionally, the thermal stabilities and photoluminescence spectra of them were discussed.