Crystal engineering towards the luminescence property trimming of hybrid coordination polymers

Abstract

In this work, we report the synthesis, structures and luminescence properties of two pairs of isostructural coordination polymers [Cu(mttz)] (1) and [Cu(ettz)] (3); [Cu₂(mttz)Cl] (2) and [Cu₂(ettz)Cl] (4) (Hmttz = 5-(methylthio)-1H-tetrazole, Hettz = 5-(ethylthio)-1H-tetrazole). Structural analysis reveals that compounds 1 and 3 exhibit two dimensional (2D) layered structures, which are constructed by two types of one dimensional (1D) chains. Compounds 2 and 4 consist of 1D strip-like chains, which are further assembled into three dimensional (3D) frameworks. Detailed luminescence investigation displays that compound 1 consists of a main peak at 454 nm and a shoulder peak at 585 nm, similar to the luminescent emission of Hmttz ligand (461, 554 nm), whereas compound 2 displays one emission band centered at 475 nm. A similar luminescence phenomenon has also been observed between 3, 4 and Hettz ligand. In the present system, the rigidity, arrangement and hydrogen bonding of ligands in the title compounds play an important role leading to luminescence property trimming.