Zinc Metal-Organic Coordination Polymer with 4,7-di(1,2,4-triazol-1-yl)-2,1,3-Benzothiadiazole and 1,4-Naphthalene Dicarboxylic Acid: Luminescent Properties and Guest–Host Charge Transfer

Metal-organic coordination polymer {[Zn₇O₂(tr₂btd)₂(1,4-ndc)₆]·2tr₂btd}_n representing an inclusion compound of free ligand molecules in the pores of the 3D framework is synthesized by the interaction of zinc 4,7-di(1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole (tr₂btd) nitrate and 1,4-naphthalene dicarboxylic acid (1,4-H₂ndc). Features of the interaction of guest molecules with the framework are investigated by single crystal X-ray diffraction, IR spectroscopy, and quantum chemical calculations. The study of the luminescent properties of compounds shows a bathochromic shift of the emission maximum that is unusual for coordination polymers with tr₂btd as a linker. Quantum chemical calculations at the density functional theory level reveals charge transfer between the guest molecule and the framework during emission.