A series of coordination polymers based on a multidentate N-donor ligand and different polycarboxylate anions: syntheses, structures and photoluminescent properties

Abstract

A series of coordination polymers, namely, [Cd(4,4′-tmbpt)(o-bdc)(H₂O)]·5.25H₂O (1), [Cd(4,4′-tmbpt)(m-bdc)] (2), [Cd(4,4′-tmbpt)(5–OH–bdc)] (3), [Cd₅Na₂(4,4′-tmbpt)₂(btc)₄(H₂O)_3.5]·6.5H₂O (4), [Cd₃(4,4′-tmbpt)(btc)₂(H₂O)₂]·H₂O (5), [Zn(4,4′-tmbpt)(m-bdc)] (6), [Zn₃(4,4′-tmbpt)₂(p-bdc)₃]·5.5H₂O (7), and [Zn₃(4,4′-tmbpt)(btc)₂(H₂O)₂]·H₂O (8), where 4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole, o-H₂bdc = 1,2-benzenedicarboxylic acid, m-H₂bdc = 1,3-benzenedicarboxylic acid, 5–OH–H₂bdc = 5-hydroxy-1,3-benzenedicarboxylic acid, H₃btc = 1,2,3-benzenetricarboxylic acid and p-H₂bdc = 1,4-benzenedicarboxylic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), elemental analyses and powder X-ray diffraction (PXRD) analyses. Compounds 1, 3 and 7 display different 2D → 3D interdigitated structures. Compound 2 shows a 3D 6-connected framework with (4¹²·6³) topology. Compound 4 reveals a 3D (3,4,8)-connected net based on hexanuclear units. Compounds 5 and 8 are isostructural and display 3D (3,9)-connected frameworks based on trinuclear units. Compound 6 exhibits an unusual 2D → 3D polythreaded framework. The structural discrepancies of compounds 1–8 indicate that the presence of the different organic anions play important roles in the formation of the final structures of the coordination polymers. The luminescent properties were also investigated for the compounds 1–8.