A series of Zn(ii) and Cd(ii) coordination compounds based on 4-(4H-1,2,4-triazol-4-yl)benzoic acid: synthesis, structure and photoluminescence properties

Abstract

Seven coordination compounds, namely [Zn(4-tba)₂(H₂O)₂] (1), [Zn(4-tba)Cl]·CH₃OH (2), [Zn(4-tba)₂] (3), [Zn(4-tba)₂]·DMA·3.5H₂O (4), [Cd(4-tba)₂]·DMF·3.6H₂O (5), [Cd(4-tba)₂] (6) and [Cd₅Cl₄(4-tba)₆]·1.5DMF·4H₂O (7) (4-Htba = 4-(4H-1,2,4-triazol-4-yl)benzoic acid, DMA = N,N-dimethylacetamide and DMF = N,N-dimethylformamide), have been synthesized under hydro/solvothermal conditions by using a triazolate–carboxylate bifunctional organic ligand, 4-Htba. Complexes 1 and 2 exhibit a mononuclear motif and a two-dimensional (2D) network with sql topology, respectively, whereas 3–6 display different interpenetrating structures. Compound 3 shows a 2-fold interpenetrating 2D net with sql topology, 4 and 5 display uninodal 4-connected 4-fold interpenetrating 3D nets with dia (6⁶) topology belonging to class Ia and class IIIa, respectively, and compound 6 exhibits a 5-fold interpenetrating dia net. Complex 7 exhibits a non-interpenetrating 3D framework constructed from decanuclear cadmium–chloride chain units and 4-tba ligands with various coordination modes. All the complexes were characterized using single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectroscopy and elemental analyses. In addition, the thermogravimetric analysis and solid-state photoluminescence results for 1–7 were also investigated.