Structural modulation and properties of four cadmium(ii) coordination architectures based on 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole and aromatic polycarboxylate ligands

Abstract

By using a multidentate N-donor tecton 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (Hppt) and different aromatic polycarboxylates, including terephthalic acid (H₂tp), isophthalic acid (H₂ip), 1,3,5-benzenetricarboxylic acid (1,3,5-H₃btc), and 1,2,4,5-benzenetetracarboxylic acid (1,2,4,5-H₄btec), four cadmium(II) coordination polymers {[Cd(ppt)(tp)_0.5(H₂O)₂]·H₂O}_n1; {[Cd₃(ppt)₂(ip)₂(H₂O)]·H₂O}_n2; [Cd₂(ppt)(btc)(H₂O)₄]_n3; {[Cd₃(ppt)₂(btec)(H₂O)₃]·(H₂O)₃}_n4 have been synthesized under solvothermal conditions. Complex 1 shows a new 2D two-fold interpenetrating brick wall plane with 3-connected net. Complex 2 features a 3D net with a rare (3,4,5)-connected topology net. Complex 3 is an intriguing two-fold interpenetrating 3D framework, which shows four nodal 3-connected topology with the Schläfli symbol of (7²·9)(8²·8)(6·7·9)(5²·7). Complex 4 exhibits a 3D (4,6)-connected (4⁴·6¹⁰·8)(4⁴·6²) net. In addition, the thermal stability and photoluminescence properties of 1–4 and the Hppt ligand in the solid state have also been studied in detail.