Three 3D Cu(II) coordination polymers constructed from 1,2,4,5-benzenetetracarboxylate acid and three positional isomeric ligands

Based on 1,2,4,5-benzenetetracarboxylate acid (H4btc), and mixed with three isomeric dipyridyl ligands, three novel 3D Cu(II) coordination polymers [Cu2(btc)(4,4′-bpt)]·2H2O (1) [4,4′-bpt = 1H-3,5-bis(4-pyridyl)-1,2,4-triazole], [Cu(btc)0.5(3,4′-bpt)]·0.5H2O (2) [3,4′-bpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4- triazole] and [Cu(btc)0.5(3,3′-bpt)]·2H2O (3) [3,3′-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole] have been synthesized and characterized, respectively. 1 is a 3D pillared double-layer complex containing a novel bilayer unit; 2 is a 3D pillared-layer architecture with (4,4)-sql layer; 3 exhibits a 3D structure containing 3D [Cu(btc)]∞ motif and 1D [Cu(bpt)]∞ chain. The topological analysis shows that 1 can be simplified to a (4,6)-connected network with the Schläfli symbol of (42·64)2(48·67), 2 a (4,6)-connected network with the symbol of (44·62)(44·610·8), and 3 a four-connected topology with the symbol of (32·103·11)2(32·104).