Structural Diversities and Fluorescent and Photocatalytic Properties of a Series of Cu^II Coordination Polymers Constructed from Flexible Bis-pyridyl-bis-amide Ligands with Different Spacer Lengths and Different Aromatic Carboxylates

Thirteen new Cu^II coordination polymers, namely, [Cu­(3-dppa)­(1,3,5-HBTC)] (1), [Cu­(3-dpha)­(1,3,5-HBTC)­(H₂O)]­·H₂O (2), [Cu₃(3-dpsea)­(1,3,5-BTC)₂­(H₂O)₅]·4H₂O (3), [Cu­(3-dpba)­(1,2-BDC)]­·H₂O (4), [Cu­(3-dpha)­(1,2-BDC)] (5), [Cu­(3-dpsea)­(1,2-BDC)]­·H₂O (6), [Cu₂(3-dpyp)­(1,3-BDC)₂­(H₂O)₄]­·3H₂O (7), [Cu­(3-dppa)­(1,3-BDC)­(H₂O)]­·2H₂O (8), [Cu­(3-dppia)­(1,3-BDC)­(H₂O)₂]­·2H₂O (9), [Cu₂(3-dpsea)₂­(1,3-BDC)₂­(H₂O)₂]­·7H₂O (10), [Cu­(3-dpba)­(1,4-NDC)]­·3H₂O (11), [Cu­(3-dpyh)­(1,4-NDC)­(H₂O)]­·3H₂O (12), [Cu­(3-dpyh)_0.5­(1,4-NDC)]­·H₂O (13), have been purposefully synthesized under hydrothermal conditions [3-dppa = N,N′-di­(3-pyridyl)­propanediamide, 3-dpba = N,N′-di­(3-pyridyl)­butanediamide, 3-dpha = N,N′-di­(3-pyridyl)­hexanedioicdiamide, 3-dppia = N,N′-di­(3-pyridyl)­pimelicdiamide, 3-dpsea = N,N′-di­(3-pyridyl)­sebacicdiamide, 3-dpyp = N,N′-di­(3-pyridine­carboxamide)-1,3-propane, 3-dpyh = N,N′-di­(3-pyridine­carboxamide)-1,6-hexane, 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H₂BDC = 1,2-benzenedicarboxylic acid, 1,3-H₂BDC = 1,3-benzenedicarboxylic acid and 1,4-H₂NDC = 1,4-naphthalenedicarboxylic acid]. Complexes 1–3 based on the same auxiliary ligand show various structures. Complex 1 features a one-dimensional (1D) ∞-like double-chain structure, which consists of a [Cu-1,3,5-HBTC]_n chain and [Cu-3-dppa]_n meso-helical chain. Complex 2 possesses a (2,4) undulated honeycomb (hcb) net. Complex 3 is a 3-fold interpenetrating three-dimensional (3D) framework, which shows trinodal (2,3,3)-connected topology with the Schläfli symbol of (10·12²)₂(10³)₂(12). Complexes 4–6 with 1,2-BDC as secondary ligand exhibit different two-dimensional (2D) layer structures. Complex 4 exhibits a 2D (2,4)-connected (4·12⁴·14)­(4) net. Complexes 5 and 6 have similar structures and show 2D networks with undulated sql topology. For complexes 7–10 based on 1,3-BDC secondary ligand, complex 7 shows a 1D zigzag chain, while complexes 8–10 have similar wave-like 2D structures. When 1,4-NDC was used as the auxiliary ligand, complex 11 is a 2D puckered (4,4) network, complex 12 reveals a 4-connected topology with the point symbol of (4⁴·6²), while complex 13 exhibits a 3-fold interpenetrating 3D α-Po framework. The structural diversity indicates that the bis-pyridyl-bis-amide ligands with different spacers and the aromatic polycarboxylates play important roles in tuning the dimensionalities and structures of the title complexes. The fluorescent and photocatalytic properties for 1–13 have also been investigated in detail.