- Temperature, cooling rate, and additive-controlled supramolecular isomerism in four Pb(II) coordination polymers with an in situ ligand transformation reaction
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Solvothermal reactions of Pb(Ac)2 with a new flexible 1,3-bis(4-pyridyl-3-cyano)propane (1, BPCP) ligand under different synthesis conditions via an in situ ligand transformation reaction produced three true coordination polymorphs, namely, [PbL2-]n (for 2 and 3) and [Pb3L2-3]n (4), as well as their polymorphic framework [(Pb2L2-)·2H 2O]n (5) (H2L = 1,3-bis(4-pyridyl-3-carboxyl) propane). These compounds were characterized by elemental analysis, IR, TG, PXRD, and single-crystal X-ray diffraction. In these compounds, the L 2-ligand exhibits different coordination conformations and modes tuned by different synthesis conditions, including reaction temperature, cooling rate, and additive, and constructs various architectures by bridging a variety of building units. Polymorphs 2 and 3 display a 3D framework with 1D channels built up from dinuclear ringlike [Pb2L2-2] units and dinuclear semi-ring-like [Pb2L2-] units, respectively. Polymorph 4 also features a 3D architecture constructed from dinuclear ringlike [Pb2L2-2] units interlinked by the L2- ligand. Interestingly, the framework of 4 is big enough to allow the other net to penetrate to form a 2-fold interpenetrating framework with a trinodal (3,6,10)-connected topology with a point symbol of (4 3)(44·610·8)(4 8·624·89·104). For 5, there exists two kinds of dinuclear ringlike [Pb2L 2-2] units. These [Pb2L2- 2] units are interconnected by Pb atoms to afford a 2D undulant network that is further connected by the hydrogen-bonding interactions and weak interactions to afford a 3D supramolecular network. In addition, the photoluminescence properties of 1-5 and the H2L ligand in the solid state at room temperature were also investigated.
- Deng, Dongsheng,Liu, Leilei,Ji, Bao-Ming,Yin, Guojie,Du, Chenxia
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- New flexible bis-pyridyltetrazole ligands for use in coordination polymer formation: Synthesis and structural studies
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In this work, we have further developed the pyridyl-tetrazole ligand systems into bis-tetrazole systems, where the linker introduced to join these moieties was a flexible (CH2)3 backbone, with the intention of forming frameworks with potential voids. We synthesised three different pyridyl-tetrazoles linked via this flexible backbone through the pyridine ring and not the tetrazole rings. Two crystals of ligand 1 were solved by X-ray crystallography and showed interesting polymorphism. No crystals of the copper(II) complexes of the ligands could be obtained, suggesting that they were polymeric in nature.
- Sheridan, Ursula,Gallagher, John F.,McGinley, John
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- Controlled crystallization of mixed-ligand complexes of 1,3-bis(4-pyridyl)propane-N,N′-dioxide with metal(II) thiocyanates: Isostructurality in coordination networks bearing different mono- and di-nuclear nodes
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The new flexible spacer ligand 1,3-bis(4-pyridyl)propane-N, N′-dioxide forms three classes of isomorphous compounds with metal(II) thiocyanates at controlled ligand-metal molar ratios, and its μ 3-O,O,O′ mode leads to a pair of coordination networks having the same (4, 4) topological characteristics but different mono- and di-nuclear nodes.
- Zhang, Lin-Ping,Lu, Wen-Jie,Mak, Thomas C. W.
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p. 2830 - 2831
(2007/10/03)
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