Search

A three-dimensional porous metal-organic framework (MOF), UTSA-86, made up of cadmium ions and a chromophoric tetraphenylethene-based tetracarboxylate ligand, 4′,4′′′,4′′′′′,4′′′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis(1,1′-biphenyl-4-carboxylic acid (H4ettc), has been synthesized and characterized by single-crystal X-ray diffraction analysis. This multifunctional MOF exhibits permanent porosity, selective gas uptake, and luminescence sensing of metal ions. [ABSTRACT FROM AUTHOR]

By assembling CoII ions and a combination of 5-(4-pyridyl)tetrazole (4-ptz) and formate ions, two distinct metal-organic frameworks, [Co3(4-ptz)5(HCOO)(H2O)2] and [Co3(4-ptz)4(dmf)2(HCOO)2 ] (dmf= N, N′-dimethylformamide), were synthesized. They were both characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. Structural analyses revealed that by slightly modulating the coordination environment of the trinuclear cobalt cluster, two complexes were formed featuring unusual six-connected nets reminiscent of a pyrazole-type linear trinuclear cobalt cluster as compared with the classic eight-connected bcu topology. In addition, [Co3(4-ptz)5(HCOO)(H2O)2] interacted strongly with CO2, with an adsorption enthalpy of 29.2 kJ mol−1, and in a selectivity study, the uptake ratios of CO2/N2 (from a 15:85 mixture) and CO2/CH4 (50:50 mixture) were 77.6 and 37.7, respectively. Magnetic studies on both complexes revealed weak antiferromagnetic coupling between the CoII ions. [ABSTRACT FROM AUTHOR]

Two series of lanthanide metal-organic frameworks, [KLn3(FDCA)5(H2O)5] ·solvent ( 1Ln) (Ln = La 1, Ce 2, Pr 3), [K4Ln8(FDCA)14(H2O)30] ·2(H2FDCA) ·DMAC ·10(H2O) ( 2Ln) (Ln = Eu 4, Gd 5, Tb 6, Dy 7, Er 8, DMAC = N, N-dimethylacetamide), have been prepared by solvothermal reactions of 2,5-furandicarboxylic acid (H2FDCA) and KNO3 with the corresponding lanthanide nitrate. X-ray crystal structure analyses show that 1Ln possesses a 3D network based on the '16-crown-6-like' secondary building unit (SBU), whereas 2Ln exhibits a 1D framework with a '23-crown-9-like' SBU. The structural investigation unambiguously demonstrated that the lanthanide contraction affects the formation of 1Ln and 2Ln. Meanwhile, the solid-state photoluminescent properties of 4 and 6 were also investigated at room temperature and the luminescence intensity of 4 is sensitive to small molecules. [ABSTRACT FROM AUTHOR]

Abstract: In our efforts to investigate the influence of the backbone of different triazole-based bridging ligands on the structure of their metal complexes, four new coordination polymers, {[Cu(L1 )2(H2O)2]Cl2} n (1), [Cu(L2 )2Cl2] n (2), [Co(L2 )2(SCN)2] n (3), and [Cu(L3 )2(NO3)2] n (4), (L1  = 1,2-bis(triazol-1-ylmethyl)benzene, L2  = 1,3-bis(triazol-1-ylmethyl)benzene, L3  = 1,4-bis(triazol-1-ylmethyl)benzene), have been synthesized. All the complexes have been structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Structural analyses show that 1 and 4 possess 2D coordination networks with (4,4) topology, and 1 shows a diagonal–diagonal inclined interpenetration. 2 and 3 are isostructural and feature 1D double chain, which further connected by C–H···Cl or π···π weak interactions to form 2D supramolecular frameworks. The results show that the structures of ligands (with different non-coordination backbone spacers) play important roles in the formation of such coordination architectures. Furthermore, EPR (Electron Paramagnetic Resonance) spectra of CuII complexes (1, 2, and 4) have been investigated in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Two new metal-organic frameworks, {[CuLI]·CHCl3}∞(1) and {[HgL(Br)2]4·2CH2Cl2}∞ (2) have been prepared by reacting CuI and HgBr2 with the new flexible ligand L [L = 2,3-Bis(benzimidazol-1-ylmethyl)quinoxaline]. Both complexes have been characterized by elemental analysis, IR, TGA, XRPD, and single crystal X-ray diffraction determination. In 1, the Cu(I) ion takes tetrahedral coordination geometry, and the flexible ligands bridge dinuclear units (Cu2I2) to form a one dimensional (1D) double chain structure. While in 2, the Hg(II) coordinates to two bromine ions and two nitrogen donors of L to form a 1D coordination polymer. The structure differences of the two complexes mainly depend on the geometry of the metal ions and the influence of anions. The coordination features of the ligand have also been primarily investigated by density functional theory (DFT) calculations. In addition, the fluorescent properties of the complexes and free ligand L have been investigated in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Four Ag(I) coordination complexes formulated as {[Ag(L1 )(ClO4)]}n (1), {[Ag(L1 )(NO3)]}n (2), {[Ag(L1 )(PF6)]}2 (3) and {[Ag(L2 )](ClO4)·CH3OH}n (4), (L1 = 3,6-bis(1-pyrazolyl)pyridazine, L2 = 3,6-bis(3,5-dimethyl-1-pyrazolyl)pyridazine) have been synthesized in the presence of different anions [ClO4 − (1) and (4), NO3 − (2), PF6 − (3)] and structurally characterized by FT-IR spectra, elemental analysis and X-ray diffraction. Studies of X-ray diffraction reveal that complexes 1, 2 and 4 show infinite helical chains, which are the alternate left- and right-handed helical chains. Furthermore, helical chains are arranged to 2D sheet via C–H⋯O (from anion O atoms) hydrogen bonds. As the anion changed to PF6 −, a dinuclear molecule is formed in complex 3, further constructing a 2D sheets by C–H⋯F hydrogen bonds. The photoluminescence properties of all the complexes 1–4 have been investigated in the solid state at room temperature. [Copyright &y& Elsevier]

Abstract: Two new 3-D supramolecular networks, {[Cd2(dap)2(tp)2(H2O)2]·2H2O} n (1) and {[Cu3(tp)2(dpq)2(OH)2]} n (2) (tp, terephthalate; dap, 5,6-diamino-1,10-phenanthroline; dpq, dipyrido[3,2-d:2′,3′-f]quinoxaline), have been synthesized and structurally characterized by X-ray diffraction. Single-crystal X-ray analyses show that complex 1 is constructed by CdII and mixed ligands of daps and tps to form a 1-D polymer chain. In complex 2, a tetra-coordinated CuII and two penta-coordinated CuII are linked by two bridging hydroxyl oxygen atoms to form a Cu3(OH)2(dpq)2 unit, which is a noteworthy feature in the framework, and such units are connected through tp to form a 2-D lamellar polymer. Moreover, complexes 1 and 2 are further extended into 3-D supramolecular networks by H-bonding and π–π stacking interactions, respectively. [Copyright &y& Elsevier]

Abstract: To explore the influence for the dimensionalities of coordination polymers, in presence of different anions with different behaviors, three new coordination polymers with different dimensionalities have been prepared by reacting M2+ (M=Zn or Co) with two structurally related rod-like poly(imidazole) ligands, 1,4-bis(benzoimidazol-1-yl)-phenyl (L1 ) and 1,4-bis(imidazol-1-yl)-phenyl (L2 ). Such three new coordination polymers with different architectures, [Zn(L1 )(NO3)2] n (1), {[Zn(L2 )2]·2BF4·2HCCl3·2H2O} n (2) and [Co(L2 )(SO4)] n (3), have been determined by single-crystal X-ray diffraction analysis and characterized by elemental analysis, and IR analysis. Complex 1 is alternative linked by octahedral Zn centers and the ligand L1 to exhibit a one-dimensional (1D) chain structure. However, complexes 2 and 3 both present layered structures contain a similar -L(ligand)–M(metal)-L–M- chain motifs that found in complex 1. In complex 2, each Zn(II) ion is coordinated by four different L2 to form a undulated sheet. Complex 3 also present a undulated sheet structure, however, they were connected by the group and the L2 ligands, different from only of the L2 ligands in complex 2. The result indicates that the different anions behaviors could be the great influence on the degree of dimensionality of coordination polymers. [Copyright &y& Elsevier]

Abstract: Three new CdII complexes with two analogous ligands of 2,2′-biimidazole (H2biim) and 2,2′-bibenzimidazole (H2bbim), have been synthesized and characterized by elemental analyses, IR spectroscopy as well as single crystal X-ray diffraction. The results reveal that the structures of the complexes range from one-dimensional (1D) chains in [Cd(H2biim)(N3)2] n (1) to two-dimensional (2D) layer in [Cd(bbim)0.5(Hbbim)] n (2) and three-dimensional (3D) network in [Cd3(biim)2(Hbiim)(N3)] n (3), with various modes of these ligands, which is tuned by different polarity of solvents and pH values. The fluorescent spectra of these complexes and ligands have been also investigated in the solid state at room temperature. [Copyright &y& Elsevier]