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Four new zinc(II) complexes based on the same ligand, {Zn(ptp)(H2O)]2 (1), [Zn(ptp)(CH3OH)]n (2), [Zn(ptp)]n (3), and {[Zn3(ptp)3](DMF)2(H2O)}n (4) [H2ptp = 2,3-bis(pyridine-2-yl)-5,6-di-1H-tetrazol-5-ylpyrazine], have been synthesized by solvothermal methods. All of the complexes have been structurally characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analyses show that complex 1 possesses a centrosymmetrical neutral dinuclear structure and 2 has 1D right-handed helical chains, with the 21 axis expanding along the crystallographic b direction; 3 features a 2D chiral-layered structure with (6,3) net, and complex 4 displays a 3D porous framework with (4,122) topology. The various architectures (0D, 1D, 2D, and 3D) of these four complexes indicated that reaction conditions (temperature and solvent) play an important role in the formation of such coordination structures; namely, various structures can be obtained from the same reactants by controlling and changing the reaction conditions in this system. The luminescent properties of all of the complexes and the corresponding ligand have been investigated in the solid state at room temperature. Moreover, adsorption properties (N2, H2, O2, CO2, and CH4) of the 4a (desolvated 4) have been studied, and the results show that 4a possesses a moderate capability of gas sorption for N2, H2, O2, and CO2 gases, with high selectivity ratios for O2 over H2 at 77 K and CO2 over CH4 at 273 K. [ABSTRACT FROM AUTHOR]

Two cobalt(II) coordination polymers [Co(H2O)2(H2btec) (bpp)2]n (1) and {[Co2(H2O)4(bpp)3(btec)]· 4H2O}n (2) were synthesized under ambient conditions with 1,2,4,5-benzenetetracarboxylic acid (btec) and 1,3-bi(4-pyridyl)propane (bpp) as mixed ligands. Complex 1 is characteristic of one-dimensional chains bridged by H2btec ligands, the terminal bpp ligands complete the coordination sphere of the cobalt atoms and are further hydrogen-bonded to neighboring chains via O-H· · · N bonds. Complex 2 features a three-dimensional framework constructed by btec4- and co-bridging bpp ligands. The cobalt ions in 2 are joined together by the btec ligands to generate Co4 squares which link to each other in an corner-sharing mode to form a 3D topology. The terminal bpp ligands filling in the networks further contribute to the stability of the crystal structure. [ABSTRACT FROM AUTHOR]

The influence of the nature of metal ions and reaction conditions on the formation of group IIB metal coordination architectures of a tetrazole ligand, 2-(1H-tetrazol-5-yl)pyrazine (HL), and the luminescent properties of some complexes have been investigated. At room temperature, the reactions of Zn(NO3)2∙6H2O (or ZnCl2) and Cd(NO3)2∙6H2O with HL gave rise to two reported complexes, [M(L)2(H2O)2] (1 and 2, Acta Crystallogr., Sect. C, 2006, 62, m614; Acta Crystallogr., Sect. E, 2006, 62, m2841), respectively. However, under hydrothermal conditions, the same reactions yield 1 and another complex, {[Cd2(L)4](H2O)0.25}n (3), respectively. In both preparation conditions mentioned above, the HL ligand reacts with Hg(OAc)2 (or HgBr2) to give complexes, [Hg(L)2]n (4), [Hg(L)2]n (5) and [Hg(L)Br]n (6) with different structures. 1 and 2 have a similar mononuclear structure and in the crystal structure such molecules are further assembled together to form a 3-D α-Pt topological framework with O–H⋯N hydrogen bonds. 4 possesses a 1-D chain structure, in which the Cd(ii) center is six-coordinated, with all coordination sites being occupied by N atoms of the ligands. Furthermore, such chains are interlinked viaπ⋯π interactions to form a 3-D framework. 4 has a 2-D (6,3) topological structure, in which the Hg(ii) center is six-coordinated to six N atoms of L, and the L ligand takes a chelating-bridging mode similar to that in 3. 5 has a 2-D (4,4) topological layer structure with the metal center being six-coordinated, and the six coordination sites are held by N atoms from four L ligands, taking different coordination modes. Moreover, such planes are generated to form a 3-D structure via two kinds of π⋯π interactions. 6 is a 2-D layer with the Hg(ii) coordinating to a Br atom and three N atoms of three tetrazole rings from different L ligands. This result shows that the metal ions and reaction conditions have significant influence on the group IIB metal complexes of this multifunctional ligand, and the intramolecular/intermolecular weak interactions are likely to play important roles in the formation of such complexes, especially linking the discrete subunits or low-dimensional entities into high-dimensional frameworks. In addition, the luminescent studies of HL and 1, 2, 3 and 6 indicate that they display blue emissions with different densities in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

The title complex, [HgBr2(C19H24S2)] n, has a single-chain structure in which adjacent HgBr2 units are linked by bridging ligands. The HgII centre has a distorted tetra­hedral coordination environment formed by two Br− anions and two S atoms from distinct ligands. [ABSTRACT FROM AUTHOR]

Exploring the relationship between the geometrical structures and spectral properties has great significance to design some desirable materials. For important pyrrole contained macromolecules, there is a new complex of Zn tetrapyrrin with opened chain ligand derived from breaking one methine bridged of Zn porphyrin. The frontier molecular orbitals, absorption and emission properties of such Zn tetrapyrrin complexes are investigated by density functional theory (DFT) and its time-dependent density functional theory (TD-DFT) methods. Compared to Zn porphyrin, the HOMOs and LUMOs are no longer degenerate, the lowest lying absorption and emission of Zn tetrapyrrin start to increase in intensity with the shifting of charge transfer transition band to near-infrared region. We hope these theoretical studies will assist the design of novel molecular materials. [ABSTRACT FROM AUTHOR]

In the structure of the title compound, [Ni2(N3)4(C5H5N)4]n, neutral chains of NiII atoms are bridged alternately by double end-on and double end-to-end azide bridges. Each NiII center is located on a crystallographic general position and in a slightly distorted octahedral coordination environment with two pyridine ligands in the trans positions. Both end-on and end-to-end double azide bridges become equivalent because of the inversion centers lying between each pair of adjacent NiII atoms. In the chain, the Ni⋯Ni separations across the end-on and end-to-end azide bridges are 3.236 (4) and 4.975 (4) Å, respectively, and the end-on azide bridging NiNNi angle is 100.8 (2)°. [ABSTRACT FROM AUTHOR]

The self-assembly reactions of Ln(NO 3) 3·aq (Ln = La, Nd, Sm, Gd, Dy, Er, and Yb) with K 3[Fe(CN) 6] and three monosulfoxide ligands, dimethylsulfoxide (DMSO), diethylsulfoxide (DESO), and tetramethylene sulfoxide (TMSO), respectively, in water give rise to three series of 21 Ln III−Fe IIIcomplexes with ten kinds of compositions and structures: cis-[Fe(CN) 4(μ-CN) 2La(H 2O) 3(DMSO) 3] n· nH 2O ( 1), [Fe(CN) 5(μ-CN)Ln(H 2O) 3(DMSO) 4]·H 2O [Ln = Nd ( 2), Dy ( 5)], [Fe(CN) 5(μ-CN)Ln(H 2O) 4(DMSO) 3]·H 2O [Ln = Sm ( 3), Gd ( 4)], trans-[Fe(CN) 4(μ-CN) 2Ln(H 2O)(DMSO) 4] n[Ln = Er ( 6), Yb ( 7)], [Fe(CN) 6][La(H 2O) 6(DESO) 3] ( 8), trans-[Fe(CN) 4(μ-CN) 2Ln(H 2O) 4(DESO) 2] n·2 nH 2O [Ln = Nd ( 9), Sm ( 10), Gd ( 11), Dy ( 12), Er ( 13)], cis-[Fe(CN) 4(μ-CN) 2Yb(H 2O) 3(DESO) 2] n·2 nH 2O ( 14), [Fe(CN) 5(μ-CN)Ln(H 2O) 3(TMSO) 4]·1.5H 2O [Ln = La ( 15), Nd ( 16), Gd ( 18)], cis-[Fe(CN) 4(μ-CN) 2Sm(H 2O) 4(TMSO) 2] n( 17) and cis-[Fe(CN) 4(μ-CN) 2Ln(H 2O) 3(TMSO) 2] n· nH 2O [Ln = Dy ( 19), Er ( 20), Yb ( 21)]. The X-ray structure analyses show that 2− 5, 15, 16, and 18have cyano-bridged dinuclear structures; 1, 6, 7, 9− 14, 17, and 19− 21form one-dimensional (1D) chain structures; but 8is an ionic compound without cyano-bridging. For those complexes with 1D structure, there are also different configurations ascribed to the cis- or trans-coordination of bridging CN −moieties to the Fe IIIion. The coordination of two CN −moieties to one Ln IIIion is all- trans(N−Ln−N > 90°), mainly due to the steric effect of Fe(CN) 63−entities. Further, such complexes feature extensive O−H···O and O−H···N hydrogen bonds that give rise to different three-dimensional (3D) supramolecular structures and stabilize and influence these structures. The differences of composition and structure of these complexes may be attributed to the structural differences of the three monosulfoxide blocking ligands, as well as different lanthanide ions to some extent, although a general rule (or underlying relationship) can not be deduced. [ABSTRACT FROM AUTHOR]