Static Retention of Dynamic Chiral Arrangements for Achiral Shear Thinning Metal-Organic Colloids.

Chiral compounds are known to be important not only because they are the fundamental components of living organisms, but also for their unique chiroptical properties. In recent years, scientists have fabricated several chiral organic supramolecular aggregates by using chiral physical fields, such as vortex flow. Herein, the relationship between dynamic chiroptical properties and rheological nature is discussed, suggesting the shear thinning properties of non-Newtonian fluids might help colloidal particles adopt a chiral arrangement in vortices. Furthermore, the storage modulus of colloids could be increased by adding a linking agent, which successfully kept the dynamic chiroptical properties in the static state. Moreover, the salt effect on the host-guest interaction involved in the colloids was studied, the results suggested a significant enhancement of the transferred dynamic circular dichroism for the achiral guest molecule.

Encapsulating Naphthalene in an Electron-Deficient MOF to Enhance Fluorescence for Organic Amines Sensing.

Host-guest encapsulation of electron-rich naphthalene molecules into a weakly emissive porous metal-organic framework based on π-electron-deficient (π-acidic) naphthalene diimide tectons leads to orange-emissive crystals, which can be used to sense strongly basic organic amines in a fast response, high photostability, and tunable sensitivity. Moreover, such host-guest inclusion crystals are also a good photochromic probe for the detection of weakly basic N-methyl-2-pyrrolidone and N,N-dimethylformamide molecules.

Enantioselective synthesis of a chiral coordination polymer with circularly polarized visible laser.

Circular dichroism is known to be the feature of a chiral agent which has inspired scientist to study the interesting phenomena of circularly polarized light (CPL) modulated molecular chirality. Although several organic molecules or assemblies have been found to be CPL-responsive, the influence of CPL on the assembly of chiral coordination compounds remains unknown. Herein, a chiral coordination polymer, which is constructed from achiral agents, was used to study the CPL-induced enantioselective synthesis. By irradiation with either left-handed or right-handed CPL during the reaction and crystallization, enantiomeric excesses of the crystalline product were obtained. Left-handed CPL resulted in crystals with a left-handed helical structure, and right-handed CPL led to crystals with a right-handed helical structure. It is exciting that the absolute asymmetric synthesis of a chiral coordination polymer could be enantioselective when using CPL, and provides a strategy for the control of the chirality of chiral coordination polymers.

Di-µ2-chlorido-dichloridobis(dimethylformamide)tetrakis[µ3-1-(2-oxidobenzoyl)-2-(2-oxo-2-phenylethanethioyl)hydrazine-1,2-diido]octacopper(II) dimethylformamide disolvate.

The title compound, [Cu8(C15H10N3O3S)4Cl4(C3H7NO)2]·2C3H7NO, consisting of eight Cu(II) cations, four trianionic 1-(2-oxidobenzoyl)-2-(2-oxo-2-phenylethanethioyl)hydrazine-1,2-diide ligands, four chloride ligands and two coordinated and two solvent dimethylformamide molecules, crystallizes with the octanuclear molecule located on an inversion centre. The two halves of the molecule are connected by two bridging Cl atoms. This is the first example of an octanuclear complex based on a thiosemicarbazone-derived ligand.

trans-Diaqua-bis-[5-(pyridine-3-carboxamido)-tetra-zolido-κ(2)O,N(1)]zinc dihydrate.

The title compound, [Zn(C(7)H(5)N(6)O)(2)(H(2)O)(2)]·2H(2)O, consists of one Zn(II) ion located on the crystallographic inversion centre, two 5-(pyridine-3-carboxamido)-tetra-zolide ligands, two coordinated water mol-ecules and two free water mol-ecules. The Zn(II) ion adopts a slightly distorted octa-hedral coordination geometry formed by the N,O-chelating ligands and two O water atoms. The pyridine N atoms are not coordinated. In the crystal, complex mol-ecules are connected by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, forming a three-dimensional network.

Poly[µ3-hydroxido-µ6-sulfato-µ3-(1,2,4-triazolato-κ3N1:N2:N4)-dicadmium(II)]: a cadmium-triazolate coordination polymer with a pseudo-cubane-like tetranuclear cluster.

The title complex, [Cd(2)(C(2)H(2)N(3))(OH)(SO(4))](n), is a three-dimensional metal-organic framework consisting of pseudo-cubane-like tetranuclear cadmium clusters, which are formed by four Cd(II) atoms, two sulfate groups and two hydroxide groups. The tetranuclear cadmium clusters are connected into a layered substructure by Cd-O bonds and adjacent layers are linked by triazolate ligands into a three-dimensional network. A photoluminescent study revealed that the complex exhibits a strong emission in the visible region which probably originates from a π-π* transition.

catena-Poly[[bis(µ-2-sulfonatobenzoato)bis[triaquagadolinium(III)]]-µ-oxalato].

The asymmetric unit of the title coordination polymer, [Gd(2)(C(7)H(4)O(5)S)(2)(C(2)O(4))(H(2)O)(6)](n) or [Gd(2-SB)(ox)(0.5)(H(2)O)(3)](2n) (2-SB is 2-sulfonatobenzoate and ox is oxalate), (I), consists of one Gd(III) ion, one 2-SB anion, three coordinated water molecules and one half of an ox ligand. The ox ligand is located on a crystallographic inversion centre. The Gd(III) centre shows a distorted tricapped trigonal-prismatic coordination formed by nine O atoms from two 2-SB anions, one ox ligand and three coordinated water molecules. The carboxylate and sulfonate groups of the 2-SB anions adopt µ(2)-η(1):η(2) and µ(1)-η(0):η(0):η(1) coordination modes to link two Gd(III) ions, generating a centrosymmetric binuclear [Gd(2)(2-SB)(2)(H(2)O)(6)](2-) subunit. The ox ligand acts as a bridge, linking the binuclear [Gd(2)(2-SB)(2)(H(2)O)(6)](2-) subunits into a one-dimensional chain structure parallel to the b axis. Furthermore, extensive O-H···O hydrogen bonds connect the chains into a three-dimensional supramolecular architecture.

Poly[bis(mu-4-benzoyl-1-isonicotinoylthiosemicarbazide-kappa2N:S)dichloridocadmium(II)].

The asymmetric unit of the title complex, [CdCl(2)(C(14)H(12)N(4)O(2)S)(2)](n), consists of one Cd(II) ion located on the crystallographic inversion centre, one 4-benzoyl-1-isonicotinoylthiosemicarbazide ligand and one chloride ligand. The central Cd(II) ion adopts a distorted octahedral coordination geometry formed by two pyridyl N atoms of two ligands, two S atoms of two other ligands and two chloride ligands. The thiosemicarbazide ligands act as bridges, linking the metal ions into a two-dimensional layered structure parallel to the bc plane. Intermolecular N-H...O hydrogen bonds and C-H...pi interactions exist between adjacent layers.

Solvent-assisted planar structure of a stilbene-based salicylhydrazone compound: crystal structure, solvent- and aggregation-induced emission, and switchable luminescence colouration.

A novel stilbene-based salicylhydrazone compound {systematic name: (E)-4,4'-(ethene-1,2-diyl)bis[(N'E)-N'-(2-hydroxybenzylidene)benzohydrazide] dimethyl sulfoxide disolvate, C30H24N4O4·2C2H6OS or L·2DMSO} was synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction and luminescence spectroscopy. The title compound crystallizes in the monoclinic space group P21/c, with half a symmetry-independent L molecule and one dimethyl sulfoxide (DMSO) solvent molecule in the asymmetric unit. The L molecule adopts an almost planar structure, with a small dihedral angle between the planes of the stilbene and salicylhydrazone groups. There are multiple π-π stacking interactions between adjacent L molecules. The DMSO solvent molecules act as proton donors and acceptors, forming hydrogen bonds of various strengths with the L molecules. In addition, the geometry optimization of a single molecule of L and its luminescence properties either in solution, as a solvated solid or as a desolvated solid were studied. The compound shows an aggregation-induced emission (AIE) effect and exhibits switchable luminescence colouration in the solid state by the simple removal or re-addition of the DMSO solvent.

Diaqua-bis(2,2'-biimidazole)cobalt(II) 4,4'-dicarboxy-biphenyl-3,3'-di-car-boxylate.

In the title compound, [Co(C(6)H(6)N(4))(2)(H(2)O)(2)](C(16)H(8)O(8)), the Co(II) cation and the organic anion occupy different crystallographic inversion centres and, as a consequence, the asymmetric unit comprises two half-mol-ecules. The benzene groups are coplanar. The four coordinating N atoms of the two bidentate biimidazole ligands define the equatorial plane of a slightly distorted octa-hedral CoO(2)N(4) geometry, and the water O atoms lie in the axial coordination sites. Translational (a,) and inversion-related symmetry operations link the Co complex mol-ecules and the negatively charged carboxyl-ate anions via inter-molecular N-H⋯O and O-H⋯O hydrogen bonds into sheets parallel to (01). The coordinated water mol-ecules connect the sheets through O-H⋯O hydrogen bonds, forming a three-dimensional framework. In addition, two intra-molecular O-H⋯O hydrogen bonds are observed between the carboxyl and carboxyl-ate groups.

Diaqua-bis(2,2'-biimidazole)zinc(II) 4,4'-di-carboxybiphenyl-3,3'-di-carboxyl-ate.

In the title compound, [Zn(C(6)H(6)N(4))(2)(H(2)O)(2)](C(16)H(8)O(8)), the Zn(II) atom, located on an inversion centre, is coordinated by two aqua and two bidentate biimidizole ligands, resulting in a slightly distorted octa-hedral ZnO(2)N(4) geometry. The four N atoms from the two biimidizole ligands lie in the equatorial plane and the two aqua O atoms lie in the axial sites. The biphenyl-tetra-carboxyl-ate anion also lies on an inversion centre. The Zn(II) complex cation and the anion are held together by N-H⋯O hydrogen bonds, forming a zigzag chain along [21]. The chains are further connected by water mol-ecules via O-H⋯O hydrogen bonds.

Four isostructural lanthanide(III) coordination compounds based on a new N-oxydic pyridyl naphthalenediimide ligand: synthesis and characterization.

Naphthalenediimides, an attractive class of electron-deficient organic dyes with rich redox and photoredox properties, have been investigated extensively as building blocks for coordination networks or metal-organic frameworks in recent decades. However, most of the available work has focused on d-block metal cations rather than f-block lanthanide ions, whose complexes exhibit a large variability in coordination numbers. In this article, four coordination polymers composed of naphthalenediimides and lanthanide cations, namely catena-poly[[[tris(nitrato-κ2O,O')lanthanide]-bis{µ-N,N'-bis[(1-oxidopyridin-1-ium-3-yl)methyl]-1,8:4,5-naphthalenetetracarboxdiimide-κ2O:O'}-[tris(nitrato-κ2O,O')lanthanide]-µ-N,N'-bis[(1-oxidopyridin-1-ium-3-yl)methyl]-1,8:4,5-naphthalenetetracarboxdiimide-κ2O:O'] methanol disolvate], {[Ln(C26H16N4O4)1.5(NO3)3]·CH3OH}n, with Ln = Eu, 1, Gd, 2, Dy, 3, and Er, 4, have been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analyses revealed that the four compounds are isomorphic and that each asymmetric unit contains one nine-coordinated Ln centre, one and a half diimide ligands, three nitrate anions and one uncoordinated methanol molecule. In addition, each metal centre is surrounded by nine O atoms in a distorted tricapped trigonal-prismatic geometry. Two centres are bridged by two cis ligands to form a ring, which is further bridged by trans ligands to generate one-dimensional chains. Neighbouring chains are stacked via π-π interactions between pyridine rings to give a two-dimensional structure, which is stabilized by π-π interactions between naphthalene rings, forming the final three-dimensional supermolecular network. Solid-state optical diffuse-reflectance spectral studies indicate that compound 4 is a potential wide band gap semiconductor.

Mu2-acetato-kappa(2)O:O'-tris(mu2-ferrocenecarboxylato-kappa(2)O:O')bis[(N,N-dimethylformamide-kappaO)copper(II)].

The title compound, [Cu(2)Fe(3)(C(5)H(5))(3)(C(2)H(3)O(2))(C(6)H(4)O(2))(3)(C(3)H(7)NO)(2)], belongs to the classic dimeric paddle-wheel structure type. It is an unusual example in that it contains two different carboxylate groups, viz. ferrocenecarboxylate and acetate. With three ferrocenecarboxylate groups and only one acetate group bridging the two Cu centres, a noncentrosymmetric molecular arrangement results.

Two novel donor-acceptor hybrid heterostructures with enhanced visible-light photocatalytic properties.

The ternary combination of metal cations, CuI and viologen based carboxylate leads to two donor-acceptor hybrid heterostructures with novel cuprous iodide clusters and narrow energy gaps. Thanks to the facilitated electron transfers between both donor and acceptor components, these unique hybrids exhibit enhanced photocatalytic degradation activities towards organic dyes under visible light irradiation in comparison with those of bulk CuI and viologen semiconductors.

A two-dimensional CdII coordination polymer based on naphthalenediimide: synthesis, crystal structure and photochromic properties.

Naphthalenediimides, a class of organic dyes with an expanded π-electron-deficient plane, have attracted considerable interest because of their photoinduced electron transfer from neutral organic moieties to stable anionic radicals. This makes them excellent candidates for organic linkers in the construction of photochromic coordination polymers. Such a photochromic two-dimensional coordination polymer has been prepared using N,N'-bis(pyridin-4-ylmethyl)naphthalene-1,8:4,5-bis(dicarboximide) (DPMNI). In crystallization tubes, upon slow diffusion of an MeOH solution of cadmium perchlorate into a CHCl3 solution of DPMNI, the complex poly[[bis[µ2-2,7-bis(pyridin-4-ylmethyl)benzo[imn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone-κ2N:N']bis(perchlorato-κO)cadmium(II)] chloroform tetrasolvate], {[Cd(C26H16N4O4)2(ClO4)2]·4CHCl3}n, (I), was obtained. The asymmetric unit contains one Cd2+ cation, two DPMNI ligands, two coordinated ClO4- anions and four CHCl3 solvent molecules. Each Cd2+ cation is interconnected by four DPMNI linkers to generate a neutral two-dimensional naphthalenediimide coordination network with all the ClO4- anions above or below this plane. Strong interlaminar anion-π interactions between the coordinated ClO4- anions and the imide rings of an adjacent layer lead to a three-dimensional supramolecular structure. Compound (I) exhibits reversible photochromic behaviour and photocontrolled tunable luminescence properties, which may originate from the photoinduced electron-transfer generation of radicals in the DPMNI ligand.

Synthesis and characterization of a photochromic magnesium(II) coordination polymer based on a naphthalene diimide ligand.

Naphthalene diimides, which are planar, chemically robust and redox-active, are an attractive class of electron-deficient dyes, which can undergo a single reversible one-electron reduction to form stable radical anions in the presence of electron donors upon irradiation. This makes them excellent candidates for organic linkers in the construction of photochromic coordination polymers. Such a photochromic one-dimensional linear coordination polymer has been prepared using N,N'-bis(3-carboxyphenyl)naphthalene-1,8:4,5-tetracarboximide (H2BBNDI). Crystallization of H2BBNDI with magnesium nitrate in an N,N'-dimethylformamide (DMF)/ethanol/H2O mixed-solvent system under solvothermal conditions afforded the one-dimensional coordination polymer catena-poly[[bis(dimethylformamide-κO)magnesium(II)]-bis[µ-N-(3-carboxylatophenyl)-N'-(3-carboxylphenyl)naphthalene-1,8:4,5-tetracarboximide-κ2O:O']], [Mg(C28H13N2O8)2(C3H7NO)2]n. The asymmetric unit contains half of a magnesium cation, one HBBNDI- ligand and one DMF molecule. Two partially deprotonated HBBNDI- ligands bridge two magnesium cations to form a one-dimensional chain. Strong inter-chain π-π interactions between the naphthalene rings of the HBBNDI- ligand and the imide rings of adjacent chains provide a two-dimensional structure. The supramolecular three-dimensional framework is stabilized by π-π interactions between naphthalene rings of neighbouring two-dimensional supramolecular networks. The complex exhibits a reversible photochromic behaviour, which may originate from the photoinduced electron-transfer generation of radicals in the HBBNDI- ligand.

Assembly of donor-acceptor hybrid heterostructures based on iodoplumbates and viologen coordination polymers.

The insertion of electron-rich iodoplumbate nanowires and nanolayers into layered electron-deficient metal-viologen frameworks leads to two donor-acceptor hybrid structures, respectively, which exhibit interesting semiconductor behaviors. Due to the bicontinuous donor and acceptor components, both of them exhibit highly efficient photocatalytic degradation activities over organic dyes under visible light irradiation compared to those of other iodoplumbate hybrid materials.

Construction of a bicontinuous donor-acceptor hybrid material at the molecular level by inserting inorganic nanowires into porous MOFs.

Herein, we report an unprecedented hybrid structure of electron-rich iodoplumbate nanowires precisely inserted into the periodic pores of electron-deficient pyridinium metal-organic frameworks (MOFs). To the best of our knowledge, this is the first example of semiconductive MOFs in situ loaded with inorganic semiconductive nanowires via a simple self-assembly method. Due to the dissimilar semiconductivities between the host and guest components, this hybrid also represents the first bicontinuous donor-acceptor hybrid at the molecular level based on host-guest interactions.

[Spectral study of two compounds of molybdate salt with beta-[Mo8O26] anion].

Two compounds of organic molybdate-alkali salt: [H(4,4'-bipy)]2[K2Mo8O26](I) and H3 [Na Mo8 O26] (4,4'-bipy)5 (H2O)4 (II), with beta-[Mo8O26]4- anion, were synthesized. The relationship between their properties and structures was studied by using FTIR, Raman, NIR-Vis and fluorescence etc. They possess isolating beta-[Mo8O26]4- anion, whose terminal O atoms combine with alkali. The FTIR and Raman spectra showed that the vibrational frequencies of the group are related to the structure of the materials. In UV-Vis spectra of compound (I) and (II), there is a characteristic wide peak at 280-300 nm. The fluorescence spectra of compound (I) and (II) were studied, which showed that the wide emission peak is from 450 to 650 nm and excited by 350 nm for compound (I), and the emission peak is from 400 to 550 nm and excited by 325 nm for compound (II). For compound (I), the intensity of emission becomes stronger with decreasing of temperature, and so does the fluorescence lifetime.

[Synthesis and spectral study of three polyoxovanadium clusters].

Three polyoxovanadium clusters, [{Ni(phen)}2 V4O12] x H2O I, [N(CH2CH2)3NH]Na(H2O)6 {K4 (H2O)4 [V10 O28]} (H2O)4 II and [(CH3)4N]6 [V15 O36 Cl] III, have been synthesized under hydrothermal condition. The relationship between their properties and structures were studied by using FTIR, UV-Vis DRS and flurescence. The FTIR showed that the vibrational frequencies of the group are related to the structure of the materials. In UV-Vis DRS spectra of compound I, there are four characteristic wide peaks at 200, 230, 260 and 350 nm corresponding to O(t) --> V, O(mu) --> Ni, O(mu) --> V charge transfer and phen's pi-pi*, respectively. The fluorescence spectra of clusters have been studies. Finally, the quantum chemistry calculation was performed by Gaussian 98 program to explain the structure characteristic of compound I.