Two new cadmium(II) coordination polymers based on imidazole-containing ligands: synthesis, structural characterization and fluorescence properties.

The judicious selection of suitable ligands is vitally important in the construction of novel metal-organic frameworks (MOFs) with fascinating structures and interesting properties. Recently, imidazole-containing multidentate ligands have received much attention. Two new Cd coordination frameworks, namely, poly[tris{μ-1,4-bis[(1H-imidazol-1-yl)methyl]benzene-κN:N}tetrakis(nitrato-κO,O')dicadmium], [Cd(NO)(CHN)], (I), and poly[[bis{μ-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κN:N:N}cadmium] hexafluorosilicate], {[Cd(CHN)](SiF)}, (II), have been synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction.

New views and possibilities of antidiabetic drugs in treating and/or preventing mild cognitive impairment and Alzheimer's Disease.

Mounting evidence suggests that diabetes mellitus (DM) is associated with mild cognitive impairment (MCI), vascular dementia and Alzheimer's disease (AD). Biological, clinical and epidemiological data support a close link between DM and AD. Increasingly, studies have found that several antidiabetic agents can promote neurogenesis, and clinically ameliorate cognitive and memory impairments in different clinical settings.

A new one-dimensional Ni coordination polymer with a two-dimensional supra-molecular architecture.

A new one-dimensional Ni coordination polymer of 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene, namely -poly[[aqua-(sulfato-κ)hemi(μ-ethane-1,2-diol-κ:')[μ-1,3,5-tris-(1-imidazol-1-ylmeth-yl)benzene-κ,,]nickel(II)] ethane-1,2-diol monosolvate monohydrate], {[Ni(SO)(CHN)(CHO)(HO)]·CHO·HO} , was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The Ni cation is coordinated by three N atoms of three different 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene ligands, one O atom of an ethane-1,2-diol mol-ecule, by a sulfate anion and a water mol-ecule, forming a distorted octa-hedral NiNO coordination geometry. The tripodal 1,3,5-tris-(imidazol-1-ylmeth-yl)benzene ligands link the Ni cations, generating metal-organic chains running along the [100] direction.

A new three-dimensional manganese(II) coordination polymer based on the 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene ligand.

The self-assembly of coordination polymers and the crystal engineering of metal-organic coordination frameworks have attracted great interest, but it is still a challenge to predict and control the compositions and structures of the complexes. Employing multidentate organic ligands and suitable metal ions to construct inorganic-organic hybrid materials through metal-ligand coordination and hydrogen-bonding interactions has become a major strategy. Recently, imidazole-containing multidentate ligands that contain an aromatic core have received much attention.

PPARγ agonists regulate bidirectional transport of amyloid-β across the blood-brain barrier and hippocampus plasticity in db/db mice.

Background And Purpose: There is emerging evidence suggesting that abnormal transport of amyloid-β (Aβ) across the blood-brain barrier (BBB) is involved in diabetes-associated cognitive decline. We investigated whether PPARγ agonists restore Aβ transport across the BBB and hippocampal plasticity in db/db mice.

Experimental Approach: Efflux and influx of Aβ across the BBB were determined by stereotaxic intra-cerebral or i.

Antidiabetic drugs restore abnormal transport of amyloid-β across the blood-brain barrier and memory impairment in db/db mice.

Previous studies have shown significant changes in amyloid-β (Aβ) transport across the blood-brain barrier (BBB) under diabetic conditions with hypoinsulinemia, which is involved in diabetes-associated cognitive impairment. Present study employed db/db mice with hyperinsulinemia to investigate changes in Aβ transport across the BBB, hippocampal synaptic plasticity, and restorative effects of antidiabetic drugs. Our results showed that db/db mice exhibited similar changes in Aβ transport across the BBB to that of insulin-deficient mice.

Pretreatment with antiasthmatic drug ibudilast ameliorates Aβ 1-42-induced memory impairment and neurotoxicity in mice.

Amyloid-β peptide (Aβ) is thought to be associated with the progressive neuronal death observed in Alzheimer's disease (AD). However, effective neuroprotective approaches against Aβ neurotoxicity are unavailable. Here, we investigated possible preventive effects of ibudilast, as a pharmacologic phosphodiesterase inhibitor, currently used for treatment of inflammatory diseases such as asthma, on Aβ 1-42-induced neuroinflammatory, apoptotic responses and memory impairment.

Bis(6-nitro-1,10-phenanthrolin-1-ium) 2,5-di-carb-oxy-terephthalate.

In the structure of the title 2:1 proton-transfer compound, 2C12H8N3O2 (+)·C10H4O8 (2-), the 6-nitro-1,10-phenanthroline mol-ecules act as proton sponges, accepting protons from pyromellitic acid. The -NO2 group of one of the 6-nitro-1,10-phenanthrolin-1-ium cations is disordered and was refined with a site-occupancy ratio of 0.624 (15):0.

A novel three-dimensional Zn(II) coordination polymer with 1,3,5-tris(imidazol-1-ylmethyl)benzene and cyclohexane-1,3,5-tricarboxylate ligands.

In the Zn(II) compound poly[[bis(μ3-cyclohexane-1,3,5-tricarboxylato)bis[μ3-1,3,5-tris(imidazol-1-ylmethyl)benzene]trizinc(II)] hexahydrate], {[Zn3(C18H18N6)2(C9H9O6)2]·6H2O}n, based on mixed 1,3,5-tris(imidazol-1-ylmethyl)benzene and cyclohexane-1,3,5-tricarboxylate ligands, there are two types of crystallographically independent Zn(II) centres, one in a general position and one on a crystallographic twofold axis. They have similar fourfold distorted tetrahedral coordination geometries, ligated by two monodentate carboxylate groups from two cyclohexane-1,3,5-tricarboxylate ligands and by two N atoms from two 1,3,5-tris(imidazol-1-ylmethyl)benzene ligands. The cyclohexane-1,3,5-tricarboxylate anions link the Zn(II) cations to generate a two-dimensional layered metal-organic structure running parallel to the (201) plane.

2,9-Dimethyl-1,10-phenanthrolin-1-ium 2,4,5-tri-carb-oxy-benzoate monohydrate.

In the preparation of the title hydrated salt, C14H13N2 (+)·C10H5O8 (-)·H2O, a proton has been transfered to the 2,9-dimethyl-1,10-phenanthrolinium cation, forming a 2,4,5-tri-carb-oxy-benzoate anion. In the anion, the mean planes of the protonated carboxyl-ate groups form dihedral angles of 11.0 (5), 4.

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-κ(2) O,O')nickel(II) propane-1,2-diol monosolvate.

In the title compound, [Ni(SO4)(C12H8N2)2]·C3H8O2, the Ni(II) atom exhibits a distorted octa-hedral coordination by four N atoms from two chelating 1,10-phenanthroline ligands and two O atoms from an O,O'-bidentate sulfate group. A twofold rotation axis passes through the Ni and S atoms and the mid-point of the hydroxyl C-C bond of the propane-1,2-diol solvent mol-ecule. The dihedral angle between the two chelating N2C2 groups is 85.

Two-dimensional hydrogen-bonded supramolecular networks in the compounds of benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid) with 2,2'-biimidazole and 4,4'-dimethyl-2,2'-bipyridine.

Two products from the proton-transfer reactions of benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid, PMA) with 2,2'-biimidazole and 4,4'-dimethyl-2,2'-bipyridine, namely 2,2'-biimidazole-3,3'-diium 2,5-dicarboxybenzene-1,4-dicarboxylate, C6H8N4(2+),C10H4O8(2-), (I), and 4-methyl-2-(4-methylpyridin-2-yl)pyridinium 2,4,5-tricarboxybenzoate monohydrate, C12H13N2(+)·C10H5O8(-)·H2O, (II), have been prepared and their structures determined. Both compounds crystallize in the space group P1. The asymmetric unit of (I) is composed of two independent ion pairs.

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-κO)zinc(II) propane-1,2-diol monosolvate.

In the title compound, [Zn(SO4)(C12H8N2)2]·C3H8O2, the Zn(II) ion is in a distorted square-pyramidal coordination environment composed of four N atoms from two chelating 1,10-phenanthroline ligands and one O atom from a monodentate sulfate ligand. The Zn(II) ion lies on a twofold rotation axis. The sulfate ligand and propane-1,2-diol mol-ecules are disordered across the twofold rotation axis.

Poly[diaqua-bis-(μ-4,4'-bipyridine-κ(2) N:N')bis-(ethane-1,2-diol-κO)bis(μ-sulfato-κ(2) O:O')dicobalt(II)].

In the title compound, [Co2(SO4)2(C10H8N2)2(C2H6O2)2(H2O)2] n , there are two crystallographically independent Co(II) ions, each of which lies on a twofold rotation axis and has a slightly distorted octa-hedral environment. One Co(II) ion is coordinated by two N atoms from two bridging 4,4'-bipyridine (4,4'-bipy) ligands, two O atoms from two sulfate ions and two O atoms from aqua ligands. The second Co(II) ion is similar but with ethane-1,2-diol ligands in place of water mol-ecules.

Poly[aqua-(μ2-4,4'-bipyridine-κ(2) N:N')(ethane-1,2-diol-κO)(μ2-sulfato-κ(2) O:O')nickel(II)].

The title compound, [Ni(SO4)(C10H8N2)(C2H6O2)(H2O)] n , contains two crystallographically unique Ni(II) atoms, each lying on a twofold rotation axis and having a slightly distorted octa-hedral environment. It is isotypic with the previously reported Cu(II) analog [Zhong et al. (2011 ▶).

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-O)copper(II) butane-2,3-diol monosolvate.

The title compound, [Cu(SO4)(C12H8N2)2]·C4H10O2, is comprised of neutral monomeric complex and butane-2,3-diol solvent mol-ecules. In the complex, the Cu(II) ion is in a distorted square-pyramidal coordination environment defined by four N atoms from two chelating 1,10-phenanthroline ligands and one O atom from a monodentate sulfate anion; the O atom is at the apex. The two chelating N2C2 groups subtend a dihedral angle of 85.

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-κ(2) O,O')cobalt(II) propane-1,2-diol monosolvate.

In the title compound, [Co(SO4)(C12H8N2)2]·C3H8O2, the Co(II) atom (site symmetry 2) has a distorted octa-hedral coordination composed of four N atoms from two chelating 1,10-phenanthroline ligands and two O atoms from an O,O'-bidentate sulfate ligand, in which the S atom has site symmetry 2. The dihedral angle between the two chelating N2C2 groups is 84.46 (15)°.

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-O)copper(II) propane-1,3-diol monosolvate.

In the title compound, [Cu(SO4)(C12H8N2)2]·C3H8O2, the Cu(II) ion is bonded to two chelating 1,10-phenanthroline (phen) ligands and one O atom from a monodentate sulfate ligand in a distorted square-based pyramidal arrangement, with the O atom in a basal site. The two chelating N2C2 groups subtend a dihedral angle of 71.10 (15)°.

Bis(1,10-phenanthroline-κ(2) N,N')(sulfato-κ(2) O,O')nickel(II) butane-2,3-diol monosolvate.

In the title compound, [Ni(SO4)(C12H8N2)2]·C4H10O2, the Ni(II) ion is six-coordinated by four N atoms from two chelating 1,10-phenanthroline ligands and two O atoms from an O,O'-bidentate sulfate anion, resulting in a distorted octa-hedral geometry for the metal ion. The dihedral angle between the two chelating N2C2 groups is 83.82 (12)°.

Poly[diaqua-(μ(4)-2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ato-κ(4)O(1):O(2):O(4):O(5))(μ(2)-2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ato-κ(2)O(1):O(4))bis-(1,10-phenanthroline-κ(2)N,N')dimanganese(II)].

In the title compound, [Mn(2)(C(10)H(4)O(8))(2)(C(12)H(8)N(2))(2)(H(2)O)(2)](n), the Mn(2+) ion has a slightly distorted octa-hedral N(2)O(4) coordination geometry being coordinated by one aqua O atom, two N atoms of the chelating 1,10-phenanthroline ligand and three carboxyl O atoms from three 2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ate (H(2)btec(2-)) ligands. The H(2)btec(2-) anion exhibits two different coordination modes, viz. μ(2) and μ(4).

A novel one-dimensional Co(II) coordination polymer: catena-poly[[hexaaquacobalt(II)] [[diaquabis(sulfato-κO)cobalt(II)]-μ-4,4'-bipyridine-κ2N:N'] [[triaqua(sulfato-κO)cobalt(II)]-μ-4,4'-bipyridine-κ2N:N']].

The title compound, {[Co(H(2)O)(6)][Co(SO(4))(C(10)H(8)N(2))(H(2)O)(3)][Co(SO(4))(2)(C(10)H(8)N(2))(H(2)O)(2)]}(n), contains three crystallographically unique Co(II) centres, all of which are in six-coordinated environments. One Co(II) centre is coordinated by two bridging 4,4'-bipyridine (4,4'-bipy) ligands, one sulfate ion and three aqua ligands. The second Co(II) centre is surrounded by two N atoms of two 4,4'-bipy ligands and four O atoms, i.

Tris(1,10-phenanthroline-κ2N,N')iron(II) bis(2,4,5-tricarboxybenzoate) monohydrate and tris(2,2'-bipyridine-κ2N,N')iron(II) 2,5-dicarboxybenzene-1,4-dicarboxylate-benzene-1,2,4,5-tetracarboxylic acid-water (1/1/2).

The title compounds, tris(1,10-phenanthroline-κ(2)N,N')iron(II) bis(2,4,5-tricarboxybenzoate) monohydrate, [Fe(C(12)H(8)N(2))(3)](C(10)H(5)O(8))(2)·H(2)O, (I), and tris(2,2'-bipyridine-κ(2)N,N')iron(II) 2,5-dicarboxybenzene-1,4-dicarboxylate-benzene-1,2,4,5-tetracarboxylic acid-water (1/1/2), [Fe(C(10)H(8)N(2))(3)](C(10)H(4)O(8))·C(10)H(6)O(8)·2H(2)O, (II), were obtained during an attempt to synthesize a mixed-ligand complex of Fe(II) with an N-containing ligand and benzene-1,2,4,5-tetracarboxylic acid via a solvothermal reaction. In both mononuclear complexes, each Fe(II) metal ion is six-coordinated in a distorted octahedral manner by six N atoms from three chelating 1,10-phenanthroline or 2,2'-bipyridine ligands. In compound (I), the Fe(II) atom lies on a twofold axis in the space group C2/c, whereas (II) crystallizes in the space group P2(1)/n.

Diaqua-bis-(1,10-phenanthroline-κN,N')cadmium sulfate hexa-hydrate.

The title compound, [Cd(C(12)H(8)N(2))(2)(H(2)O)(2)]SO(4)·6H(2)O, was obtained unexpectedly during an attempt to synthesize a cadmium complex with bidentate bridging sulfate ligands via hydro-thermal synthesis. The Cd(II) metal ion is six-coordinated by two chelating 1,10-phenanthroline ligands and two water mol-ecules, resulting in a distorted octa-hedral geometry for the metal ion. The two chelating N(2)C(2) groups are almost perpendicular to each other [dihedral angle = 86.

Tris(1,10-phenanthroline-κN,N')nickel(II) bis-(2,4,5-tricarb-oxy-benzo-ate) monohydrate.

In the title compound, [Ni(C(12)H(8)N(2))(3)](C(10)H(5)O(8))(2)·H(2)O, the Ni(II) cation is coordinated by six N atoms of the three bidentate chelating 1,10-phenanthroline ligands in a slightly distorted octa-hedral coordination geometry. The Ni-N bond lengths range from 2.074 (2) to 2.