Effects of two benzenedicarboxylic acids on the construction of CdII coordination polymers incorporating a flexible N-donor ligand.

Compared with the monomorphic type of ligand, combining mixed ligands in one coordination polymer offers greater tunability of the structural framework. Employment of N-heterocyclic ligands and aromatic polycarboxylates is an effective approach for the construction of metal-organic frameworks (MOFs). Two new coordination polymers incorporating both 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) and benzenedicarboxylic acid isomers, namely, catena-poly[[[di-µ-chlorido-bis[(2-carboxybenzoato-κ2O1,O1')cadmium(II)]]-bis{µ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ2N:N'}] dihydrate], {[Cd(C8H5O4)Cl(C11H10N4)]·H2O}n, (I), and poly[[aqua(µ2-benzene-1,3-dicarboxylato-κ3O1,O1':O3){µ2-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ2N:N'}cadmium(II)] dihydrate], {[Cd(C8H4O4)(C11H10N4)(H2O)]·2H2O}n, (II), have been prepared and structurally characterized by single-crystal X-ray diffraction. In polymer (I), imb ligands bridge CdII ions, forming a one-dimensional chain, and 2-carboxybenzoate anions coordinate to the CdII ions in a terminal fashion. Polymer (II) exhibits a two-dimensional network structure in which imb ligands and the benzene-1,3-dicarboxylate anions join CdII ions co-operatively. This indicates that changing of the aromatic dicarboxylic acids can result in polymers with different compositions and architectures. Moreover, their IR spectra, PXRD (powder X-ray diffraction) patterns, thermogravimetric analyses and fluorescence properties were also investigated.

A new one-dimensional CdII coordination polymer incorporating 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylate).

Imidazole-4,5-dicarboxylic acid (H3IDC) and its derivatives are widely used in the preparation of new coordination polymers owing to their versatile bridging coordination modes and potential hydrogen-bonding donors and acceptors. A new one-dimensional coordination polymer, namely catena-poly[[diaquacadmium(II)]-µ3-2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylato)], [Cd(C16H6N4O8)0.5(H2O)2]n or [Cd(H2Phbidc)1/2(H2O)2]n, has been synthesized by the reaction of Cd(OAc)2·2H2O (OAc is acetate) with 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylic acid) (H6Phbidc) under solvothermal conditions. In the polymer, one type of Cd ion (Cd1) is six-coordinated by two N atoms and two O atoms from one H2Phbidc4- ligand and by two O atoms from two water molecules, forming a significantly distorted octahedral CdN2O4 coordination geometry. In contrast, the other type of Cd ion (Cd2) is six-coordinated by two N atoms and two O atoms from two symmetry-related H2Phbidc4- ligands and by two O atoms from two symmetry-related water molecules, leading to a more regular octahedral coordination geometry. The Cd1 and Cd2 ions are linked by H2Phbidc4- ligands into a one-dimensional chain which runs parallel to the b axis. In the crystal, the one-dimensional chains are connected through hydrogen bonds, generating a two-dimensional layered structure parallel to the ab plane. Adjacent layers are further linked by hydrogen bonds, forming a three-dimensional structure in the solid state.

A new two-dimensional managnese(II) coordination polymer constructed by 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylate).

In recent years, N-heterocyclic carboxylate ligands have attracted much interest in the preparation of new coordination polymers since they contain N-atom donors, as well as O-atom donors, and have a rich variety of coordination modes which can lead to polymers with intriguing structures and interesting properties. A new two-dimensional coordination polymer, namely poly[[µ3-2,2'-(1,2-phenylene)bis(4-carboxy-1H-imidazole-5-carboxylato)-κ6O4,N3,N3',O4':O5:O5']manganese(II)], [Mn(C16H8N4O8)]n or [Mn(H4Phbidc)]n, has been synthesized by the reaction of Mn(OAc)2·4H2O (OAc is acetate) with 2,2'-(1,2-phenylene)bis(1H-imidazole-4,5-dicarboxylic acid) (H6Phbidc) under solvothermal conditions. In the polymer, each MnII ion is six-coordinated by two N atoms from one H4Phbidc2- ligand and by four O atoms from three H4Phbidc2- ligands, forming a significantly distorted octahedral MnN2O4 coordination geometry. The MnII ions are linked by hexadentate H4Phbidc2- ligands, leading to a two-dimensional structure parallel to the ac plane. In the crystal, adjacent layers are further connected by N-H...O hydrogen bonds, forming a three-dimensional structure in the solid state.

A new two-dimensional CdII coordination polymer based on 2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole and benzene-1,2-dicarboxylate: synthesis, crystal structure and characterization.

In the construction of coordination polymers, many factors can influence the formation of the final architectures, such as the nature of the metal centres, the organic ligands and the counter-anions. In the coordination polymer poly[aqua(µ-benzene-1,2-dicarboxylato-κ4O1,O1':O2,O2')[µ-2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole-κ2N2:N3]cadmium(II)], [Cd(C12H12N4)(C8H4O4)(H2O)]n or [Cd(immb)(1,2-bdic)(H2O)]n, each CdII ion is seven-coordinated by two N atoms from two symmetry-related 2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole (immb) ligands, by four O atoms from two symmetry-related benzene-1,2-dicarboxylate (1,2-bdic2-) ligands and by one water molecule, leading to a CdN2O5 distorted pentagonal bipyramidal coordination environment. The immb and 1,2-bdic2- ligands bridge CdII ions and form a two-dimensional network structure. O-H...O and N-H...O hydrogen bonds stabilize the structure. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviour and fluorescence properties of the title polymer have been investigated.

A new three-dimensional zinc(II) coordination polymer involving 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole and benzene-1,4-dicarboxylate ligands.

Metal-organic frameworks (MOFs) based on multidentate N-heterocyclic ligands involving imidazole, triazole, tetrazole, benzimidazole, benzotriazole or pyridine present intriguing molecular topologies and have potential applications in ion exchange, magnetism, gas sorption and storage, catalysis, optics and biomedicine. The 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligand has four potential N-atom donors and can act in monodentate, chelating, bridging and tridentate coordination modes in the construction of complexes, and can also act as both a hydrogen-bond donor and acceptor. In addition, the tmb ligand can adopt different coordination conformations, resulting in complexes with helical structures due to the presence of the flexible methylene spacer. A new three-dimensional coordination polymer, poly[[bis(µ2-benzene-1,4-dicarboxylato)-κ(4)O(1),O(1'):O(4),O(4');κ(2)O(1):O(4)-bis{µ2-2-[(1H-1,2,4-triazol-1-yl)methyl-κN(4)]-1H-benzimidazole-κN(3)}dizinc(II)] trihydrate], {[Zn(C8H4O4)(C10H9N5)]·1.5H2O}n, has been synthesized by the reaction of ZnCl2 with tmb and benzene-1,4-dicarboxylic acid (H2bdic) under solvothermal conditions. There are two crystallographically distinct bdic(2-) ligands [bdic(2-)(A) and bdic(2-)(B)] in the structure which adopt different coordination modes. The Zn(II) ions are bridged by tmb ligands, leading to one-dimensional helical chains with different handedness, and adjacent helices are linked by bdic(2-)(A) ligands, forming a two-dimensional network structure. The two-dimensional layers are further connected by bdic(2-)(B) ligands, resulting in a three-dimensional framework with the topological notation 6(6). The IR spectra and thermogravimetric curves are consistent with the results of the X-ray crystal structure analysis and the title polymer exhibits good fluorescence in the solid state at room temperature.

Dichloridobis{2-[(1H-1,2,4-triazol-1-yl)meth-yl]-1H-benzimidazole-κN (3)}-zinc(II).

In the title complex, [ZnCl2(C10H9N5)2], the Zn(II) ion is coordinated by two N atoms from two 2-[(1H-1,2,4-triazol-1-yl)meth-yl]-1H-benzimidazole (tmb) ligands and by two chloride ligands in a slightly distorted tetra-hedral geometry. In the tmb ligands, the benzimidazole rings systems are essentially planar, with maximum deviations from the mean plane of 0.021 (3) and 0.030 (3) Å, and form dihedral angles of 73.2 (2) and 83.5 (2)° with the triazole rings. In the crystal, N-H⋯N hydrogen bonds link complex mol-ecules into chains along [010]. In addition, weak C-H⋯Cl and C-H⋯N hydrogen bonds complete a three-dimensional network. Two weak intra-molecular C-H⋯Cl hydrogen bonds are also observed.

Diaqua-bis-{1-[(1H-benzimidazol-2-yl)meth-yl]-1H-imidazole-κN(3)}dichlorido-cadmium hexa-hydrate.

In the title complex, [CdCl(2)(C(11)H(10)N(4))(2)(H(2)O)(2)]·6H(2)O, the Cd(II) atom is located on a twofold rotation axis and is coordinated by two N atoms from two 1-[(1H-benzimidazol-2-yl)meth-yl]-1H-imidazole ligands and two water O atoms in equatorial positions and by two Cl atoms in axial positions, leading to an elongated octa-hedral environment. The two coordinating and two of the lattice water mol-ecules are also located on twofold rotation axes. In the crystal, complex mol-ecules and solvent water mol-ecules are linked through a complex inter-molecular N-H⋯O, O-H⋯N, O-H⋯O and O-H⋯Cl hydrogen-bonding scheme into a three-dimensional network.

Poly[[tetra-aqua-bis-(µ(3)-5-carboxybenzene-1,2,4-tri-carboxyl-ato)tricadmium] tetra-hydrate].

There are three independent Cd(II) ions in the title complex, {[Cd(3)(C(10)H(3)O(8))(2)(H(2)O)(4)]·4H(2)O}(n), one of which is coordinated by four O atoms from three 5-carboxybenzene-1,2,4-tri-carboxyl-ate ligands and by two water mol-ecules in a distorted octa-hedral geometry. The second Cd(II) ion is coordinated by five O atoms from four 5-carboxybenzene-1,2,4-tri-carboxyl-ate ligands and by one water mol-ecule also in a distorted octa-hedral geometry while the third Cd(II) ion is coordinated by five O atoms from three 5-carboxybenzene-1,2,4-tri-carboxyl-ate ligands and by one water mol-ecule in a highly distorted octa-hedral geometry. The 5-carboxybenzene-1,2,4-tri-carboxyl-ate ligands bridge the Cd(II) ions, resulting in the formation of a three-dimensional structure. Intra- and inter-molecular O-H⋯O hydrogen bonds are present throughout the three-dimensional structure.

Poly[[diaqua-bis-(µ(3)-3,5-dicarb-oxy-benzo-ato-κ(3)O(1):O(3):O(5))bis-(µ(3)-5-carb-oxy-ben-zene-1,3-dicarboxyl-ato-κ(3)O(1):O(3):O(5))tetrakis(methylformamide-κO)tri-man-ganese(II)] dimethyl-formamide tetra-solvate].

In the title complex, {[Mn(3)(C(9)H(4)O(6))(2)(C(9)H(5)O(6))(2)(C(3)H(7)NO)(4)(H(2)O)(2)]·4C(3)H(7)NO}(n), one Mn(II) ion sits on an inversion center, and is six-coordinated by four O atoms from four anions (monoanionic and dianionic) derived from benzene-1,3,5-tricarboxylic acid and by two dimethyl-formamide (DMF) mol-ecules in a slightly distorted octa-hedral geometry. The other Mn(II) ion is six-coordinated by four O atoms from four monoanionic and dianionic ligands, one DMF mol-ecule and one water mol-ecule in a distorted octa-hedral geometry. The monoanionic and dianionic ligands bridge the Mn(II) ions, resulting in the formation of a layered structure parallel to (111) in which all of the carboxyl-ate groups of the anionic ligands coordinate the Mn(II) ions in a monodentate manner. Intra- and inter-molecular O-H⋯O hydrogen bonds are present in the structure.

A new Ag complex based on 1-[(1H-benzimidazol-1-yl)meth-yl]-1H-1,2,4-triazole.

In the title complex, bis-{µ-1-[(1H-benzimidazol-1-yl)meth-yl]-1H-1,2,4-triazole}disilver(I) dinitrate, [Ag(2)(C(10)H(9)N(5))(2)](NO(3))(2), the Ag(I) ion is nearly linearly coordinated [N-Ag-N angle is 155.72 (14)°] by two 1-[(1H-benzimidazole-1-yl)meth-yl]-1H-1,2,4-triazole (bmt) ligands. In addition, two bmt ligands link two Ag(I) ions, forming a dinuclear unit with an Ag⋯Ag distance of 5.0179 (15) Å. The whole complex is generated by an inversion centre. The dinuclear units and the NO(3) (-) counter-ions are connected by N-H⋯O hydrogen bonds and weak Ag⋯O inter-actions [2.831 (5), 2.887 (5) and 2.908 (5) Å], leading to a three-dimensional structure.

Bis[2-(2-fur-yl)-1-(2-furylmeth-yl)-1H-benzimidazole-κN]diiodidocadmium.

In the title complex, [CdI(2)(C(16)H(12)N(2)O(2))(2)], the Cd(II) atom is located on a twofold rotation axis and is four-coordinated by two N atoms from symmetry-related 2-(2-fur-yl)-1-(2-furyl-meth-yl)-1H-benzimidazole ligands and two I atoms in a distorted tetra-hedral configuration. The benzimidazole rings in adjacent mol-ecules are parallel, with an average inter-planar distance of 3.486 Å. The I atom is disordered over two sites in a 0.85 (5):0.15 (5) ratio.

catena-Poly[[chloridocadmium(II)]bis-{µ-1-[(2-ethyl-1H-imidazol-1-yl)meth-yl]-1H-benzotriazole}[chloridocadmium(II)]di-µ-chlorido].

In the polymeric title complex, [CdCl(2)(C(12)H(13)N(5))](n), the Cd(II) atom is five-coordinated by two N atoms from two bridging 1-[(2-ethyl-1H-imidazol-1-yl)meth-yl]-1H-benzotriazole (bmei) ligands, two bridging Cl atoms and one terminal Cl atom in a distorted trigonal-bipyramidal geometry. The Cd(II) atoms are connected alternately by the Cl atoms and bmei ligands, leading to a zigzag chain extending parallel to [011]. π-π inter-actions, with a centroid-centroid distance of 3.3016 (3) Å, help to stabilize the crystal packing.

Diaqua-[5,5'-dicarb-oxy-2,2'-(propane-1,3-di-yl)bis-(1H-imidazole-4-carboxyl-ato)]manganese(II).

The complex mol-ecule of the title compound, [Mn(C(13)H(10)N(4)O(8))(H(2)O)(2)] or [Mn(H(4)pbidc)(H(2)O)(2)] (H(6)pbidc = 2,2'-(propane-1,3-di-yl)bis-(1H-imidazole-4,5-dicarb-oxy-lic acid), has 2 symmetry with the twofold rotation axis running through the Mn(2+) cation and the central C atom of the propanediyl unit. The cation is six-coordinated by two N atoms and two O atoms from one H(4)pbidc(2-) anion and two water O atoms in a considerably distorted octa-hedral coordination. In the crystal, adjacent mol-ecules are linked through O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network.

A new copper(II) complex based on 1-[(1H-benzotriazol-1-yl)meth-yl]-1H-1,2,4-triazole.

The title complex, tetra-aqua-{1-[(1H-benzotriazol-1-yl)meth-yl]-1H-1,2,4-triazole-κN(4)}(sulfato-κO)copper(II) sesquihydrate, [Cu(SO(4))(C(9)H(8)N(6))(H(2)O)(4)]·1.5H(2)O, is composed of one copper atom, one 1-[(2H-benzotriazol-1-yl)meth-yl]-1-H-1,2,4-triazole (bmt) ligand, one sulfate ligand, four coordin-ated water mol-ecules and one and a half uncoordinated water mol-ecules. The Cu(II) atom is six-coordinated by one N atom from a bmt ligand and five O atoms from the monodentate sulfate ligand and four water mol-ecules in a distorted octa-hedral geometry. In the crystal, adjacent mol-ecules are linked through O-H⋯O and O-H⋯N hydrogen bonds involving the sulfate anion and the coordin-ated and uncoordinated water mol-ecules into a three-dimensional network.

Bis[4-(2-hy-droxy-benzyl-idene-amino)-benzoato-κO]tetra-kis-(methanol-κO)cadmium.

In the title mononuclear complex, [Cd(C(14)H(10)NO(3))(2)(CH(3)OH)(4)], the Cd(2+) cation is situated on an inversion centre. It exhibits a distorted octa-hedral coordination, defined by two carboxyl-ate O atoms from two monodentate anions and by four O atoms from four methanol mol-ecules. The crystal structure comprises intra-molecular O-H⋯O and O-H⋯N, and inter-molecular O-H⋯O hydrogen bonds. The latter help to construct a layered structure extending parallel to (100).

Poly[[tetra-kis-(µ-2-anilinobenzoato-κO:O')tetra-µ(1,1,1)-azido-tetra-µ(1,1)-azido-octa-methano-lhexa-nickel(II)] methanol hexa-solvate].

The crystal structure of the title compound, [Ni(6)(C(13)H(10)NO(2))(4)(N(3))(8)(CH(3)OH)(8)]·6CH(3)OH, consists of a centrosymmetric hexa-nuclear [Ni(II) (6)(C(13)H(10)NO(2))(4)(N(3))(8)(CH(3)OH)(8)] mol-ecule and six methanol solvent mol-ecules. In the hexa-nuclear unit, the six octa-hedrally coordinated Ni(II) atoms are linked by four µ(1,1,1)-azide and four µ(1,1)-azide bridges, forming a face-sharing Ni(6)N(8) tetra-cubane-like unit with four missing corners. The Ni(II) atoms are further bridged by four µ(1,2)-carboxalate groups. Neighbouring hexa-nuclear units are connected via N-H⋯O hydrogen-bonding inter-actions into a three-dimensional structure. Although the H atoms of the methanol OH groups could not be located, O⋯N/O contacts between 2.65 and 2.86 Šsuggest that these mol-ecules participate in hydrogen bonding.

The effects of grafting of 2-pyridyl to [Ru(bpy)(2)(Hpip)](2+) on acid-base and DNA-binding properties: experimental and DFT studies.

A new Ru(II) complex of [Ru(bpy)(2)(Hpip)](2+) {bpy = 2,2'bipyridine; Hppip = 2-(4-(pyridin-2-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} has been synthesized by grafting of 2-pyridyl to parent complex [Ru(bpy)(2)(Hpip)](2+) {Hppip = 2-(4-phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline}. The acid-base properties of [Ru(bpy)(2)(Hpip)](2+) studied by UV-visible and luminescence spectrophotometric pH titrations, revealed off-on-off luminescence switching of [Ru(bpy)(2)(Hpip)](2+) that was driven by the protonation/deprotonation of the imidazolyl and the pyridyl moieties. The complex was demonstrated to be a DNA intercalator with an intrinsic DNA binding constant of (5.56 ± 0.2) x 10(5) M-1 in buffered 50 mM NaCl, as evidenced by UV-visible and luminescence titrations, reverse salt effect, DNA competitive binding with ethidium bromide, steady-state emission quenching by [Fe(CN)6]4-, DNA melting experiments and viscosity measurements. The density functional theory method was also used to calculate geometric/electronic structures of the complex in an effort to understand the DNA binding properties. All the studies indicated that the introduction of 2-pyridyl onto Hpip ligand is more favorable for extension of conjugate plane of the main ligand than that of phenyl, and for greatly enhanced ct-DNA binding affinity accordingly.

Highly selective acetate optical sensing of a ruthenium(II) complex carrying imidazole and indole groups.

The effects of addition of F(-), Cl(-), Br(-), I(-), NO(3)(-), H(2)PO(4)(-), and OAc(-) on the UV-vis and emission spectra of Ru(II) complex [Ru(bpy)(2)(H(2)iip)](ClO(4))(2) {bpy=2,2'-bipyridyl, H(2)iip=2-indole-3-yl-imidazole[4,5-f][1,10]-phenanthroline} in dimethyl sulfone were studied. The Ru(II) complex was evidenced to be a highly selective optical sensor for OAc(-). Addition of OAc(-) elicited a distinct change in color from yellow to light orange which can be detected by naked-eye, and an almost vanished emission of the Ru(II) complex at a much lower concentration of OAc(-) than those of the other anions.

Azido-{2-[bis-(2-hy-droxy-eth-yl)amino]-ethano-lato-κN,O,O',O''}cobalt(II).

In the title complex, [Co(C(6)H(14)NO(3))(N(3))] or [Co(teaH(2))N(3)], the Co(II) atom resides in a trigonal-bipymidal O(3)N(2) environment formed by three O atoms and one N atom from a simply deprotonated tetra-dentate triethano-lamine ligand, and one N atom from an azide ligand. The O atoms define the equatorial plane whereas both N atoms are in axial positions. The mononuclear units are linked through O-H⋯O hydrogen-bonding inter-actions between the ethanol OH groups and the ethano-late O atom of a neighbouring complex into chains running parallel to [010].

catena-Poly[[(acetato-κO,O')(methanol-κO)cadmium(II)]-µ-[1,2-bis-(1H-benzimid-azol-2-yl)ethane]-κN:N-[(acetato-κO,O')(methanol-κO)cadmium(II)]-di-µ-chlorido].

In the title complex, [Cd(2)(CH(3)COO)(2)Cl(2)(C(16)H(14)N(4))(CH(3)OH)(2)](n), the Cd(II) atom is six-coordinated by one N atom from a centrosymmetric bridging 1,2-bis-(2,2'-1H-benzimidazol-2-yl)ethane (bbe) ligand, two O atoms from a chelating acetate ligand, one O atom from a methanol mol-ecule and two bridging Cl atoms in a distorted octa-hedral geometry. The Cd(II) atoms are connected alternately by the Cl atoms and bbe ligands, leading to a chain along [001]. These chains are further linked by O-H⋯O hydrogen bonds. Intra-chain N-H⋯O hydrogen bonds are observed.