Syntheses, structures, and properties of two 2-D Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and polycarboxylate ligands

Synthesis, molecular structure and BSA-binding properties of a new binuclear Cd(II) complex based on 2-(1H-tetrazol-1-methyl)-1H-imidazole-4,5-dicarboxylic acid

A new binuclear Cd(II) complex, [Cd2(H2tmidc)4(H2O)2]·6H2O (1) based on 2-(1H-tetrazol-1-methyl)-1H-imidazole-4,5-dicarboxylic acid (H3tmidc) has been synthesized and structurally characterized. The single-crystal X-ray diffraction analysis has revealed that there are two crystallographically distinct H2tmidc– anions in complex 1, one of which is coordinated to Cd(II) ion in a terminal fashion, while the other acts as a bis-connector linking two Cd(II) cations to form the dinuclear structure. The dimeric units are stabilized by intra-molecular O–H···O hydrogen bonds and π-π stacking interactions and are further connected into a three-dimensional supramolecular architecture through inter-molecular hydrogen bonds and π-π stacking interactions. The interactions of complex 1 with bovine serum albumin (BSA) were analyzed by fluorescence measurements under physiological conditions. The results have indicated that the fluorescence intensity of BSA was decreased considerably upon the addition of complex 1 through a static quenching mechanism. The synchronous fluorescence spectrum suggested that the interaction of complex 1 with BSA affects the conformations of tryptophan and tyrosine residues and thereby has an influence on the conformation of BSA.

Crystal structure of catena-poly[diaqua-bis(3-(4-trifluoromethyl-phenyl)-acrylato-κO 1)-(μ2-1,4-bis(1-imidazolyl)benzene-κ2 N 3:N3′)cobalt(II)], C32H26CoF6N4O6

C32H26CoF6N4O6, triclinic, P1̄ (no. 2), a = 5.4881(3) Å, b = 11.6495(6) Å, c = 13.1533(6) Å, α = 84.979(2)°, β = 84.370(2)°, γ = 80.602(2)°, V = 823.46(7) Å3, Z = 1, R gt(F) = 0.0381, wR ref(F 2) = 0.1069, T = 293(2) K.

The crystal structure of bis(1H-benzo[d]imidazol-2-amine-κN)-diiodidocadmium(II), C14H14CdI2N6

C14H14CdI2N6, triclinic, P1̄ (no. 2), a = 7.9247(5) Å, b = 8.9507(5) Å, c = 13.5143(8) Å, α = 92.428(2)°, β = 92.085(3)°, γ = 98.871(3)°, V = 945.38(10) Å3, Z = 2, R gt(F) = 0.0281, wR ref(F 2) = 0.0653, T = 298(2) K.

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,O^1':O²,O^2')[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 Cd^II 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-bdic^2-) ligands and by one water molecule, leading to a CdN₂O₅ distorted pentagonal bipyramidal coordination environment. The immb and 1,2-bdic^2- ligands bridge Cd^II 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 one-dimensional Cd(II) coordination polymer with a two-dimensional layered structure incorporating 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and benzene-1,2-dicarboxylate ligands

The N-heterocyclic ligand 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) has a rich variety of coordination modes and can lead to polymers with intriguing structures and interesting properties. In the coordination polymer catena-poly[[cadmium(II)-bis[μ-benzene-1,2-dicarboxylato-κ(4)O(1),O(1'):O(2),O(2')]-cadmium(II)-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole}-κ(2)N(2):N(3);κ(2)N(3):N(2)] dimethylformamide disolvate], {[Cd(C8H4O4)(C11H10N4)]·C3H7NO}n, (I), each Cd(II) ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from two symmetry-related benzene-1,2-dicarboxylate (1,2-bdic(2-)) ligands and two N atoms from two symmetry-related imb ligands. Two Cd(II) ions are connected by two benzene-1,2-dicarboxylate ligands to generate a binuclear [Cd2(1,2-bdic)2] unit. The binuclear units are further connected into a one-dimensional chain by pairs of bridging imb ligands. These one-dimensional chains are further connected through N-H...O hydrogen bonds and π-π interactions, leading to a two-dimensional layered structure. The dimethylformamide solvent molecules are organized in dimeric pairs via weak interactions. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.

A new one-dimensional Zn(II) coordination polymer based on 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and benzene-1,2-dicarboxylate

Multidentate N-heterocyclic compounds form a variety of metal complexes with many intriguing structures and interesting properties. The title coordination polymer, catena-poly[zinc(II)-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole}-κ(2)N(3):N(3');N(3'):N(3)-zinc(II)-bis(μ-benzene-1,2-dicarboxylato)-κ(2)O(1):O(2);κ(3)O(1),O(1'):O(2)], [Zn2(C8H4O4)2(C11H10N4)2]n, has been synthesized by the reaction of Zn(NO3)2 with 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) and benzene-1,2-dicarboxylic acid (H2bdic) under hydrothermal conditions. There are two crystallographically distinct imb ligands [imb(A) and imb(B)] in the structure which adopt very similar coordination geometries. The imb(A) ligand bridges two symmetry-related Zn1 ions, yielding a binuclear [(Zn1)2{imb(A)}2] unit, and the imb(B) ligand bridges two symmetry-related Zn2 ions resulting in a binuclear [(Zn2)2{imb(B)}2] unit. The above-mentioned binuclear units are further connected alternately by pairs of bridging bdic(2-) ligands, forming an infinite one-dimensional chain. These one-dimensional chains are further connected through N-H···O hydrogen bonds, leading to a two-dimensional layered structure. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.

A new two-dimensional ZnII coordination polymer constructed by a multidentate N-heterocyclic ligand and 5-carboxybenzene-1,3-dicarboxylate

In the coordination polymer, poly[[{μ-1-[(1H-benzimidazol-2-yl)methyl]-1H-imidazole-κ(2)N:N'}(μ-5-carboxybenzene-1,3-dicarboxylato-κ(2)O(1):O(3))zinc(II)] dimethylformamide monosolvate pentahydrate], {[Zn(C9H4O6)(C11H10N4)]·C3H7NO·5H2O}n, the Zn(II) ion is coordinated by two N atoms from two symmetry-related 1-[(1H-benzimidazol-2-yl)methyl]-1H-imidazole (bmi) ligands and two O atoms from two symmetry-related 5-carboxybenzene-1,3-dicarboxylate (Hbtc(2-)) ligands in a slightly distorted tetrahedral geometry. The Zn(II) ions are bridged by Hbtc(2-) and bmi ligands, leading to a 4-connected two-dimensional network with the topological notation (4(4).6(2)). Adjacent layers are further connected by 12 kinds of hydrogen bonds and also by π-π interactions, resulting in a three-dimensional supramolecular architecture in the solid state.