A new two-dimensional ZnII coordination polymer based on 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and 5-nitrobenzene-1,3-dicarboxylic acid: synthesis, crystal structure and physical properties

A 3D 2-fold interpenetrating Cu(II) coordination polymer based on 4,4′-oxybis(benzoic acid) and 1,3-bis(2-methyl-imidazol-1-yl) benzene exhibiting photocatalytic properties

A new Cu(II) complex, [Cu2(1,3-BMIB)(OBA)2] n (1) (1,3-BMIB = 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene, H2OBA = 4,4′-oxybis(benzoic acid)) was hydrothermally synthesized and has been structurally characterized. Complex 1 possesses a 3D 2-fold interpenetrating framework based on [Cu(OBA)] n layers with a Schläfli symbol {412.63}. Complex 1 displays excellent photocatalytic properties in the degradation of methylene blue (MB) and rhodamine B (RhB).

A new ZnII metallocryptand with unprecedented diflexure helix induced by V-shaped diimidazole building blocks

Taking advantage of V-shaped ligands, a Zn^II metallocryptand, namely {[Zn₂(didp)₂(m-bdc)₂]}_n, (1) [didp = 2,8-di(1H-imidazol-1-yl)-dibenzothiophene and m-H₂bdc = isophthalic acid], has been hydrothermally synthesized. Single-crystal X-ray diffraction analysis reveals a 26-membered butterfly-type metallomacrocycle [Zn₂(didp)₂]. One m-bdc^2- ligand bridges [Zn₂(didp)₂] units to form a laterally non-symmetric [Zn₂(didp)₂(m-bdc)] metallocryptand with an exo-exo conformation. Another crystallographically independent m-bdc^2- functions as a secondary synthon to bridge discrete metallocryptands into a 1D zigzag chain architecture. Undoubtedly, the choice of two matched ligands in this work is crucial for metallocryptand construction and structure expansion. Interestingly, a rare helical chain with two flexures in one single L and/or R strand is observed. Another important feature is the C-O...π interactions, by which the dimensionality extension of (1) can be induced. Fluorescence measurements and density functional theory (DFT) calculations illustrate that the emission of (1) can probably be attributed to ligand-to-ligand charge transfer (LLCT).

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^II coordination frameworks, namely, poly[tris{μ-1,4-bis[(1H-imidazol-1-yl)methyl]benzene-κ²N³:N^3'}tetrakis(nitrato-κ²O,O')dicadmium], [Cd₂(NO₃)₄(C₁₄H₁₄N₄)₃]_n, (I), and poly[[bis{μ₃-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κ³N³:N^3':N^3''}cadmium] hexafluorosilicate], {[Cd(C₁₈H₁₈N₆)₂](SiF₆)}_n, (II), have been synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. In polymer (I), the 1,4-bis[(1H-imidazol-1-yl)methyl]benzene ligand bridges Cd²⁺ ions with a distorted seven-coordinated pentagonal bipyramidal geometry, forming a one-dimensional ladder chain, and the nitrate anions coordinate to the Cd²⁺ ions in a terminal bidentate fashion. In the crystal, adjacent chains are further connected by C-H...O hydrogen bonds to generate a two-dimensional (2D) supramolecular structure. Polymer (II) exhibits a 2D layered structure in which 1,3,5-tris[(1H-imidazol-1-yl)methyl] benzene ligands join Cd²⁺ centres having a six-coordinated octahedral structure. The layers are connected by hexafluorosilicate anions via C-H...F hydrogen-bond interactions, giving rise to a three-dimensional supramolecular network structure in the solid state. In addition, powder X-ray diffraction (PXRD) patterns were recorded, thermogravimetric analyses (TGA) carried out and fluorescence properties investigated.