Gui-Mei Tang

Metal-directed assembly of coordination polymers with the versatile ligand 2-(1H-benzotriazol-1-yl) acetic acid: from discrete structures to two-dimensional networks

Eight new metal coordination complexes, namely, [Co(BTA)2(H2O)4]·6H2O (1), [Ni(BTA)2(H2O)4]·6H2O (2), [Cu2(HBTA)4(BTA)2]·2H2O (3), [Ag(BTA)(H2O)]n (4), [Zn(BTA)2(H2O)]n (5), [Cd(BTA)2(H2O)]n (6), [Cu2(μ3-OH)(BTA)3]n (7), and [Mn(BTA)2(H2O)2]n (8) [HBTA = 2-(1H-benzotriazol-1-yl)acetic acid], were obtained under hydrothermal conditions, by reacting the different metal salts with HBTA. The ligand HBTA was characterized by melting point (m.p.), elemental analysis (EA), infrared spectroscopy (IR), 1H NMR, and X-ray single-crystal diffraction. Complexes 1–8 were structurally characterized by X-ray single-crystal diffraction, EA, IR, PXRD, and thermogravimetry analysis (TGA). These complexes all display low-dimensional features displaying various zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) coordination motifs. Complexes 1 and 2 are isostructural and mononuclear; they show unique decamer water clusters with bis-boat conformations, which further extend to a 1D metal–water chain. Through intermolecular hydrogen bonds, these 1D metal–water chains extend to 3D supramolecular networks. Complex 3 shows a bi-nuclear structure. Complex 4 displays a 1D tape structure. There exist weak interactions between Ag⋯Ag. Complexes 5 and 6 form a 1D linear chain bridged by BTA anions. Complex 7 exhibits a 2D layer containing tetranuclear butterfly [Cu4(CO2)4(μ3-OH)] secondary building units (SBUs). Complex 8 possesses a 2D layer and further stacks via hydrogen bonding interactions to generate a three-dimensional supramolecular architecture. These results suggest that both the coordination preferences of the metal ions and the versatile nature of this flexible ligand play a critical role in the final structures. The luminescent spectra show strong emission intensities in complexes 3, 4, 5, and 6. Complexes 3, 5 and 6 display blue photoluminescence. However, complex 4 exhibits green fluorescence. Variable-temperature magnetic susceptibility measurements reveal the existence of antiferromagnetic interactions in both 7 and 8. Additionally, the ferroelectric and second-harmonic generation (SHG) properties of 5 are discussed in detail.

A new 2-D cobalt coordination polymer with the flexible 2-(1H-imidazole-1-yl)acetate: synthesis, structure, and characterization

A new cobalt coordination polymer with linking unit 2-(1H-imidazole-1-yl)acetate (ima), [Co(ima)2] n (1), has been synthesized and structurally characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The X-ray analysis indicates that a neutral 2-D coordination polymer with (3,6) topology was obtained, which shows a 3-D supramolecular network through C–H···O weak interactions. Complex 1 displays mild antimicrobial activity against Achromobacter xylosoxidans ATCC 2706, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 90028, respectively. The magnetic and thermal gravimetric properties for 1 have been investigated and discussed.

New homochiral ferroelectric supramolecular networks of complexes constructed by chiral S-naproxen ligand

Five new homochiral supramolecular networks of complexes, namely, [Ni(L)2(H2O)6]·2H2O (1), [Cu(L)2(H2O)3]·H2O (2), [Zn(L)2(H2O)2]·H2O (3), [Cd(L)2(H2O)2]·H2O (4) and [Cd(L)2(H2O)]n (5) [L = (S)-naproxen anion], have been prepared and structurally characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis, thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. Complex 1 crystallizes in the space group P1, which is a mononuclear structure. In 1, there exists a variety of hydrogen bonding interactions, which further extend to a 3D supramolecular architecture. Complexes 2–4 crystallize in the space group C2, and all of them exhibit mononuclear structures. Intermolecular hydrogen bonding and C–H⋯π interactions are observed in complexes 2–4. Complex 5 crystallizes in the space group Cc, showing a one-dimensional chain structure. Hydrogen bonding (O–H⋯O) and weak stacking interactions (C–H⋯π) are also found. All of the complexes display significant ferroelectric properties and second harmonic generation response. Additionally, the photoluminescence spectra of complexes 3–5 have also been discussed.

Dynamic one-dimensional water in a nonporous organic solid with optics response

Dynamic transformation from a one-dimensional water tape (2T6(2)) with a boat conformation, one-dimensional water chain, to no water was observed in a benzoimidazole-based nonporous organic solid, which shows a non-linear optics and luminescence response upon one-dimensional water removal and uptake.

A 2-D nickel coordination polymer with an unsymmetric ligand, 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione

A new nickel coordination polymer was obtained from an unsymmetric building block 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione (HL6) and Ni(NO3)2 · 6H2O-afforded [Ni(L6)2(H2O)2] n (1) with a (4,4) network. Complex 1 exhibits moderate antimicrobial activity against Bacillus subtilis ATCC 6633 and Candida albicans ATCC 90028. Thermogravimetric data and magnetic moments for 1 have been investigated.

Structural and luminescent properties of a series of Cd(II) pyridyl benzimidazole complexes that exhibit extended three-dimensional hydrogen bonded networks

Abstract Five new coordination complexes, [CdI2(3-PyBim)](H2O)3 (1), [Cd(SO4)(3-PyBim)(H2O)4] (2), [CdCl2(4-PyBim)2(H2O)2] (3), [CdBr2(4-PyBim)2(H2O)2] (4) and [CdI2(4-PyBim)2(H2O)2] (5) [3-PyBim=2-Pyridin-3-yl-1H-benzoimidazole, 4-PyBim=2-Pyridin-4-yl-1H-benzoimidazole], were obtained under hydrothermal conditions and characterized by single crystal X-ray diffraction, IR, elemental analysis, and powder X-ray diffraction. All of the complexes have mononuclear structures. Among the crystal structures of these complexes, there exist a variety of intermolecular hydrogen bonding interactions and π⋯π interactions, which further extend to a 3-D supramolecular architecture. The solid state photoluminescent properties of 1–5 vary with the electronegativity of the coordination anion. Additionally, the thermogravimetric analyses of these complexes are discussed.

Syntheses, crystal structures, and luminescent properties of three metal coordination polymers based on adipic acid and 2-(pyridine-3-yl)-(1H)-benzimidazole

Three new metal coordination polymers constructed from adipic acid and 2-(pyridin-3-yl)-(1H)-benzimidazole ligands, [M(ADP)(3PBI)2(H2O)2]·2H2O (M = Ni and Co for 1 and 2, respectively) and [Cd(ADP)(3PBI)(H2O)] (3) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1H)-benzimidazole], have been synthesized by hydrothermal reactions and were characterized by X-ray single-crystal diffraction, elemental analyses, IR, powder X-ray diffraction, and thermogravimetry. Complexes 1 and 2 are isostructural. Both form a 1-D linear chain structure, which is further assembled into a 3-D supramolecular framework by π⋯π stacking and hydrogen bonding interactions. Complex 3 possesses a binuclear unit and displays a 2-D layer which is further extended to a 3-D supramolecular architecture via hydrogen bonding and other weak packing interactions. The luminescent properties of 3 were investigated in the solid state at room temperature.

Novel Acentric Organic Solids with Non-linear Optical and Ferroelectric Properties

A series of compounds obtained through one-pot three-component reaction, present non-centrosymmetric polar packing arrangement, resulting in strong second harmonic generation responses and ferroelectric behaviours.

Piperidinium 3-hydr­oxy-2-naphthoate

The crystals of the title salt, C5H12N+·C11H7O3 −, were obtained from a methanol/water solution of 3-hydroxy-2-naphthoic acid and piperidine at room temperature. In the crystal structure, the piperidinium cations display a chair conformation and link with hydroxynaphthoate anions via N—H⋯O and C—H⋯O hydrogen bonds. An intramolecular O—H⋯O interaction is also present.

Nonlinear optical and ferroelectric materials based on 1-benzyl-2-phenyl-1H-benzimidazole salts

A series of benzimidazole-based salts, obtained through the reaction of 1-benzyl-2-phenyl-1H-benzimidazole and inorganic acid, crystallize in the chiral P1 space group, which exhibit moderate second harmonic generation (SHG) responses and ferroelectric properties.