Hydrothermal Syntheses, Crystal Structures, and Characteristics of a Series of Cd−btx Coordination Polymers (btx = 1,4-Bis(triazol-1-ylmethyl)benzene)

Distinct structures of coordination polymers incorporating flexible triazole-based ligand: topological diversities, crystal structures and property studies

Six new coordination polymers, namely {[Zn(btec)(0.5)(btmb)]·2H(2)O}(n) (1), {[Co(btec)(0.5)(btmb)(H(2)O)]·3H(2)O}(n) (2), {[Cu(btec)(0.5)(btmb)]·H(2)O}(n) (3), {[Cu(4)(btc)(4)(btmb)(4)]·H(2)O}(n) (4), {[Co(3)(bta)(2)(btmb)(2)]·2H(2)O}(n) (5), [Co(Hbta)(btmb)](n) (6) (H(4)btec = 1,2,4,5-benzenetetracarboxylate, H(3)btc = 1,3,5-benzenetricarboxylate, H(3)bta = 1,2,4-benzenetricarboxylate and btmb = 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been successfully synthesized under hydrothermal conditions. All these complexes were structurally determined by single-crystal X-ray diffraction, elemental analysis, IR, TGA and XRD. Crystal structural analysis reveals that 1 is the first example of an unusual 3D framework with (8(6)) topology containing a 2D molecular fabric structure. Complex 2 exhibits a 3D NbO network with (6(4)·8(2)) topology. In 3, Cu(II) ions are coordinated by anti-conformational btmb ligands to form left- and right-handed double helices, which are further bridged by the 4-connected btec(4-) anions to give a 3D porous network. Complex 4 presents a rare 3D gra network structure with (6(3))(6(9)·8) topology. 5 and 6 were obtained through controllable pH values of solution, 5 features a scarce binodal (3,8)-connected tfz-d framework with the trinuclear Co(II) clusters acting as nodes, whereas 6 has an extended 2D 4(4) grid-like layer and the adjacent 2D layers are interconnected by strong hydrogen bonding interactions into a 3D supramolecular framework. The structural diversities indicate that distinct organic acid ligands, the nature of metal ions and the pH value play crucial roles in modulating the formation of the resulting coordination complexes and the connectivity of the ultimate topological nets. Moreover, magnetic susceptibility measurement of 5 indicates the presence of weak ferromagnetic interactions between the Co(II) ions bridged by carboxylate groups.

Bis{1-[(1H-benzimidazol-1-yl)methyl-κN3]-1H-1,2,3,4-tetrazole}silver(I) nitrate

In the title salt, [Ag(C₉H₈N₆)₂]NO₃, the central Ag^I atom is linearly coordinated by the N atoms [171.97 (8)°] from two 1-[(benzimidazol-1-yl)meth­yl]-1H-1,2,3,4-tetra­zole ligands. The benzimidazole rings in adjacent mol­ecules are parallel with an average inter­planar distance of 3.461 Å; adjacent mol­ecules are linked through N—H⋯O hydrogen bonds into a linear chain along the b-axis direction.

1-{4-[(1H-1,2,4-Triazol-1-yl)meth-yl]benz-yl}-1H-1,2,4-triazol-4-ium perchlorate

In the crystal structure of the title compound, C₁₂H₁₃N₆⁺·ClO₄⁻, the cation, located about an inversion center, is monoprotonated, and one H atom is disordered over two sites on N atoms of the two triazole rings, each with an occupancy factor of 0.5. The perchlorate anion has C₂ symmetry, the Cl atom and one O atom lying on the twofold rotation axis; the anion is thus disordered over two sites of equal occupancy. In the cation, the triazole ring makes a dihedral angle of 84.75 (7)° with the plane of the benzene ring. In the crystal, inter­molecular N—H⋯N hydrogen bonding between the triazole and triazolium rings links the cations into a wave-like supra­molecular chain. Weak inter­molecular C—H⋯N and C—H⋯O hydrogen bonding is also present.

Di-μ-chlorido-bis-[(2'-carb-oxybiphen-yl-2-carboxyl-ato-κO)(2,2':6',2''-terpyridine-κN,N',N'')cadmium(II)] hemihydrate

In the centrosymmetric dinuclear title compound, [Cd(2)(C(14)H(9)O(4))(2)Cl(2)(C(15)H(11)N(3))(2)]·0.5H(2)O, each of the Cd(II) ions is coordinated by three N atoms from a chelating 2,2':6',2''-terpyridine ligand, two bridging Cl atoms and one O atom of a 2'-carb-oxy-[1,1'-biphen-yl]-2-carboxyl-ate anion. The coordination environment is distorted octa-hedral. In the crystal, inter-molecular O-H⋯O hydrogen bonds link symmetry-related mol-ecules, forming an infinite chain. The half-occupancy water mol-ecule is disordered over two general sites with 0.25 occupancy and is, in turn, disordered over an inversion center.

Interfacial self-assembly of metal-mediated viologen-like coordination polyelectrolyte hybrids of the bisterpyridine ligand and their optical, electrochemical, and electrochromic properties

Metal-mediated coordination polyelectrolyte multilayers with a bisterpyridine ligand (Bisterpy) have been self-assembled at air-water interfaces via coordination reactions of the bidentate ligand Bisterpy with inorganic salts in the subphases. To avoid dissolution of the viologen-like coordination polyelectrolyte monolayers, anionic poly(styrenesulfonic acid-o-maleic) (PSS) acid was added in the subphases as a supporting layer. The average molecular area of the ligand Bisterpy could reach 1.2-1.5 nm(2) on the surfaces of the subphases containing mixtures of inorganic salts (M) and PSS, although the ligand was unable to form a stable monolayer on the pure water surface. The Langmuir-Blodgett (LB) method was used to deposit the Bisterpy/PSS and M-Bisterpy/PSS hybrid multilayers on the substrate surfaces, which were characterized by using absorption and fluorescence spectroscopy as well as electrochemical analysis. Quasi-reversible redox waves were recorded and centered at about -0.68 and -0.92 V (vs Ag/AgCl), respectively, corresponding to the two-electron process of the ligand, Bisterpy2+ <--> Bisterpy(*+) <--> Bisterpy(0), which were slightly shifted to lower potentials in the LB films of metal-mediated coordination polymers. The film compositions were determined by using X-ray photoelectron spectroscopy. The as-prepared LB films showed strong stability and good electrochromic response upon the applied potential of -1.1 V vs Ag/AgCl and thus could act as potential materials in the development of redox-based molecular switches and display devices.

Synthesis, crystal structure and luminescent properties of one coordination polymer of cadmium(II) with mixed thiocyanate and hexamethylenetetramine ligands

A novel Cd(II) coordination polymer [Cd(SCN)(2)(hmt)(1/2)(H(2)O)](2).H(2)O (hmt=hexamethylenetetramine) has been synthesized and characterized by IR, elemental analysis, TG technique and X-ray crystallography. Cd(II) atom has an distorted octahedral environment with an N(3)S(2)O donor set. Every six Cd(II) centers are linked by hmt and thiocyanato bridges to form a planar 2D coordination polymer containing hexagonal metallocyclic rings [Cd(6)(SCN)(8)(hmt)(2)]. A 2D layer structure is held together with its neighboring ones via a set of hydrogen-bonding interactions to form a 3D supramolecular structure. The luminescent properties of the title complex in the solid state were investigated.

Di-μ-chlorido-bis-[(2,2'-bibenzimidazole)chloridocadmium(II)]

The title binuclear complex, [Cd₂Cl₄(C₁₄H₁₀N₄)₂], was synthesized by the hydro­thermal reaction of CdCl₂ and the ligand 2,2′-bibenzimidazole. The mol­ecule lies on an inversion center and the metal center displays a strongly distorted trigonal-bipyramidal geometry. The Cd^II ions are coordinated by two N atoms from the organic ligand, and by one terminal and two bridging chloride anions. The crystal structure involves inter­molecular N—H⋯Cl hydrogen bonds, resulting in a one-dimensional supra­molecular structure.