One-dimensional Double-stranded Chain Research Articles

Crystal Structure and Magnetic Property of 2-(Imidazo[1,2-a]pyri-din-2-yl)-2-oxoacetic Acid and Its Perchlorate

We herein report two crystals based on 2-(imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical and its perchlorate, and investigate the relationship between magnetic properties and crystal stacking structures or supramolecular interactions. 2-(Imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical in two crystals mainly exist as diamagnetic dimer formed via short atomic contacts or supramolecular interactions (hydrogen bonds, anion-π or lone-pair-π interactions), leading to low magnetic susceptibilities. 2-(Imidazo[1,2-a]pyridin-2-yl)-2-oxoacetic acid radical crystal exhibits quasi-one-dimensional columnar stacking chain and weak antiferromagnetism. However, its perchlorate crystal possesses one-dimensional double-stranded chain structure assembled through double hydrogen bonds and anion-π interactions, and reveals weak ferromagnetism.

Two new d10 metal-directed coordination polymers based on an unsymmetrical ligand 3-pyrimidin-5-ylbenzoic acid

Two novel d 10 metal coordination polymers [Cd(3,5-PMBC) 2 (H 2 O) 2 ] ( 1 ) and {[Zn(3,5-PMBC) 2 (H 2 O) 2 ]⋅2H 2 O} ( 2 ) (3,5-PMBC = 3-pyrimidin-5-ylbenzoic acid) have been synthesized under solvothermal conditions, and characterized by IR spectroscopy, powder and single crystal X-ray diffractions. In 1 and 2 , the d 10 metal ions (Zn 2+ and Cd 2+ ) directed the self-assemblies to form two types of significantly different coordination structures: 1 exhibits one-dimensional double-stranded chain, while 2 displays a unique two-dimensional undulated double layer. Both are further stacked via hydrogen-bond interactions to assemble three-dimensional supramolecular structures. Thermal and photoluminescent properties of 1 and 2 are also investigated in details. Two novel d 10 metal-directed coordination polymers [Cd(3,5-PMBC) 2 (H 2 O) 2 ] ( 1 ) and {[Zn(3,5-PMBC) 2 (H 2 O) 2 ]2H 2 O} ( 2 ) have been prepared and characterized. compound 1 exhibits one-dimensional double-stranded chain, while 2 displays an unique two-dimensional undulated double layer. Both are further stacked via hydrogen-bond interactions to form three dimensional supramolecular structures. ► Coordination polymers based on the unsymmetric ligand 3-pyrimidin-5-ylbenzoic acid are not reported so far. ► The first two novel d 10 metal coordination polymers [Cd(3,5-PMBC) 2 (H 2 O) 2 ] ( 1 ) and {[Zn(3,5-PMBC) 2 (H 2 O) 2 ]2H 2 O} ( 2 ) (3,5-PMBC = 3-pyrimidin-5-ylbenzolate) have been synthesized and structurally characterized. ► The strong fluorescence emissions for 1 and 2 have been observed in the solid state.

Synthesis and Characterization of New Coordination Polymers with Tunable Luminescent Properties Generated from Bent 1,2,4-Triazole-Bridged N,N′-Dioxides and Ln(III) Salts

A new bent 1,2,4-triazole-bridged N,N'-dioxide ligand, namely, 3,5-bis(3-pyridyl-N-oxide)-4-amino-1,2,4-triazole (L2), was designed and synthesized by the oxidation of 3,5-bis(3-pyridyl)-4-amino-1,2,4-triazole with H(2)O(2) in the presence of HOAc at ambient temperatures. Eleven Ln(III)-based coordination polymers have been successfully prepared by the solution reactions of L2 with various Ln(III)-perchlorates. The structures of these new Ln(III) polymers clearly reflect the effect of the lanthanide contraction. Compounds 1-6 feature a two-dimensional net, in which the Ln(III) atoms adopt a nine-coordinate {LnO(9)} sphere due to their larger ionic radii, whereas the Ln(III) centers in the one-dimensional double-stranded chains of 7-11 with smaller ionic radii lie in a {LnO(8)} coordination environment. In addition, the tunable emission intensity was realized on 7 by controlling the type of the involved counterion on the basis of a reversible solid-state anion exchange. Such reversible solid-state anion exchange might provide an alternative approach to tuning the luminescence.

Structures of metal-organic networks based on flexible 1,1′-(1,4-butanediyl)bis(imidazole-2-phenyl) ligand

A new neutral ligand 1,1′-(1,4-butanediyl)bis(imidazole-2-phenyl) (bbip) and six coordination polymers, namely [Zn(o-bdc)(bbip)]·H2O (1), [Zn(m-bdc)(bbip)]·H2O (2), [Cd(m-bdc)(bbip)] (3), [Zn(OH–bdc)(bbip)] (4), [Cd(OH–bdc)(bbip)] (5) and [Zn(fum)(bbip)]·H2O (6) (where o-H2bdc = 1,2-benzenedicarboxylic acid, m-H2bdc = 1,3-benzenedicarboxylic acid, OH–H2bdc = 5-hyroxyisophthalic acid and H2fum = fumaric acid), are described. Compound 1 shows a one-dimensional double-stranded chain structure. Compounds 2 and 4 possess 2D polymeric layers, and the layers are connected through van der Waals forces and hydrogen bonds into 3D supramolecular structures, respectively. Compounds 3, 5 and 6 exhibit 3-fold interpenetrating diamondoid networks. The luminescent properties for these compounds in the solid state are discussed.

Catena-Poly[[cobalt(II)-μ-[N,N′-1,3-bis(imidazol-1-ylmethyl)benzene]-κ2 N 3:N 3′-μ-(5-carboxybenzene-1,3-dicarboxylato)-κ2 O 1:O 3] monohydrate

The title CoII coordination polymer, {[Co(C9H4O6)(C14H14N4)]·H2O} n , was obtained by reaction of Co(NO3)2·6H2O, benzene-1,3,5-tricarboxylic acid (H3BTC) and 1,3-bis(imidazol-1-ylmethyl)benzene (L). Each CoII cation is four-coordinated by an O2N2 donor set in a distorted tetrahedral geometry. The CoII centers are connected into a one-dimensional double-stranded chain by HBTC anions and L ligands. The chains are further connected through hydrogen-bonding interactions between the hydroxyl groups of adjacent HBTC anions and face-to-face π–π interactions between the benzene rings of adjacent L ligands [average face-to-face distance of 3.427 (3) Å], resulting in the formation of a three-dimensional supramolecular structure.

5-(4-Methoxyphenyl)-1-(4-methylphenyl)-1H-pyrazol-3-ol

The asymmetric unit of the title compound, C17H16N2O2, contains two crystallographically independent mol­ecules, with methyl­phenyl and methoxy­phenyl substituents in different orientations with respect to the pyrazole ring. In the crystal structure, inter­molecular O—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules; the O—H⋯N bonds generate centrosymmetric dimers, and these are connected by C—H⋯O bonds to generate one-dimensional double-stranded chains.

Syntheses, crystal structures and magnetic properties of three copper(II) coordination polymers with the flexible ligand 1,2-bis(1,2,4-triazol-1-yl)ethane or 1,2-bis(imidazol-1-yl)ethane

In order to investigate the influence of the flexibility of the ligand molecules and the coordination counter anions on the architecture of coordination polymers, three new copper(II) coordination polymers [Cu(bte) 2(dca) 2] n (1), [Cu(bte)(NCS) 2] n (2) and [Cu(bim)(NCS) 2] n (3) were synthesized using the flexible five-membered heterocyclic ligands 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), 1,2-bis(imidazol-1-yl)ethane (bim) and the anion ligands dicyanamide (dca) and thiocyanate. They are characterized by elemental analysis, IR, thermogravimetric analysis and X-ray diffraction analysis. The X-ray diffraction analysis shows that complexes 1, 2 and 3 form the one-dimensional double-stranded chain, linear chain and zigzag chain structures, respectively. The magnetic properties for complexes 1, 2 and 3 have also been studied.

3-Hydroxy-5-(4-methoxyphenyl)-1-phenyl-1H-pyrazole

In the title compound, C16H14N2O2, the two crystallographically independent mol­ecules in the asymmetric unit have different orientations of the phenyl and methoxy­phenyl substituents with respect to the pyrazole ring. Both independent mol­ecules exist as O—H⋯N hydrogen-bonded dimers, which are interlinked via C—H⋯N hydrogen bonds to form one-dimensional double-stranded chains. A three-dimensional network is formed via C—H⋯π interactions.

Syntheses and structures of two one-dimensional double-stranded lead polymers of dicyanamide with unusual coordination mode

The combined use of lead nitrate, sodium dicyanamide (Nadca) and 1,10-phenanthroline or 2,2-bipyridine has led to the preparation of two one-dimensional coordination polymers Pb(dca)(NO 3)(1,10-phen) ( 1) and Pb(dca) 2(2,2′-bipy)(H 2O) ( 2). X-ray crystallography shows that both 1 and 2 have one-dimensional chains with dca in a novel 1,1,5-μ 3-coordination mode, which results in one-dimensional double-stranded chains. This coordination mode has not been observed in the reported complexes of dca, further indicating the versatility of dca in bonding to metal ions.

Coordination Networks Self-assembled by Transition Metal Salts With 4,4′-oxydianiline (4,4′-oda). Syntheses and Structures of ∞ 1 [Ni(NCS) 2 (4,4′-oda) 2 ], ∞ 2 [Co(NCS) 2 (4,4′-oda) 2 ] and ∞ 2 [M(N 3 )(4,4′-oda) 2 ]NO 3 (M=Cd II or Co II )

Four infinite complexes X 1 [Ni(NCS) 2 (4,4'-oda) 2 ], X 2 [Co(NCS) 2 (4,4'-oda) 2 ] and X 2 [M(N 3 )(4,4'-oda) 2 ]NO 3 [M=Cd II ( 3 ) or Co II ( 4 )] were obtained by reactions 4,4'-oxydianiline (4,4'-oda) with Ni(SCN) 2 , Co(SCN) 2 , Cd(N 3 ) 2 and Co(N 3 ) 2 , respectively which have been structurally established by single-crystal X-ray diffraction. Complex 1 contains one-dimensional double-stranded chains comprising 24-membered Ni 2 (4,4'-oda) 2 macrocycles, each formed by two 4,4'-oda ligands and two octahedral Ni II centers. Complex 2 exhibits two-dimensional non-interpenetrating networks consisting of large 48-membered macrocycles each formed by four 4,4'-oda ligands and four octahedral Co II centers. The crystal structures of 3 and 4 are isomorphous and both contain one-dimensional double-stranded chains comprising 24-membered M 2 (4,4'-oda) 2 macrocycles, which are interlinked by w -1,3-azide groups to generate cationic two-dimensional sheets. These sheets are further connected by hydrogen bonds between the amine groups and nitrate ions to furnish three-dimensional networks. Crystal data: complex 1 crystallizes in the monoclinic space group P 2 1 / c with a =11.990(4) Å, b =9.413(4) Å, c =12.827(4) Å, g =116.32(2), V =1297.6(8) Å 3 and Z =2; complex 2 crystallizes in the orthorhombic space group Pbca with a =9.583(2) Å, b =12.738(3) Å, c =21.039(4) Å, V =2568.2(9) Å 3 and Z =4; complex 3 crystallizes in the monoclinic space group C 2/ c with a =23.036(5) Å, b =5.920(1) Å, c =17.800(4) Å, g = 92.67(3), V =2424.8(9) Å 3 and Z =4; complex 4 crystallizes in the monoclinic space group C 2/ c with a = 22.861(5) Å, b =5.812(1) Å, c =17.720(4) Å, g =93.00(3), V =2351.2(8) Å 3 and Z =4.