Synthesis,characterization, and properties of copper and manganese complexes with 5-(benzimidazol-1-ylmethyl)isophthalate

Four new complexes, [Cu(L)] (1), [Cu₂(L)(dpe)_0.5]?·?2.5H₂O (2), [Mn(L)] (3), and [Mn(L)(pybim)] (4) [H₂L?=?5-(benzimidazol-1-ylmethyl)isophthalic acid, dpe?=?1,2-di(pyridin-4-yl)ethylene, pybim?=?2-(pyridin-2-yl)-1H-benzimidazole], have been synthesized under hydrothermal conditions and characterized by single-crystal and powder X-ray diffractions, FT-IR, and elemental analysis. The crystal structural analyses reveal that 1 and 4 are uninodal 3-connected 2-fold interpenetrated 2-D networks with (6³) topology, 2 shows an infinite 1-D double-stranded chain structure, and 3 exhibits a uninodal 4-connected 2-D network with (4⁴?·?6²) topology. The factors influencing the structures of the coordination polymers are discussed. In addition, the thermal stabilities of 1–4, second-order non-linear optical effect of 1, and preliminary magnetic property of 3 have also been investigated.     

Ligand-directed assembly of distinct 1-D CdII coordination polymers with a bent dipyridyl derivative and two isophthalates bearing different 5-substituents

Two 1-D Cd^II coordination polymers, {[Cd(4-abpt)(hip)(H₂O)₂](H₂O)_7/2} _n (1) and {[Cd(4-Habpt)(sip)(H₂O)](H₂O)₂} _n (2) (4-abpt?=?4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole, H₂hip?=?5-hydroxyisophthalic acid, H₃sip?=?5-sulfoisophthalic acid), have been hydrothermally synthesized and structurally characterized. Complex 1 has a comb-like 1-D coordination chain, while 2 presents a 1-D dual-track motif. The structural modulation of the coordination polymers can be achieved by simply changing the 5-substituent of the isophthalate from a hydroxyl group to a sulfonate group. Further, supramolecular architectures with higher dimensionality are constructed via hydrogen bonding and/or aromatic π-stacking interactions. Both complexes have been characterized by IR, microanalysis, and powder X-ray diffraction techniques. In addition, the solid fluorescence properties of both complexes have also been investigated.     

A new luminescent 3-D metal-organic framework of diamond-like network possessing 8-fold interpenetration

A new 3-D coordination polymer [Zn(L)₂] (1) (HL?=?4-(pyridin-4-ylmethoxy)benzolic acid) was synthesized under hydrothermal conditions with Zn(OAc)₂?·?2H₂O and HL and characterized by single crystal X-ray diffraction (XRD). Compound 1 displays a 3-D 8-fold interpenetrating structure with diamondoid framework containing large adamantanoid cages. Meanwhile, it exhibits intense fluorescence at 402?nm in the solid state. In addition, powder XRD and thermogravimetric (TG) analysis for 1 are also reported.     

Three copper(II) complexes of 4-formylbenzoate obtained from degradation of the Schiff base

A 1-D copper(II) coordination polymer and two mononuclear copper(II) complexes of 4-formylbenzoate, [Cu(L)₂(H₂O)₂] _n (1), [Cu(L)₂(D,L-cam)] (2), and [Cu(L)(bpy)₂]?·?(ClO₄)(H₂O) (3) (HL?=?4-formylbenzoic acid, D,L-cam?=?D,L-camphoric diamine, bpy?=?2,2′-bipyridine), have been obtained from cleavage of C=N double bonds of a bis-Schiff-base compound. 4-Formylbenzoate exhibits bidentate chelating and bidentate μ ₂-bridging modes by terminal carboxylic and aldehydic groups in 1-D coordination polymer 1. In contrast, it shows bidentate chelating in 2 and monodentate and bidentate bonding in 3 by its terminal carboxylic group where the aldehydic group does not coordinate. Offset π–π stacking interactions and two types of 8-membered hydrogen-bonding rings are found between neighboring molecules of the copper(II) complexes.     

Two cobalt coordination polymers based on an asymmetric dicarboxylate: structural diversity tuned by auxiliary ligands

Two 1-D cobalt coordination polymers, [Co(mbtx)(hpht)(H₂O)] _n (1) and [Co(mbix)(hpht)] _n (2) (mbtx?=?1,3-bis(1,2,4-triazol-1-ylmethyl)benzene, mbix?=?1,3-bis(imidazol-1-ylmethyl)benzene, H₂hpht?=?homophthalic acid), were synthesized by hydrothermal reactions and characterized by elemental analyzes, IR spectroscopy, thermogravimetry, and single-crystal X-ray diffraction. Complex 1 is a 1-D heterostranded double-helical chain as a result of bridging hpht and mbtx, and the 1-D chains are further self-assembled into a 2-D layer structure through hydrogen bonds. Complex 2 shows a 1-D molecular ladder structure, linked through C–H···π interactions to give a 2-D layer structure, which is further linked through C–H?O hydrogen bonds to form a 3-D framework. The mbtx adopts cis-conformation in 1, while for 2, mbix has trans-conformation. Factors causing the differences between 1 and 2 are discussed.     

Synthesis,structure, and properties of a coordination polymer based on N- and O-donors

A ternary coordination polymer, [Cd(L)(pbda)_0.5] _n [HL?=?3,5-bis(2-pyridylmethyl)aminobenzoic acid, pbda?=?dianion of 1,4-benzenedicarboxylic acid], has been synthesized and characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction analysis. The single-crystal X-ray crystallography reveals that the complex is a 2-D wave-like network. The cadmium has an unsymmetrical seven-coordinate [CdN₂O₅] geometry, coordinated by two nitrogens and five oxygens from L^? and pbda. Hydrogen bonds between the uncoordinated (2-pyridylmethyl)amino groups from adjacent layers form dimers across the inversion center, superposing different layers to construct a 3-D framework. To the best of our knowledge, [Cd(L)(pbda)_0.5] _n represents the first example of a complex containing 3,5-bis(2-pyridylmethyl)aminobenzoate.     

Preparation,characterization, and properties of a Ag(I) coordination polymer {[Ag(H3bptc)(bpe)] · 2H2O} n

A new coordination polymer, {[Ag(H₃bptc)(bpe)]?·?2H₂O} _n (1) (H₄bptc?=?3,3′,4,4′-benzophenonetetracarboxylic acid, bpe?=?1,2-bis(4-pyridyl)ethene), has been synthesized through a hydrothermal technique and structurally characterized. The crystal structure of 1 exhibits a 2-D hydrogen-bonding sheet between H₃bptc^? and two free water molecules. Fluorescent property, TG analysis, and X-ray powder diffraction for 1 were also measured and discussed.     

Hydrothermal synthesis,crystal structures,and photoluminescent properties of two cadmium(II) coordination polymers derived from dicarboxylates and N-donor ligands

Two metal coordination polymers, [Cd(ipa)(L₁)(H₂O)]_n (1) and [Cd(ipa)(L₂)]_n (2) [H₂ipa?=?isophthalic acid, L₁?=?3,5-bis(imidazole-1-yl)pyridine and L₂?=?3,5-bis(benzoimidazo-1-ly)pyridine], have been synthesized and structurally characterized by IR, elemental analysis, XRD, and X-ray single-crystal diffraction. Complex 1 shows a twofold cds topological net and 2 features a 3-D pcu topological net. Luminescent properties of 1 and 2 were investigated in the solid state at room temperature.     

Crystal structure and characterization of two cadmium(II) coordination polymers with a multidentate N-donor tecton 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole

Two new cadmium(II) complexes [Cd_1.5(L)Cl₂(H₂O)]_{2 n} (1) and [CdL₂] _n (2) with a multidentate N-donor building block 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (HL) have been prepared and characterized by elemental analysis, infra-red spectra, powder X-ray diffraction (XRD), and single-crystal XRD. 1 is a 2-D layered coordination polymer constructed from linkage of [Cd₃(μ-Cl)₄] trinuclear units with HL spacers, while 2 shows a 2-D layer structure. 3-D supramolecular architectures are further assembled in 1 and 2 via hydrogen-bonding contacts. Both 1 and 2 are thermally stable to 450?°C, and 2 showed strong fluorescent emission bands.     

Two copper(II) metal–organic networks derived from bis-pyridyl-bis-amide ligands and aromatic polycarboxylates: a 2-D layered structure and a 4-connected trinodal 3-D topology

Two metal–organic coordination polymers, [Cu₃(4-bpcb)₂(1,2,4-btc)₂(H₂O)₂] (1) and [Cu₃(3-bpcb)₃(btec)_1.5] (2), have been synthesized from hydrothermal reaction of copper chloride with mixed ligands [4-bpcb?=?N,N′-bis(4-pyridinecarboxamide)-1,4-benzene, 3-bpcb?=?N,N′-bis(3-pyridinecarboxamide)-1,4-benzene, 1,2,4-H₃btc?=?1,2,4-benzenetricarboxylic acid, and H₄btec?=?1,2,4,5-benzenetetracarboxylic acid]. X-ray diffraction analysis reveals that 1 exhibits a 2-D layer structure and 2 possesses a three-dimensional (3-D) network. In 1 and 2, Cu^II ions are connected by bridging 1,2,4-btc or btec to form 2-D polymeric layers. Cu-1,2,4-btc layer does not propagate into a 3-D coordination framework in 1 due to 4-bpcb showing monodentate coordination (via ligation of only one pyridyl nitrogen). In 2, Cu-btec 2-D layers are further extended into a 3-D network with (6⁴.8²)₃ topology by 3-bpcb ligand in μ ₂-bridging coordination (via ligation of two pyridyl nitrogens). The different structures of the two complexes illustrate the influence of different polycarboxylates and N-donor positions of organic ligands on the formation of such coordination architectures. Moreover, the thermal properties and electrochemical properties of the copper complexes bulk-modified carbon paste electrodes have been studied.     

Isothiocyanate and selenocyanate complexes of Cu(II), Ni(II), and Co(II) with a pyridylpyrazole-based ligand: synthesis,characterization, and structure

Mononuclear NCS^? containing complexes, [M(NCS)₂L] (L?=?N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)aminomethylpyridine), [Cu(NCS)₂L′] (L′?=?N-(3,5-dimethylpyrazol-1-ylmethyl)aminomethylpyridine), and NCSe^? containing complexes [ML(NCSe)(H₂O)]ClO₄ (M?=?Ni⁺², Co⁺²) have been synthesized and characterized by elemental analysis, spectroscopic, and physico-chemical methods. Structural studies of [Cu(NCS)₂L′] show copper is five coordinate with distorted trigonal bipyramidal geometry with two cis NCS^?. [M(NCS)₂L] and [ML(NCSe)(H₂O)]ClO₄ (M?=?Ni⁺² and Co⁺²) are expected to be octahedral.     

Lanthanide-based coordination polymers assembled from derivatives of 3,5-dihydroxy benzoates: syntheses, crystal structures, and photophysical properties

Two new aromatic carboxylic acids, namely, 3,5-bis(benzyloxy)benzoic acid (HL1) and 3,5-bis(pyridine-2-ylmethoxy)benzoic acid (HL2), have been prepared by replacing the hydroxyl hydrogens of 3,5-dihydroxy benzoic acid with benzyl and pyridyl moieties, respectively. The anions derived from HL1 and HL2 have been used for the support of a series of lanthanide coordination compounds [Eu(3+) = 1-2; Tb(3+) = 3-4; Gd(3+) = 5-6]. The new lanthanide complexes have been characterized on the basis of a variety of spectroscopic techniques in conjunction with an assessment of their photophysical properties. Lanthanide complexes 2, 4, and 6, which were synthesized from 3,5-bis(pyridine-2-ylmethoxy)benzoic acid, were structurally authenticated by single-crystal X-ray diffraction. All three complexes were found to exist as infinite one-dimensional (1-D) coordination polymers with the general formula {[Ln(L2)(3)(H(2)O)(2)]·xH(2)O}(n). Scrutiny of the packing diagrams for 2, 4, and 6 revealed the existence of interesting two-dimensional molecular arrays held together by intermolecular hydrogen-bonding interactions. Furthermore, the coordinated benzoate ligands serve as efficient light harvesting chromophores. In the cases of 1-4, the lowest energy maxima fall in the range 280-340 nm [molar absorption coefficient (ε) = (0.39-1.01) × 10(4) M(-1) cm(-1)]. Moreover, the Tb(3+) complexes 3 and 4 exhibit bright green luminescence efficiencies in the solid state (Φ(overall) = 60% for 3; 27% for 4) and possess longer excited state lifetimes than the other complexes (τ = 1.16 ms for 3; 1.38 ms for 4). In contrast to the foregoing, the Eu(3+) complexes 1 and 2 feature poor luminescence efficiencies.     

Copper(I) and copper(II) complexes with pyrazine-containing pyridylalkylamide ligands N-(pyridin-2-ylmethyl)pyrazine-2-carboxamide and N-(2-(pyridin-2-yl)ethyl)pyrazine-2-carboxamide

Four copper(II) complexes and one copper(I) complex with pyridine-containing pyridylalkylamide ligands N-(pyridin-2-ylmethyl)pyrazine-2-carboxamide (HL^pz) and N-(2-(pyridin-2-yl)ethyl)pyrazine-2-carboxamide (HL^pz?) were synthesized and characterized. The X-ray crystal structures of [Cu₂(L^pz)₂(4,4?-bipy)(OTf)₂] (1, OTf?=?trifluoromethanesulfonate, 4,4?-bipy?=?4,4?-bipyridine) and [Cu(L^pz)(py)₂]OTf·H₂O (2, py?=?pyridine) revealed binuclear and mononuclear molecular species, respectively, while [Cu(L^pz)(μ₂-1,1-N₃)]_n (3), [Cu(L^pz?)(μ₂-1,3-N₃)]_n (4), and [Cu(HL^pz)Cl]_n (5) are coordination polymer 1-D chains in the solid state.     

Four Zn(II)/Cd(II) coordination polymers derived from isomeric benzenedicarboxylates and 1,6-bis(triazol)hexane ligand: synthesis,crystal structure,and luminescent properties

Four coordination polymers, [Zn(o-bdc)(bth)_0.5(H₂O)] _n (1), [Cd(o-bdc)(bth)_0.5(H₂O)] _n (2), [Zn(m-bdc)(bth)] _n (3), and [Cd(p-bdc)(bth)?·?(H₂O)₂] _n (4) (where o-bdc?=?1,2-benzenedicarboxylate, m-bdc?=?1,3-benzenedicarboxylate, p-bdc?=?1,4-benzenedicarboxylate, and bth?=?1,6-bis(triazol)hexane), have been hydrothermally synthesized and structurally characterized. Both 1 and 2 are isostructural, featuring two binodal architectures: (6³)(6⁵·8) topology in terms of o-bdc and Zn^II/Cd^II as three- and four-connected nodes. Complex 3 shows a 2-D (4,4) network with the Zn?···?Zn?···?Zn angle of 57.84°, whereas 4 exhibits planar 2-D (4,4) network. These 2-D networks of 3 and 4 are extended by supramolecular interactions, such as CH?···?π/π–π stacking and hydrogen-bonding into 3-D architecture. A structural comparison of these complexes demonstrates that the dicarboxylate building blocks with different dispositions of the carboxyl site play a key role in governing the coordination motifs as well as 3-D supramolecular lattices. Solid-state properties such as photoluminescence and thermal stabilities of 1–4 have also been studied.     

Syntheses,structures, and properties of CdII and CoII complexes with 5-(pyridin-4-yl)isophthalate

A N-donor containing carboxylic ligand, 5-(pyridin-4-yl)isophthalic acid (H₂L), was applied to construct two new coordination polymers [Cd(L)(DMF)] _n (1, DMF?=?N,N-dimethylformamide) and {[Co(L)(H₂O)₂]?·?0.5CH₃OH?·?1.5H₂O} _n (2) under different conditions. The complexes were characterized by IR, elemental, and thermogravimetric analyses, powder and single crystal X-ray diffraction. In 1 each L^2? links four Cd^II to form a 3-D framework, while in 2 each L^2? connects three metals to form a 2-D layer structure, which is further connected together by hydrogen bonds to form a 3-D architecture. The thermal stability of the complexes and the photoluminescence of 1 were investigated.     

Synthesis and structures of 4,5-dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride and 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole)

4,5-Dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride (1) was synthesized and characterized by IR and NMR spectroscopy and X-ray diffraction. An attempt to prepare the free tridentate N-heterocyclic carbene pincer ligand by the reaction of 1 with KN(SiMe₃)₂ resulted in the formation of 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole) as a product of dimerization of the target carbene followed by the rearrangement accompanied by the elimination of dipyridylethane.

     

Three double- or triple-stranded chains constructed from different cobalt(II) salts and a flexible bis-triazole ligand

Three coordination compounds, {[Co(btrp)₂(H₂O)₂]?·?NO₃?·?H₂O} _n (1), {[Co(btrp)₂(H₂O)₂]?·?H₂O?·?2H₂btc} _n (2), and {[Co(btrp)₃]?·?2ClO₄} _n (3) (btrp?=?1,3-bis(1,2,4-triazol-1-yl)propane; H₃btc?=?benzene-1,3,5-tricarboxylic acid), have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction and elemental analyses. Compound 1 possesses a 1-D double-stranded chain composed of ribbons of 20-membered cycles. Binuclear water clusters link adjacent nitrate anions to form a 1-D supramolecular helix in the structure. Compound 2 has a 1-D double-stranded chain wherein free H₂btc ligands constitute 1-D negative chains through classical hydrogen-bonding interactions (O–H?···?O). Compound 3 exhibits a triple-stranded 1-D chain. For 1–3, 3-D supramolecular structures are consolidated by interchain weak hydrogen-bonding interactions as well as electrostatic interactions.     

Two new metal-organic frameworks possessing binodal high-connected topologies based on Cd4-clusters and organic ligands

Two new compounds, [Cd₂(bptc)(bpimb)(H₂O)]?·?2H₂O (1) and [Cd₂(bptc)(bpib)]?·?4H₂O (2) (where H₄bptc?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, bpimb?=?1,3-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)benzene, bpib?=?1,4-bis(2-(pyridin-2-yl)-1H-imidazol-1-yl)butane), were synthesized by reactions of the corresponding metal salts with H₄bptc and N-containing auxiliary ligands and their structures have been determined by single-crystal X-ray diffraction. Compound 1 is built by Cd₄-clusters which further construct a 3-D (3,8)-connected framework with tfz-d notation; 2, also built by Cd₄-clusters, is a 3-D (4,8)-connected framework with (3²?·?4²?·?5²)(3⁴?·?4⁸?·?5¹²?·?6⁴) topology. In addition, the elemental analyses, infrared spectra, fluorescence, and thermogravimetric analyses for 1 and 2 are discussed.     

Seven-, eight-, and ten-coordinated cerium(III) with highly connective pyridine-2,4,6-tricarboxylate,oxalate, and glycine ligands

Two new 3-D Ce(III) coordination polymers, [Ce_1.3(PTA)₂(Oxa)₂(Gly)(H₂O)₂]·(Gly)4H₂O (1) and [Ce_2.6(PTA)₄(Oxa)₂(H₂O)₁₀]·(MeOH)7H₂O (2) (PTA?=?2,4,6-pyridinetricarboxylate, oxa?=?oxalate and Gly?=?glycine), were synthesized. The oxalate in 1 and 2, generated in situ from the cleavage and chemical rearrangement of PTAH₃, assembled into mixed-ligand networks to generate 3-D frameworks. Single crystal analysis reveals that in both complexes, Ce(III) shows coordination numbers of 7 and 10 in 1 and 8 and 10 in 2. PTA adopts four kinds of coordination modes. These complexes were further characterized using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.     

Syntheses,structures, and fluorescent properties of four Co(II) coordination polymers based on 5-hydroxyisophthalic acid and structurally related bis(benzimidazole) ligands

Four cobalt(II) coordination polymers, {[Co(HO-BDC)(bbp)]}_n (1), {[Co(HO-BDC)(bmbp)₂]·(H₂O)₂}_n (2), {[Co(HO-BDC)(bbb)]}_n (3), and {[Co₂(HO-BDC)₂(bmbb)₂]·(H₂O)₃}_n (4), where HO-H₂BDC?=?5-hydroxyisophthalic acid, bbp = 1,3-bis(benzimidazol-1-yl)propane, bmbp = 1,3-bis(2-methyl-benzimidazol-1-yl)propane, bbb = 1,4-bis(benzimidazol-1-yl)butane, and bmbb = 1,4-bis(2-methyl-benzimidazol-1-yl)butane, have been synthesized and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, thermogravimetric analyses, and fluorescence properties. Compounds 1 and 3 are 4-connected 2-D networks with (4⁴·6²) topology. Compound 2 is a 1-D chain, while 4 features a 1-D ladder. These 1-D and 2-D complexes are further connected by hydrogen bonds to form 3-D supramolecular architectures. Complexes 1–4 showed very strong yellow luminescence emission.