Syntheses,crystal structures,and luminescence of two new coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate

Two new coordination polymers, [Zn(H₂btc)(4,4′-bpy)₂] _n (1) and {[Cd(H₂btc) (terpy)]?·?H₂O} _n (2) (H₄btc?=?biphenyl-2,2′,4,4′-tetracarboxylic acid, 4,4′-bpy?=?4,4′-bipyridine, terpy?=?terpyridine), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complexes 1 and 2 are 1-D chains linked through partially deprotonated H₄btc. The adjacent 1-D chains of 1 are further formed into 2-D supramolecular architecture through inter-chain N–H···O hydrogen bonds. In contrast, due to a different auxiliary ligand, the 1-D chains of 2 are further extended into 3-D supramolecular framework through inter-chain O–H···O hydrogen bonds. Thermal stabilities and luminescence of 1 and 2 were also studied.     

Synthesis,crystal structure and properties of two terbium complexes with 2,2′-bipyridine

Two new complexes {[Tb(2-IBA)₃ · 2,2′-bipy]₂ · C₂H₅OH} (1) and [Tb(2-ClBA)₃ · 2,2′-bipy]₂ (2) (2-IBA = 2-iodobenzoate; 2-ClBA = 2-chlorobenzoate; 2,2′-bipy = 2,2′-bipyridine) were prepared and their crystal structures determined by X-ray diffraction. Complex 1 is composed of two types of binuclear molecules, [Tb(2-IBA)₃ · 2,2′-bipy]₂ (a) and [Tb(2-IBA)₃ · 2,2′-bipy]₂ (b), and an uncoordinated ethanol molecule. In molecule (a), two Tb³⁺ ions are linked by four 2-IBA groups, all bidentate-bridging. In molecule (b), two Tb³⁺ ions are held together by four 2-IBA groups in two coordination modes, bidentate-bridging and chelating-bridging. In the two molecules, each Tb³⁺ ion is further bonded to one chelating 2-IBA group and one chelating 2,2′-bipy molecule, resulting in coordination numbers of eight for (a) and nine for (b). The structural characteristics of 2 are similar to that of molecule (b) in 1. The two complexes, 1 and 2, both emit strong green fluorescence under ultraviolet light with the ⁵D₄ → ⁷F _j (j = 6–3) emission of Tb³⁺ ion observed.     

Syntheses,crystal structures,and magnetic properties of two new manganese(II) complexes based on biphenyl-2,5,2′,5′-tetracarboxylic acid

Two new complexes, [Mn(H₂bptc)(2,2′-bpy)₂]?·?2H₂O (1) and [Mn₃(Hbptc)₂(2,2′-bpy)₃(H₂O)₈]?·?2H₂O (2) (H₄bptc?=?biphenyl-2,5,2′,5′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine), have been synthesized under hydrothermal conditions. Their structures have been characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 2 are both linked into 3-D supramolecular networks by non-covalent interactions (O–H?···?O, C–H?···?O, C–H?···?π, and π?···?π). Complexes 1 and 2 exhibit weak antiferromagnetic interactions.     

Synthesis,characterization, and crystal structures of two Ag (I) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate

In this article, [Ag₈(btc)₂(2,2′-bpy)₂] _n (1) and [Ag₄(btc)(phen)₂] _n (2) (H₄btc?=?biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine, phen?=?1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 shows a 3-D framework containing a 2-D bilayer network constructed from (btc)^4? with Ag (I), whereas 2 features a 2-D supramolecular bilayer network. The differences of the two complexes demonstrate that nitrogen-containing chelating ligands have a significant effect on the formation and structure of the resulting complexes. Electrochemistry properties of 1 were also studied.     

Hydrothermal synthesis, crystal structure, and properties of two novel binuclear complexes based on Zaltoprofen and 2,2′-bipyridine ligands

Two novel binuclear metal-organic coordination complexes [M₂(Zaltoprofen)₂(Bipy)₂] [M = Cd (I), Zn (II); Zaltoprofen = 5-(1-carboxyethyl)-2-(phenylthio)phenylacetic acid, Bipy = 2,2′-bipyridine) have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR and electronic spectroscopy, powder X-ray diffraction, and fluorescent properties. Complexes I, II crystallize isomorphously in the monoclinic space group P2₁/c. Structural analysis shows that the M(II) atom of I and II is coordinated with four oxygen atoms from the carboxyl group of the Zaltoprofen together with two nitrogen atoms from the Bipy. The 3D structures of the complexes are stabilized by π-π stacking interactions.     

Crystal structures and properties of two Cu(I) complexes based on Keggin-type clusters and diethyl 4,4′-dicarboxy-2,2′-biquinoline acid

Two proton-conductive Cu(I) complexes based on Keggin-type clusters, [Cu(debqdc)₂]₂[HPW₁₂O₄₀]·4H₂O (1), and [Cu(debqdc)₂]₂[HPW₁₂O₄₀]·debqdc·4H₂O (2), where debqdc is diethyl 4,4′-dicarboxy-2,2′-biquinoline, were simply synthesized at room temperature. The products were structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both complexes crystallized in the triclinic space group P?1 and presented two three-dimensional supramolecular networks with one-dimensional hydrophilic channels via hydrogen-bonding interactions and π–π stacking interactions between the aromatic rings. In the [Cu(debqdc)₂]⁺ ion, debqdc acts as a bidentate nitrogen donor ligand in the chelating fashion. The bulky debqdc ligand constrains the Cu(I) metal center within such a rigid environment in a tetrahedral geometry. The two complexes exhibit good proton conductivities (10^?5 ~ 10^?4 S cm^?1) at 100 °C in the relative humidity range 35 ~ 98%. The luminescence behaviors of these complexes in the solid state at room temperature have also been investigated. Upon excitation at 285 nm, both 1 and 2 display three main emission peaks centered at 470, 520, and 568 nm, respectively.     

Syntheses and characterization of two new compounds based on versatile 1,2,3,5-benzenetetracarboxylic acid and 2,2′-bibenzimidazole

Two coordination complexes based on H₄btec and H₂bibzim (H₄btec = 1,2,3,5-benzenetetracarboxylic acid, H₂bibzim = 2,2′-bibenzimidazole), [Ni(H₂bibzim)₃]₂(btec) (1) and [Zn(H₂bibzim)(btec)_0.5]_n (2), have been synthesized by hydrothermal methods and characterized by single-crystal X-ray diffraction. Complex 1 is composed of [Ni(H₂bibzim)₃]²⁺ with free btec^4? as counter anion. In 2, the btec^4? ligands bridge the Zn(II) ions into a 1-D chain with H₂bibzim as auxiliary chelating ligands. Interesting supramolecular structures were demonstrated due to the existence of hydrogen bonding as well as π?π interactions in the two different complexes. The H₂bibzim ligands act as a 2-connected spacer in both complexes. However, in 1, the [Ni(H₂bibzim)₃]²⁺ cations act as 3-connected nodes, hydrogen bonded with the 6-connected btec^4? ligands into a 3-D framework with (3,6)-connected topology Schläfli symbol as (4.6.8)(4².6)(4³.6⁴.8⁷.10). As for 2, Zn serves as a 3-connected node with btec^4? as a 6-connected node, leading to a 2D (3,6)-connected hydrogen bonding kgd topology sheet with Schläfli symbol of (4³)²(4⁶.6⁶.8³). Thermal stabilities and photoluminescent properties of 1 and 2 were also studied.     

Synthesis,crystal structures and photoluminescence of three new Mn(II) coordination polymers assembled from 2,4′-diphenic acid

Three new metal coordination polymers, [Mn(Hdpa)₂(4,4′-bipy)₂] _n (1), [Mn(dpa)(1,10-phen)(H₂O)] _n (2), and [Mn(dpa)(2,2′-bipy)] _n (3) (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 1,10-phen = 1,10-phenanthroline, and 2,2′-bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. Single-crystal X-ray analyses reveal that 2,4′-diphenic acid is a bridging ligand, exhibiting three coordination modes to link metal ions: μ ₁-η ¹: η ¹/μ ₀-η ⁰: η ⁰; μ ₂-η ²: η ⁰/μ ₁-η ¹: η ⁰; and μ ₂-η ¹: η ¹/μ ₂-η ¹: η ¹. Intermolecular hydrogen bonds in 1 lead to a zigzag chain. In 2, the 2-D supramolecular arrays extended along b-axis through π–π interactions between 1,10-phen. The dinuclear paddle-wheel second building units (SBUs) constructed by four dpa^2? ligands in 3 are linked by dpa^2? into double-strand chains. The fluorescence of H₂dpa and 1–3 are also determined.     

Synthesis,crystal structures and magnetic properties of two new nickel(II) complexes with α-amino acid Schiff base

Two nickel(II) complexes [Ni(napgly)(MeOH)] _n (1) and [Ni(napphe)(H₂O)₂(MeOH)] · H₂O (2), where the tridentate Schiff-base ligands H₂napgly and H₂napphe are condensed from 2-hydroxyl-1-naphthaldehyde with glycine and L-phenylalanine, respectively, were prepared and structurally characterized. In 1, two inversion-related Ni(II) ions were bridged by two O atoms from the phenolate groups of two napgly anions, forming a centrosymmetric dimeric unit which was further linked by carboxylate groups to give a two-dimensional network. Magnetic susceptibility studies performed on the complex revealed anti-ferromagnetic coupling between the metal centers. In 2, the crystal structures of the complex displayed a distorted octahedral coordination geometry in which the ONO-donor Schiff base was bonded to the metal. Intermolecular H-bonds linked the compound into a 2-D layer structure.     

Synthesis and thermal decomposition kinetics of two lanthanide complexes with cinnamic acid and 2,2′-Bipyridine

The two complexes of [Ln(CA)₃bipy]₂ (Ln = Tb and Dy; CA = cinnamate; bipy = 2,2′-bipyridine) were prepared and characterized by elemental analysis, infrared spectra, ultraviolet spectra, thermogravimetry and differential thermogravimetry techniques. The thermal decomposition behaviors of the two complexes under a static air atmosphere can be discussed by thermogravimetry and differential thermogravimetry and infrared spectra techniques. The non-isothermal kinetics was investigated by using a double equal-double steps method, the nonlinear integral isoconversional method and the Starink method. The mechanism functions of the first decomposition step of the two complexes were determined. The thermodynamic parameters (ΔH ^≠ , ΔG ^≠ and ΔS ^≠ ) and kinetic parameters (activation energy E and the pre-exponential factor A) of the two complexes were also calculated.     

pH-dependent syntheses and crystal structures, characterizations, and DFT calculations of complexes with 2,2′-biimidazole and terephthalic acid ligands

The divalent transition metal complexes [Zn(L)₂(H₂O)₂](Tere) (I), [Cd(L)₂(H₂O)₂](Tere]) (II) and [Cd(L)₂(HTere)₂] (III) (L = 2,2’-biimidazole, Tere = terephthalate) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectrum, thermal analysis and single-crystal X-ray diffraction analysis. Complexes II and III have the same starting materials but possess different frame-works and are prepared from H₂Biim and H₂Tere under hydrothermal conditions with different pH values. The crystal structures show I and II have the same coordination circumstances and are coordinated by two H₂O molecules and two neutral bidentate 2,2′-biimidazole ligands. The terephthalate acts as the counter anion. In contrast, complex III contains protonated carboxylate groups coordinated to the metal centre to give neutral species. Furthermore, based on the optimized structures, molecular frontier orbitals, Mulliken charges and IR spetra of complex I and III are investigated by density functional theory. Calculated results show that the energy gap (ΔE _L-H) between HOMO and LUMO of complex III is bigger than that of I. It is revealed that complex III is more stable, and this calculated estimation corresponds with experimental analysis of TGA curves.     

Temperature-dependent synthesis, crystal structures, characterizations, and DFT calculations of two new copper(II) complexes with p-fluorobenzoic acid and 2,2′-bipyridine ligands

Two new copper(II) complexes, [Cu(p-FBA)₂(2,2′-bpy)]·(H₂O) (1) and [Cu(p-FBA)(2,2′-bpy)₂]·(p-FBA)₂ (2) {p-FBA = p-fluorobenzoic acid, 2,2′-bpy = 2,2′-bipyridine} have been obtained from an identical starting mixture using temperature as the only independent variable and characterized by X-ray single crystal diffraction as well as with infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The results reveal that 1 has 1D infinite chain structure formed by O–H···O hydrogen bonds, while 2 features a 0D structure. Additionally, there exist C–H···O hydrogen bonds and π–π stacking interactions in 1, forming 2D supramolecular structure. Furthermore, density functional theory (DFT) calculations of the structures, stabilities, orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the [Cu(p-FBA)₂(2,2′-bpy)] of 1 and [Cu(p-FBA)(2,2′-bpy)₂]⁺ cation of 2 were performed by means of Gaussian 03W package and taking B3LYP/lanl2dz basis set.     

Syntheses,crystal structures and fluorescent properties of two 4,4′-dipyridylsulfide based zinc(II) and cadmium(II) helical complexes

Two allomeric helical coordination polymers, {[Zn(4,4′-dps)₂(HSSA)(H₂O)₂] · 3(H₂O)} _n (1) and {[Cd(4,4′-dps)₂(HSSA)(H₂O)₂] · 3(H₂O)} _n (2) (4,4′-dps = 4,4′-dipyridylsulfide, H₃SSA = 5-sulfosalicylic acid), have been synthesized by similar experimental methods and characterized by elemental analysis, single-crystal X-ray diffraction, and fluorescence spectra. Both crystallize in monoclinic system, space group P₂1/n, with a = 11.7947(13) Å, b = 13.7475(15) Å, c = 20.183(2) Å, and Z = 4 for 1 and a = 11.940(7) Å, b = 14.068(8) Å, c = 20.323(12) Å, and Z = 4 for 2. In both complexes, the metal (Zn^II for 1 and Cd^II for 2) are six-coordinate with a N₃O₃ donor set in a distorted octahedron. Half of the 4,4′-dps are μ ₂-bridging, linking adjacent metal centers and forming P₂1/n dimensional helical structures along the b-axis. Fluorescence measurements show that 1 and 2 have medium fluorescent emission at 402 and 405 nm, respectively.     

Syntheses,crystal structures,and characterization of three metal–organic complexes with 2,2′-biphenyldicarboxylic acid and phenanthroline ligands

Three complexes constructed with 2,2′-biphenyldicarboxylic acid, multidentate nitrogen donors, and metal salts, {[Cd(2,2′-dpdc)(tppp)(H₂O)]₂?·?2H₂O} _n (1), {[Pb(2,2′-dpdc)(pyphen)]₂} _n (2), and {[Pb(2,2′-dpdc)(dppz)]} _n (3) (H₂dpdc = 2,2′-diphenyldicarboxylic acid; tppp = 4-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)phenol; pyphen?=?pyrazino[2,3-f]-[1,10]phenanthroline; and dppz = dipyrido[3,2-a:2′,3′-c]phenazine), are synthesized under hydrothermal conditions. These complexes are characterized by single-crystal X-ray diffraction, elemental analysis, IR, TGA, and photoluminescence. In 1, two 2,2′-dpdc ions bridge two Cd(II) ions to form an isolated cluster with Cd?···?Cd distance of 5.023(4)?Å. These clusters are further linked by intermolecular hydrogen bonds, yielding a 2-D supramolecular structure. Complex 2 contains two crystallographically independent Pb(II) ions in the asymmetric unit. Pb1 ions are bridged by 2,2′-dpdc anions to form a chain along the x-axis. Two Pb2 ions are coordinated by two 2,2′-dpdc anions and two pyphen ligands to form a cluster. These clusters are linked by π–π interactions to yield a 1-D supramolecular chain along the y-axis. In 3, neighboring Pb(II) atoms are bridged by 2,2′-dpdc anions to form a 1-D chain structure. Further, the chains are linked into a 3-D supramolecular network through aromatic π–π interactions.     

Syntheses,crystal structures and photochemistry of two new organic–inorganic hybrid compounds based on copper–glycin complexes and paradodecatungstates

Two organic–inorganic hybrid materials built from copper–glycin complexes and paradodecatungstates, Na₆[{Cu(gly)(H₂O)}]₂[{Cu(H₂O)}(H₂W₁₂O₄₂)] ? 21H₂O (1) and Na{Na(H₂O)₆}{Na(H₂O)₄}₃[{Cu(gly)₂}]₂{H₅(H₂W₁₂O₄₂)} ? 8.5H₂O (gly = glycin) (2), have been synthesized in aqueous solution and characterized by IR, UV, TG, elemental analysis, electrochemistry, and single-crystal X-ray analyses. In 1, [H₂W₁₂O₄₂]^10? building block connects two neighboring clusters with [Cu(H₂O)]²⁺ groups to produce an infinite 1-D chain; then these chains are linked through [Cu(gly)(H₂O)]⁺ groups to form a 2-D layer structure, which is further joined by Na⁺ to form a 3-D network. In 2, [H₂W₁₂O₄₂]^10? decorated by two [Cu(gly)₂] moieties connects four adjacent clusters with six Na⁺ into a 2-D layer. In addition, luminescence and photocatalysis properties of these compounds have been investigated.     

Synthesis and crystal structures of two new Zn(II) coordination polymers with 4,4′-dipyridyl disulfide and dicarboxylate acid

The title compounds, Zn(C₅H₆O₄)(Dpds) · 5H₂O (I) and Zn(C₆H₈O₄)(Dpds) (II) (C₅H₈O₄ = glutaric acid, Dpds = 4,4??-dipyridyl disulfide, and C₆H₁₀O₄ = adipic acid), are two-dimensional metal-organic coordination polymers. In I, the tetrahedra coordinated Zn atoms are bridged by glutarate anions and Dpds ligand to form a 2D layer parallel to (001) plane, which are connected by the 1D water tape notated as T4(2)₅(2) to build up 3D supramolecular architecture. In II, both Dpds ligands and adipate anions act as bidentate bridges, connecting the Zn(II) centers in a tetrahedral coordination geometry into a two-dimensional (4,4) layer. Each layer polycatenates adjacent layers, exhibiting the rare combination of 2D ?? 2D parallels interpenetration.     

Syntheses,crystal structures,and photoluminescent properties of two new Cd(II) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate and dipyridyl-containing ligands

Two new Cd(II) coordination polymers, [Cd₂(btc)(dpe)_1.5(H₂O)]_n (1) and [Cd₂(btc)(bpp)(H₂O)]_n (2), were prepared by the hydrothermal reaction of cadmium nitrate with H₄btc (H₄btc = biphenyl-2,2′,4,4′-tetracarboxylic acid) in the presence of 1,2-di(4-pyridyl)ethylene (dpe) and = 1,2-bis(4-pyridyl)propane (bpp), respectively, structurally characterized by single-crystal X-ray diffraction, and further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. In 1, btc^4? connect six Cd²⁺ ions, forming a 3-D (3,3,6)-connected [Cd₂(btc)] net, and further connected by 1-D [Cd(dpe)]_n chains to construct the final (4,5,6)-connected (4².5².6⁵.7)(4³.6².7)(4⁵.5³.6⁴.7².8) net. In 2, a 3-D [Cd₂(btc)] net is also constructed from btc^4? connecting six Cd²⁺ ions, giving a 3-D (3,4,7)-connected network. The overall structure of 2 can be regarded as a (4,4,6)-connected (4⁵.6⁴) (4².5.6².8) (4³.5⁴.6⁷.7) framework with bpp linking adjacent Cd ions. Structural comparisons show that the secondary auxiliary N-donors have important effects on the final structure and properties. Photoluminescent properties of 1 and 2 are also discussed.     

Syntheses,crystal structures,and fluorescent properties of two Cd(II) complexes based on 2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid)

Two new complexes, [Cd₂(H₄ebidc)₂(CH₃OH)₄]?·?2CH₃OH (1) and {[Cd(Cl)(I)(H₆ebidc)_1/2]?·?1/2bbe?·?H₂O} _n (2) (H₆ebidc?=?2,2′-(ethane-1,2-diyl)bis(1H-imidazole-4,5-dicarboxylic acid), bbe?=?1,2-bis(2-benzimidazolyl)ethane), are obtained through self-assembly of H₆ebidc with Cd(II). Single-crystal X-ray diffraction shows that 1 has a binuclear structure and each tridentate chelating ligand coordinates to two Cd(II) ions with µ₂-O. Complex 2 displays a 1-D chain structure and each tetradentate ligand bridges two Cd(II) ions in chelating fashion. Fluorescent properties have also been determined.     

Synthesis,crystal structures and characterization of iron(III) and cobalt(III) complexes bearing 2,2′-bipyridylcarboxylate ligands

Transition Metal Chemistry - The Fe(III) complex [FeIII(bpdc)(Hbpdc)] (1) (bpdc?=?2,2′-bipyridyl-6,6′-dicarboxylate and...     

Synthesis,structures, thermal behaviour,luminescence and magnetic properties of lanthanide complexes constructed from 2,6-dimethylbenzoic acid and 5,5′-dimethyl-2,2′-bipyridine

Six new lanthanide complexes, with the formula [La(2,6-DMBA)₃(5,5′-DM-2,2′-bipy)(H₂O)]₂ (1) and [Ln(2,6-DMBA)₃(5,5′-DM-2,2′-bipy)]₂ (Ln = Tb(2), Dy(3), Ho(4), Pr(5), Nd(6)) (2,6-DMBA = 2,6-dimethylbenzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′-bipyridine) have been successfully synthesized and characterized. These title complexes have three different structural types. The structure of complex 1(type I) contains coordination water molecules, and the coordination number is 8. The coordination numbers of complexes 2–4 and 5–6 are 8 and 9, showing a distorted square antiprism geometry and distorted monocapped square anti-prismatic geometry, respectively. However they have the same general formula and they can be all assembled into the same 1D, 2D supramolecular structures via the C-H···O hydrogen bonding interactions, which is interesting in previous lanthanide complexes. The complexes were analyzed by TG-DSC/FTIR. In addition, the visible light luminescence experiments of Tb (III) complex was carried out, and the characteristic luminescence behavior of strong green color was shown. And the fluorescence lifetime and intrinsic quantum yield were calculated. The magnetic properties of complexes 2–4 were also studied, and the results showed that complex 3 and complexes 2, 4 have ferromagnetic interactions and antiferromagnetic interactions, respectively.