Adjacent CuII Ions Research Articles

Two new 4-coordinate Cu(II) chains with 1,2,3-triazole derivate as bridging ligand: Synthesis, structures and magnetic properties

Two one-dimensional Cu(II) coordination polymers, [Cu(tdp)X2]n (X = Cl(1), Br(2), tdp = 2,2’-(1H-1,2,3-triazole-1,5-diyl)dipyridine) have been synthesized and characterized, which are the first two examples of 1D CuII chains bridging by the rigid 1,2,3-triazole ligand. Compounds 1 and 2 are isomorphous. Single-crystal X-ray diffraction revealed that the ligands bridge adjacent CuII ions into an infinite one-dimensional chain with a zigzag motif in compound 1. Meanwhile, the presence of weak face-to-face π···π interactions between pyridine ring planes of two adjacent chains leads to the stabilization of the molecular packing. DC magnetic susceptibility measurements indicated the presence of weak ferromagnetic interactions (J = 1.91 cm−1 for 1, J = 0.48 cm−1 for 2) between adjacent CuII ions within the chains and antiferromagnetic interchain coupling (J′ = −0.20 cm−1 for 1, J′ = −0.10 cm−1 for 2) due to the π···π interactions.

Preparation and characterization of two new CuII supramolecular coordination polymers incorporating sulfobenzoate and flexible heterocyclic ligands.

The assembly of CuII with the multifunctional ligand 2-amino-4-sulfobenzoic acid (H2asba) in the presence of the auxiliary flexible ligands 1,4-bis(triazol-1-ylmethyl)benzene (bbtz) and 1,4-bis(imidazol-1-ylmethyl)benzene (bix) under ambient conditions resulted in two new supramolecular coordination polymers, namely poly[[(3-amino-4-carboxybenzenesulfonato-κO)aquabis[μ2-1,4-bis(triazol-1-ylmethyl)benzene-κ2N4:N4']copper(II)] 3-amino-4-carboxybenzenesulfonate tetrahydrate], {[Cu(C7H6NO5S)(C12H12N6)2(H2O)](C7H6NO5S)·4H2O}n, (1), and poly[[bis(μ2-2-amino-4-sulfonatobenzoato-κ3O1:N,O1')tetraaqua[μ2-1,4-bis(triazol-1-ylmethyl)benzene-κ2N4:N4']dicopper(II)] tetrahydrate], {[Cu2(C7H5NO5S)2(C14H14N4)(H2O)4]·4H2O}n, (2). Single-crystal X-ray structure diffraction analysis of (1) reveals that the bbtz ligand acts as a bridge, linking adjacent CuII ions into a two-dimensional cationic (4,4) topological network, in which the coordinated 3-amino-4-carboxybenzenesulfonate (Hasba-) anion uses its sulfonate group to bind with the CuII ion in a monodentate fashion and the carboxylate group remains protonated. The lattice Hasba- anion resides in the two-dimensional layer and balances the charge. The carboxylate group of the 2-amino-4-sulfonatobenzoate (asba2-) ligand in (2) is involved in bidentate coordination, connecting adjacent CuII ions into carboxylate-bridged chains which are further bridged by the auxiliary flexible bix ligand in a trans-gauche (TG) mode, resulting in the formation of a two-dimensional network architecture. The amino group of the asba2- ligand in (2) also takes part in the coordination with the central CuII ion. The six-coordinated CuII centres in (1) and (2) exhibit distorted octahedral coordination geometries. Extensive hydrogen bonding exists in both (1) and (2). The interlayer hydrogen bonds in both compounds further extend adjacent two-dimensional layers into three-dimensional supramolecular network architectures. Furthermore, a detailed analysis of the solid-state UV-Vis-NIR (NIR is near IR) diffuse reflectance data indicates that (1) and (2) may have potential as wide band gap indirect semiconductor materials. Compounds (1) and (2) show reversible and irreversible dehydration-rehydration behaviours, respectively.

A two-dimensional copper(II) coordination polymer based on 2,4'-oxybis(benzoate) and 4,4'-bipyridine.

The reaction of Cu(NO3)2·3H2O with 2,4'-oxybis(benzoic acid) and 4,4'-bipyridine under hydrothermal conditions produced a new mixed-ligand two-dimensional copper(II) coordination polymer, namely poly[[(μ-4,4'-bipyridine-κ2N,N')[μ-2,4'-oxybis(benzoato)-κ4O2,O2':O4,O4']copper(II)] monohydrate], {[Cu(C14H8O5)(C10H8N2)]·H2O}n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. The X-ray diffraction crystal structure analysis reveals that the CuII ions are connected to form a two-dimensional wave-like network through 4,4'-bipyridine and 2,4'-oxybis(benzoate) ligands. The two-dimensional layers are expanded into a three-dimensional supramolecular structure through intermolecular O-H...O and C-H...O hydrogen bonds. Furthermore, magnetic susceptibility measurements indicate that the complex shows weak antiferromagnetic interactions between adjacent CuII ions.

Mixed ligand coordination polymer based on 5-nitroisophthalic acid and 1-(4-nitrophenyl)-1,2,4-triazole: Synthesis, characterization, magnetic and photocatalytic properties

A new Cu(II) coordination polymer, namely, [Cu(NPT)2(NO2-BDC)]n (1) (NO2-H2BDC=5-nitro-1,3-benzenedicarboxylic acid, NPT=4-(4-nitrophenyl)-1,2,4-triazole) has been synthesized under hydrothermal condition and characterized by elemental analysis, and single-crystal X-ray diffraction. Single-crystal X-ray diffraction study reveals that complex 1 features one-dimensional chain structure. The magnetic studies reveal that the antiferromagnetic interactions exist between the adjacent CuII ions. Moreover, complex 1 displays highly photocatalytic degradation activity for the degradation of rhodamine B, methylene blue and methyl orange.

A new mixed N-/O-donor for constructing functional CuII-coordination polymer: Crystal structure, photocatalysis and magnetic properties

A first transition–metal coordination polymer [CuH2L(H2O)]n (1) based on a new mixed N-/O-donors 5-[2-carboxy-3-(1H-tetrazol-5-yl)-phenoxy]-isophthalic acid (H4L), which exhibits a 2D 3-connected polymeric network, has been presented and characterized by single-crystal X-ray diffraction, elemental analysis, IR and TGA. It has prominently displayed highly photocatalytic degradation activity for dye degradation as well as antiferromagnetic interactions between the adjacent CuII ions.

Synthesis, crystal structure, and magnetism of a 1-D CuII chain complex with a mono-bromide bridge

A 1-D CuII chain, [Cu(μ-Br)(phenmp)2]n·(ClO4)n (phenmp = 2-(4-methyl-pyrazol-1H-yl)-1,10-phenanthroline), was synthesized and its crystal structure was determined by X-ray crystallography. CuII is located in a distorted square-pyramidal geometry, with the mono-bromide – a bridge linking two adjacent CuII ions with a separation of 3.788 Å. The result is a uniform 1-D chain that lies along the c axis. Mono-halide-bridged models have not been reported very often. The fitting for the data of the variable-temperature (2.00–330 K) magnetic susceptibilities gave a ferromagnetic interaction of J = 5.11 cm−1 (H = −2JS 1 S 2) for adjacent-bridged CuII ions. Comparing mono-halide bridged CuII complexes, trigonal-bipyramidal geometry has strong magnetic interactions, whereas square-pyramidal geometry has weak magnetic interactions. In mono-bromide bridged CuII complexes, the Cu–Br–Cu angle is related to the magnetic coupling signs with small Cu–Br–Cu angle favoring ferromagnetic interaction, while large Cu–Br–Cu angle results in antiferromagnetic interactions.

Syntheses, Structures and Electrochemical Properties of Two New Copper(II) Complexes Based on Isomeric Bis(pyridylformyl)piperazine Ligands and Rigid=Flexible Organic Dicarboxylates

Two new copper(II) complexes, [Cu2(3-bpfp)(2,6-PDA)2(H2O)2] (1) and [Cu(4-bpfp)0:5 (glu)]·H2O (2), have been hydrothermally synthesized by self-assembly of isomeric bis(pyridylformyl)piperazine ligands [3-bpfp=bis(3-pyridylformyl)piperazine, 4-bpfp=bis(4- pyridylformyl)piperazine], rigid pyridine-2,6-dicarboxylic acid (2,6-H2PDA) or flexible glutaric acid (H2glu), and copper(II) chloride. Single-crystal X-ray diffraction analysis reveals that two adjacent CuII ions are connected by the 3-bpfp ligand to build a dinuclear unit in complex 1, in which 2,6-PDA serves as a terminal chelating ligand. Adjacent dinuclear units are further linked by hydrogen bonding and π-π stacking interactions to form a three-dimensional (3D) supramolecular network. Complex 2 is a 3D coordination polymeric framework based on a layer polymer [Cu(glu)]n and bridging 4-bpfp ligands with 6-connected (44.610.8) topology. In 1 and 2, the ligands 3-bpfp and 4-bpfp adopt a μ2-bridging coordination mode (via ligation of pyridyl nitrogen atoms). The thermal stability and the electrochemical properties of the title complexes have been studied.

Supramolecular Isomerism of One‐Dimensional Copper(II) Phosphonate and Its Influence on the Magnetic Properties

AbstractThe reaction of 1‐phosphonomethyl‐2‐benzimidazolpyrrolidine (pmbpH2) and CuCl2 under slightly different conditions has generated three isomers: [Cu(pmbp)]⋅2.5 H2O (1), [Cu(pmbp)]⋅2 H2O (2), and [Cu(pmbp)(H2O)]⋅x H2O (3). All show 1D chain structures in which the adjacent CuII ions are connected purely by the OPO bridges, but the chains are packed in different manners. Dominant antiferromagnetic interactions are observed in these compounds. However, the coupling constant between the metal centers varies significantly for the isomers, which is attributed mainly to the intrachain structural parameters, such as the intrachain Cu⋅⋅⋅Cu distance and the torsion angles over the phosphonate bridge. DFT calculations have been conducted to understand the magnetostructural relationship.

Two Novel 3D Copper Phthalate Coordination Complexes Incorporating Isomeric Flexible Bis(pyridylformyl)piperazine Ligands

AbstractTwo novel metal‐organic coordination complexes [Cu(3‐bpfp)(pht)(H2O)]·2H2O (1) and [Cu3(4‐bpfp)(pht)2(OH)2]·2H2O (2) were hydrothermally synthesized by self‐assembly of phthalic acid (H2pht), flexible bis(pyridylformyl)piperazine ligands [3‐bpfp = bis(3‐pyridylformyl)piperazine, 4‐bpfp = bis(4‐pyridylformyl)piperazine], and copper chloride. Single crystal X‐ray diffraction analysis revealed that the adjacent CuII ions are connected by pht showing different coordination modes [a bis(monodentate) coordination mode for 1 and a monodentate‐bidentate coordination mode for 2] to form 1D Cu‐pht‐Cu chains in 1 and 2D Cu‐pht layers in 2. In compound 1, a twofold interpenetrated CdSO4‐like topology is formed by connection of 3‐bpfp. Using the isomeric ligand 4‐bpfp instead of 3‐bpfp resulted in the formation of 2, which displays a novel 3, 4, 4, 4‐connected tetranodal 3D coordination polymeric framework. The ligand 3‐bpfp adopts a μ2‐bridging coordination mode in 1 (by ligation of the pyridyl nitrogen atoms), whereas the ligand 4‐bpfp adopts a μ4‐bridging coordination mode (by ligation of pyridyl nitrogen and carbonyl oxygen atoms) in 2. Moreover, the electrochemical properties of carbon paste electrodes bulk modified with the two copper complexes were studied.

Synthesis and properties of five unexpected copper complexes with ring-cleavage of 3,6-di-2-pyridyl-1,2,4,5–tetrazine by one pot in situ hydrothermal reaction

Solvothermal reactions of CuSO4·6H2O and Cu(Ac)2·H2O with 3,6-di-2-pyridyl-1,2,4,5-tetrazine (DPTZ) in the presence of different acetonitrile/water ratios (from 1:3 to 3:1) and temperatures (from 40 to 120 °C) successfully produce five coordination polymers: [Cu4(SO4)2(H2O)5(L2)2] (1), [Cu2SO4(H2O)3(L2)] (2), [Cu2(μ-CN)2(L1)] (3), [Cu2(bdc0.5)2(L2)(H2O)] (4, H2bdc = p-phthalic acid) and [Cu(L3)2] (5) (the known mononuclear compound). Unexpectedly three ligands: 2,5-bis(2-pyridyl)-1,3,4-oxodiazole (L1), N-bis-(R-hydroxyl-2-pyridyl)ketazine (H2L2) and pyridine-2-carboxylate (HL3), were obtained through NN bond cleavage of DPTZ. Complexes 1, 2 and 3 own one-dimensional (1D) structures, complex 4 shows a two-dimensional (2D) framework. The new compounds were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. We focus our study on the ring-opening reaction mechanism, the occurrence process of CuII → CuI, the C–CN cleavage reaction of acetonitrile under lower temperatures (40–60 °C) and the influence of temperature and the ratio of solvent. In addition, magnetic susceptibility measurements indicate that 1, 2 and 4 show strong antiferromagnetic interactions between the adjacent CuII ions.

A Doubly End-On Azido-Bridged Trinuclear Cu(II) Complex: Synthesis, Spectral and DFT Functional Studies

A trinuclear, doubly azido-bridged Cu(II) complex, [Cu1.50(L)(N3)3(CH3OH)]2, (LH = [(CH3)2NCH2CH2N=CHC6H3(OH) (OMe)]), has been synthesised and fully characterised by elemental analyses, IR, UV-Vis, EPR and DFT studies. Its single crystal X-ray structure reveals that adjacent CuII ions are linked by double end-on azido-bridges; thus the full molecule is generated by the site symmetry of a crystallographic two-fold rotation axis.

Synthesis of Two New Linear Trinuclear CuII Complexes: Mechanism of Magnetic Coupling through Hybrid B3LYP Functional and CShM Studies

Two new Cu(II) linear trinuclear Schiff base complexes, [Cu3(L)2(CH3COO)2] (1) and [Cu3(L)2(CF3COO)2] (2), have been prepared using a symmetrical Schiff base ligand H2L [where H2L = N,N'-bis(2-hydroxyacetophenone)propylenediimine]. Both of the complexes have been characterized by elemental analyses, Fourier transform IR, UV/vis, and electron paramagnetic resonance spectroscopy. Single-crystal X-ray structures show that the adjacent Cu(II) ions are linked by double phenoxo bridges and a mu(2)-eta(1):eta(1) carboxylato bridge. In each complex, the central copper atom is located in an inversion center with distorted octahedral coordination geometry, while the terminal copper atoms have square-pyramidal geometry. Cryomagnetic susceptibility measurements over a wide range of temperature exhibit a distinct antiferromagnetic interaction of J = -36.5 and -72.3 cm(-1) for 1 and 2, respectively. Density functional theory calculations (B3LYP functional) and continuous-shape measurement (CShM) studies have been performed on the trinuclear unit to provide a qualitative theoretical interpretation of the antiferromagnetic behavior shown by the complexes.

Catena-Poly[[{2-[3-(dimethylamino)propyliminomethyl]-4-nitrophenolato}copper(II)]-μ-acetato

The title compound, [Cu(C12H16N3O3)(CH3COO)]n or [Cu(CMP)(CH3COO)]n {CMP is 2-[3-(dimethyl­amino)propyl­imino­meth­yl]-4-nitro­phenol}, was synthesized by the reaction of 2-hydr­oxy-5-nitro­benzaldehyde, N,N-dimethyl­propane-1,3-diamine and copper(II) acetate monohydrate in a methanol solution. The compound is an acetate-bridged polymeric copper(II) complex. The CuII atom is coordinated in a square-pyramidal manner by one Schiff base CMP ligand and two acetate anions. The Schiff base mol­ecule acts as a tridentate ligand, coordinating the CuII ion through its phenolate O atom, imine N atom and amine N atom. The acetate anion acts as a bridging group, coordinating two adjacent CuII ions through its two O atoms, one in the basal plane and the other in the apical position. The [Cu(CMP)] units are linked through the bridging acetate groups, forming chains running along the c axis.

Catena-Poly[[[aqua(2-amino-4,6-dimethylpyrimidine-κN1)copper(II)]-μ-benzene-1,3-dicarboxylato-κ2O1:O3] 2-amino-4,6-dimethylpyrimidine solvate

In the title polymer, {[Cu(C8H4O4)(C6H9N3)(H2O)]·C6H9N3}n, the CuII ion approximates a distorted square-pyramidal geometry defined by an NO4 donor set. Adjacent CuII ions are bridged by isophthalate dianions to form a one-dimensional chain. Chains inter­act through π–π stacking inter­actions of 2-amino-4,6-dimethyl­pyrimidine rings and hydrogen bonds, to build a three-dimensional crystal structure.

The co-crystal tetraaquabis(2-oxido-3,5-dinitrobenzoato)bis(2-oxido-3,5-dinitrobenzoic acid)tricopper–diaquabis(2-hydroxy-3,5-dinitrobenzoato)(2-oxido-3,5-dinitrobenzoic acid)copper–water (0.54/0.92/4): a reformulation?

In the title compound, [Cu3(C7H3N2O7)2(C7H2N2O7)2(H2O)4]0.54[Cu(C7H3N2O7)2(H2O)2]0.92·4H2O, the CuII ion located on an inversion centre has a fractional site occupancy of 0.54. When this CuII ion is present, a trinuclear complex also involving two adjacent CuII ions arises; when it is not, then the result is two discrete mononuclear complexes. A very similar structure was reported previously by Valigura, Melnık, Koman, Martiŝka, Korabik, Mroziński & Glowiak [Inorg. Chem. Commun. (2004), 7, 548–552]. However, in their material, arising from a different synthesis, the CuII ion with \overline{1} site symmetry is fully occupied, and thus only a trinuclear complex is formed. Here, the mononuclear CuII complex assumes a square-pyramidal coordination geometry, formed by two water mol­ecules and two 3,5-dinitro­salicylate anions, one of which is monodentate and the other bidentate.

Catena-poly[aqua(2,2'-bipyridine)copper(II)-μ-benzene-1,4-dioxyacetato

In the title coordination polymer, [Cu(1,4-BDOA)(2,2′-bipy)(H2O)]n (where 1,4-BDOA2− is benzene-1,4-dioxy­acetate, C10H8O6, and 2,2′-bipy is 2,2′-bipyridine, C10H8N2), each CuII atom is six-coordinate and displays a distorted square-pyramidal geometry, with the basal plane capped by one very long semicoordinate Cu—O bond of 2.920 (3) A. Adjacent CuII ions are bridged by carboxyl­ate groups, resulting in a one-dimensional chain structure with a shortest Cu⋯Cu distance of 13.484 (3) A. Furthermore, these chains are linked through hydrogen bonds and π–π stacking inter­actions to form a supramolecular network.

Structural and Magnetic Characterization of a Linear Trinuclear Copper Complex Formed through Ligand Sharing

AbstractReaction of bis(2‐hydroxybenzyl)‐1,3‐diamino‐2‐propanol (H2bhbdp) with copper perchlorate in methanol leads to the assembly of a trinuclear complex with the general formula [Cu3(bhbdp)2(CH3OH)2(ClO4)2] (1). The complex was characterized by X‐ray crystallography, Ligand Field, IR and ESR spectroscopy, and magnetic susceptibility. The structure of the complex contains a linear trinuclear array of copper ions [the Cu(1)−Cu(2)−Cu(1a) angle is 180° by symmetry], in octahedral, square planar and octahedral environments, respectively. The external Cu1 and Cu1a centers are coordinated by two amine nitrogens, two phenolate oxygen donors, one methoxide oxygen and one oxygen from a perchlorate, while the central Cu2 is coordinated by four phenolate oxygens through ligand sharing. A strong antiferromagnetic interaction between the adjacent CuII ions dominates the magnetic properties of 1 leading to an S = 1/2 ground state which is fully populated below 150 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

One-dimensional magnetism and crystal structure ofcatena-di-bromobis(3,5-dimethylpyridine)copper(II)

Crystals of catena-di-??-bromobis(3,5-dimethylpyridine)copper(II) are monoclinic, space group P21/a. The unit cell constants are a=13.900(2), b=14.416(2), c=4.097(1) ??, ??=93.49(2)??, V=819.4 ??3 and Z=2. The structure was determined from powder data using a Guinier-Johansson focussing powder camera. The structure was solved using a simplex method for function minimization to a conventional R-value of 0.13. The structure consists of infinite linear chains parallel to c in which the copper coordination is distorted elongated octahedral. Cu-Br distances were found to be 2.449(7) and 3.286(7) ??, whereas the Cu-N bond length is 2.02(2) ??. All distances are in the range usually observed for this type of compounds. The antiferromagnetic superexchange interactions between adjacent CuII ions (J = -21 cm-1) has been compared with those observed in structural similar CuBr2L2 compounds. The differences in observed J-values are discussed briefly, in relation to the structural variations. It appears that very small changes in structural parameters strongly affect the magnetic exchange. ?? 1979 Verlag Chemie, GmbH.