Synthesis, spectroscopic and thermal studies of the copper(II) aspartame chloride complex

Aspartame adduct of copper(II) chloride Cu(Asp)₂Cl₂·2H₂O (Asp=aspartame) is synthesized and characterized by elemental analysis, FT IR, UV/vis, ESR spectroscopies, TG, DTG, DTA measurements and molecular mechanics calculations. Aqueous solution of the green solid absorbs strongly at 774 and 367 nm. According to the FT IR spectra, the aspartame moiety coordinates to the copper(II) ion via its carboxylate ends, whereas the ammonium terminal groups give rise to hydrogen bonding network with the water, the chloride ions or neighboring carboxylate groups. The results suggest tetragonally distorted octahedral environment of the copper ions.     

Synthesis,crystal structure and anti-ferromagnetic behavior of a two-dimensional manganese(II) complex with 3,6-dinitro-1,2,4,5,-benzenetetracarboxylate anion as bridging ligand

A two-dimensional complex {[Mn₂(DBT)(DMF)₄]·2H₂O}_n (DBT?=?3,6-dinitro-1,2,4,5- benzenetetracarboxylate anion; DMF?=?N,N-dimethylformamide) has been synthesized and its crystal structure determined by X-ray crystallography. The complex crystallizes in a triclinic system and the space group is P 1 with a?=?9.012(5), b?=?9.196(6), c?=?9.910(6)?Å. In the complex there exist two kinds of coordination environments for Mn(II) ions; each DBT coordinates four Mn(II) ions by its four carboxylate groups and in this way a two-dimensional sheet was constructed. The variable-temperature magnetic susceptibility of the complex was measured in the 5–300?K range and the magnetic data indicate that the magnetic interaction between the bridged manganese(II) ions displays an anti-ferromagnetic coupling.     

Synthesis and crystal structure of a novel tartrate copper(II) two-dimensional coordination polymer: {[Cu2(C4H4O6)2(H2O)2]·4H2O}∞

A new 2D coordination polymer, {[Cu₂(C₄H₄O₆)₂(H₂O)₂]·4H₂O}_∞ has been synthesized by the hydrothermal method and characterized by X-ray single crystal diffraction. Every copper(II) atom adopts a distorted octahedral geometry and coordinates with six oxygen atoms from one water molecule and three tartrate acid ions. The two tartrate acid ions have different coordination modes, one provides four oxygen atoms to coordinate with Cu(II) and another coordinates with all six oxygen atoms. Such a coordination mode generates a two-dimensional coordination polymer. In the solid state, the title compound forms a 3D network structure through hydrogen bonds.     

Crystal Structure and Magnetic Properties of a Hexanuclear Copper(II) Carboxylate

The synthesis and characterisation of the hexanuclear copper(II) carboxylate complex [Cu(O₂CCHPhOC₂H₄OC₂H₄OCH₃)₂]₆ ( 1 ) is described. Single‐crystal X‐ray structure analysis reveals that the copper(II) ions are arranged in a six‐membered ring which adopts a chair‐like conformation. The copper(II) ions are bridged by μ₂‐ and μ₃‐coordinating carboxylates. The magnetic behavior of 1 was measured between 2 and 300 K, revealing at low temperature a weak antiferromagnetic interaction. The χ_M(T) dependency was fitted mathematically with one coupling constant J₁ and a paramagnetic impurity α.     

邻苯二甲酸单甲酯双核铜配合物的强反铁磁性和磁构关联研究

以邻苯二甲酸单甲酯(mMP)为配体合成了一个新的双核铜配位化合物[Cu₂(mMP)₂(H₂O)₂]₂·2H₂O (1), 并通过元素分析、红外光谱和X射线单晶衍射等方法对化合物晶体结构进行了表征. 化合物1通过四羧酸桥联的方式形成了桨轮状双金属笼结构. 每个Cu(II)离子采用四方单锥的五配位构型, 其中四个氧原子来自于四个不同的邻苯二甲酸单甲酯配体, 轴向位置上的氧原子则来自于水分子. 配位水分子和溶剂水分子与配体中未配位的氧原子形成了分子间氢键, 并进一步形成三维网络结构. 磁性数据显示双核铜内为强的反铁磁交换作用, 磁耦合作用常数2J=-324 cm^-1. 通过与相关双核铜化合物的对比, 详细分析了化合物的磁构关联并讨论了羧酸类双核铜中强反铁磁性作用的结构因素. 研究表明, 影响羧酸类双核铜强反铁磁性作用的主要结构因素是配体中桥联双核铜的O－C－O部分的电子结构.     

Synthesis and structural studies of (2 E ,3 E ,6 R ,9 E ,11 E )-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime, ligand and its Mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes

This article describes the synthesis of a new (2E,3E,6R,9E,11E)-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime (H₂hmdm), and its mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). The Cu(H₂hmdm), molecule coordinates to the second copper(II) ion through the oximate oxygens to afford a binuclear structure doubly bridged by the oximate groups in the cis arrangement. In the dinuclear complexes, in which the first Cu^II ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^II ion is ligated with the 1,10-phenanthroline nitrogen atoms. Ligand and its mononuclear copper(II), homo and heterodinuclear copper(II)–nickel(II) complexes of (H₂hmdm) were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r., and mass spectral studies. The data support the proposed structure of H₂hmdm and its complexes.     

One—dimensional Network Constructed by Salicylate and Phenanthroline Ligands with Copper（Ⅱ）

A novel complex,[Cu2(phen)(sal)(Hsal)2]n(1),was synthesized and structurally characterized.The basic dimeric units are hold by sal ligands and extended into 1-D network.The carboxylate grougs of salicylates coordinate to the central ion in three different coordination modes:chelating,bridging and bridging-chelating.In the case of bridging-chelating of the carboxylate group of the salicylate,all three oxygen atoms of salicylate are bidentately coordinated to copper ion,namely,μ4-η^3 binding mode.     

Synthesis,crystal structure and ferro-magnetic interaction of a binuclear copper(II) complex with the 1,4-dinitro-2,3,5,6-tetracarboxylatobenzenic anion as bridging ligand

A binuclear complex [Cu₂(DTB)(DMF)₄(H₂O)]·2DMF (DTB = 1,4-dinitro-2,3,5,6-tetracarboxylatobenzenic anion; DMF = N,N-dimethylformamide) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex Cu ion is located in a distorted square pyramidal environment with two oxygen atoms O(1) and O(3) from two carboxylate groups, another two oxygen atoms O(7) and O(8) from terminal ligands of two DMF molecules, and a fifth coordinated oxygen atom O(9) from the terminal ligand of one H₂O molecule, in which the O(8) atom is situated in the apex of the pyramid. DTB as bridging ligand coordinates two Cu ions through its four carboxylate groups. The variable-temperature magnetic susceptibility of the complex was measured in the 5–300 K range. The magnetic coupling parameter is consistent with a ferromagnetic exchange between the two copper(II) centers and the data fit a binuclear magnetic exchange model based on the Hamiltonian operator ( = -2J₁₂, ₁ = ₂= 1/2), giving the ferromagnetic coupling parameter of 2J = 1.80 cm^{- 1}. This is the first example of a tetracarboxylatobenzenic bridging complex exhibiting ferromagnetic interaction.     

Crystal structure,and thermal and magnetic properties of 2,4-dinitrobenzoatoterbium(III) complex

The Tb(III) complex containing 2,4-dinitrobenzoate (2,4-DNB), Tb(2,4-DNB)₃(H₂O)₂]?·?C₂H₅OH has been synthesized and its crystal structure analyzed by X-ray diffraction methods. The complex crystallizes in the triclinic space group P 1, as a linear polymeric chain in which terbium ions are bridged by carboxylate groups. The eight-coordinate Tb ion with six carboxylate groups and two water molecules forms a slightly distorted square antiprism. Thermal and magnetic properties of the terbium complex were also studied.     

Synthesis,Crystal Structures and Magnetic Properties of Three New Polynuclear Cu(II) Complexes Based on the Methoxybenzoate Isomers

In this paper, self-assembly reactions of copper(II) ions, methoxybenzoate isomers and 2,2′-bipyridine yield two copper-oxygen polynuclear complexes: [Cu₂(bpy)₂(2-C₈H₇O₃)₃]·(2-C₈H₇O₃)·14H₂O 1, [Cu₄(bpy)₄(H₂O)(OH)₄]·4(3-C₈H₇O₃)·17H₂O 2, and a simple mononuclear complex [Cu(bpy)(H₂O)(4-C₈H₇O₃)₂] 3. (bpy = 2,2′-bipyridine, C₈H₇O₃ = methoxybenzoate ion). Single crystal X-ray diffraction analyses reval that compound 1 is a dinuclear copper(II) complex which bridged by three carboxylate groups, and 2 presents a discrete step-like tetra-nuclear copper Cu₄O₄ core. Compound 3 shows a square pyramidal mononuclear geometry. The magnetic susceptibility of complex 1 measured from 2 to 300 K, revealed an antiferromagnetic interaction between the Cu(II) ions. Furthermore, the results about IR spectra and thermal analyses were discussed.     

Synthesis,characterization and structures of copper(II) complexes with amide-based ligands: Unusual formation of a linear trimer and a zig-zag chain and their contrast magnetic behaviour

The present work illustrates the versatile coordination modes of the amide-based ligands towards copper(II) ion. The reaction of the deprotonated form of the ligand, [L¹]²⁻ with CuCl₂ affords a linear trinuclear complex, [Cu₃(L¹)₂(Cl)₂(H₂O)] (1) which has been characterized thoroughly including single crystal structure analysis. The structure of 1 shows that one of the arm of the flexible ligand flips to coordinate second copper(II) centre, resulting in the formation of a trinuclear complex. On the other hand, ligand H₂L² in its deprotonated form reacts with Cu(II) ion to give complex 2 with general formula, [Cu(L²)]_n (2). The crystal structure of the complex 2 shows that each copper is square-pyramidal with 5th coordination coming from the O-atom of the amide group from a neighbouring complex. This results in the generation of an one-dimensional zig-zag chain. The variable temperature magnetic measurements of the complexes, 1 and 2 show that while Cu ions in the former are antiferromagnetically coupled (J = −110.34 cm⁻¹), a weak ferromagnetic interaction (J = +3.08 cm⁻¹) exists in the later. A rationale, based on the orbital overlap from the copper ions and associated ligands, is provided for the observed magnetic coupling between the copper ions.     

Synthesis and characterisation of new copper(II) coordination polymers constructed from pyrazine–tetrazole ligands with the formation of a water cluster

Three novel bis-tetrazole ligands (1–3) containing carboxylate functional groups on the tetrazole rings and a rigid pyrazine linker unit, for the construction of coordination polymers when coordinated to copper(II) ions, were synthesised and structurally characterised. The use of pyrazine as a rigid linker between the two tetrazole units was expected to increase the dimensionality of the solid phase polymeric network of the resulting copper(II)-containing compounds. X-ray structures of the ligands revealed the effect of the substitution position on the tetrazole ring of the ester/carboxylate groups. Higher solid phase dimensionality was successfully achieved as shown by the layered two-dimensional (2-D) coordination structure being formed when the pyrazine bis-tetrazole systems were reacted with copper(II) chloride, although not in the expected manner. There was no interaction between the pyrazine nitrogen atoms and the metal ion. Computational studies showed that this was probably due to the geometry, required by the copper ion, to be involved in the close packing between the layers. The 2-D coordination polymer based on the asymmetric substituted pyrazine bis-tetrazole, [Cu(4)(H₂O)](H₂O)₂, was further connected into a three-dimensional (3-D) coordination network through hydrogen bonding between H₂O molecules. These H₂O molecules were connected as a unique 1-D chain throughout the structure.     

Synthesis,spectral, thermal and structural characterization of {[Cu(H2O)3][Cu(MAL)2] · 2H2O}∞ and [Cu(MAL)(TEA)] · H2O (MAL = malonate and TEA = triethanolamine)

A polymeric malonato-bridged copper(II) complex, {[Cu(H₂O)₃][Cu(MAL)₂]· 2H₂O}, and a mononuclear malonato-copper(II) complex with triethanolamine, [Cu(MAL)(TEA)]·H₂O, have been prepared and characterized by elemental analyses, i.r., u.v.–vis, magnetic measurements and single crystal X-ray diffraction. The polymeric complex consists of one-dimensional chains containing the MAL bridged [Cu(H₂O)₃]²⁺ and [Cu(MAL)₂]^2– ions and each MAL ligand simultaneously exhibits chelating bidentate (at one copper atom) and bridging (at the adjacent copper atom) coordination modes. The intrachain Cu1...Cu2 separation is 4.963 Å and the polymeric complex exhibits antiferromagnetic behaviour. In the mononuclear complex, the copper(II) ion is octahedrally coordinated by one bidentate MAL and one tetradentate neutral TEA ligands. The i.r. spectra and thermal decompositions of both complexes are described.     

Mono- and binuclear copper(II) complexes of saccharin with 2-pyridinepropanol synthesis,spectral, thermal and structural characterization

Mono- and binuclear copper(II) saccharinate (sac) complexes containing 2-pyridinepropanol (pypr) have been prepared and characterized by elemental analyses, i.r., u.v.–vis., magnetic measurements and single crystal X-ray diffraction. The copper(II) ion in trans-[Cu(pypr)₂(sac)₂] has –1 site symmetry and is octahedrally coordinated by two bidentate neutral pypr (N, O) and two sac (O) ligands. The binuclear copper(II) complex, [Cu₂(-pypr)₂(sac)₂], is built up around a centre of symmetry and contains two strongly distorted square–planar coordinated copper(II) ions bridged by two alkoxo groups of the deprotonated pypr ligand, which also coordinates to the copper(II) ions through its nitrogen. In contrast to the mononuclear complex, the sac ligands in the binuclear complex is N-coordinated. The binuclear complex exhibits diamagnetic behaviour. The i.r. spectra and thermal decompositions of both complexes are described.     

Synthesis, characterisation and thermal analysis of copper (II) and chromium (II, III) hydrazine carboxylates

Copper(II) hydrazine carboxylate monohydrate, Cu(N₂H₃COO)₂·H₂O and chromium (II, III) hydrazine carboxylate hydrates, Cu(N₂H₃COO)₂·H₂O and Cu(N₂H₃COO)₂·3H₂O have been prepared and characterised by chemical analysis, IR, visible spectra and magnetic measurements. Thermal analysis of the copper complex yields a mixture of copper metal and copper oxide. Chromium complexes on thermal decomposition yield Cr₂O₃ as residue. Decomposition of chromium(HI) complex under hydrothermal conditions yield CrOOH, a precursor to CrO₂.     

Structure and magnetic properties of a copper(II) compound with syn–anti carboxylato- and linear Cu–Cl–Cu chloro-bridges

The copper(II) polymer Cu(2-qic)Cl (2-qic = quinoline-2-carboxylate) was synthesized and then characterized by X-ray crystal structure determination, spectroscopic and magnetic studies. The crystal structure consists of copper(II) ions with two different chromophores: four-coordinated in a square-planar geometry and five-coordinated in an environment between square-pyramidal and trigonal-bipyramidal. The copper ions are bridged sequentially through the carboxylate groups in a syn–anti conformation, forming an infinite one-dimensional zigzag chain with two alternating non-equivalent copper(II) chromophores. The chloride atom acts as a single chloro-bridge link to adjacent chains, forming a ribbon type structure (1D). The variable-temperature (1.8–300 K) magnetic susceptibility data of the complex were interpreted with the dimer law using the molecular field approximation. The results obtained indicate a very weak ferromagnetic (J₂ = 0.37 cm⁻¹) interchain interaction through the syn–anti carboxylate bridge. A relatively strong antiferromagnetic interaction, transmitted through the chloro-bridge with an exchange coupling of J₁ = −57.0 cm⁻¹, dominates the magnetic properties of this complex. The magnitude and the nature of the exchange coupling are explained on the basis of the structural results.     

Synthesis,Crystal Structure and Magnetism of A 1-D Polymeric Manganese(II) Complex with 2-Hydroxyl-2-Hydroxylate-Malonate as Bridging Ligand

A one-dimensional chain complex {Na[MnL(H₂O)₂]} _n (L = 2-hydroxyl-2-hydroxylate-malonate trivalent anion) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex each Mn ion is located in a distorted octahedral environment with two oxygen atoms O(7) and O(8) from terminal ligands of two H₂O molecules, and four other coordinating oxygen atoms O(1), O(5), O(3A) and O(6A) from two bridging ligands, respectively. Each bridging ligand provides four coordinating oxygen atoms, in which O(6) comes from the hydroxylate, O(5) from the hydroxyl, and O(1) and O(3) from two carboxylate groups, respectively. The O(1) and O(5) atoms coordinate to one Mn ion and the O(3) and O(6) atoms coordinate to another Mn ion; a one-dimensional chain is thereby constructed. The variable-temperature magnetic susceptibility of the complex was measured in the 4–300 K range. The magnetic coupling parameter is consistent with an antiferromagnetic exchange and generates the antiferromagnetic coupling parameter, 2J=–0.0544 cm^–1.     

Synthesis and structural studies of (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}pyridin-2-yl)imino]butan-2-one oxime, ligand and its mono-, di- and trinuclear copper(II) complexes

A new dioxime ligand, (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}-pyridin-2-yl)imino]butan-2-one oxime, (H₂Pymdo) (3) has been synthesized in H₂O by reacting 2,3-butenedione monoxime (2) with 2,6-diaminopyridine. Mono-, di- and tri-nuclear copper(II) complexes of the dioxime ligand (H₂Pymdo) and/or 1,10-phenanthroline have been prepared. The dioxime ligand (H₂Pymdo) and its copper(II) complexes were characterized by ¹H-n.m.r., ¹³C-n.m.r. and elemental analyses, magnetic moments, i.r. and mass spectral studies. The mononuclear copper(II) complex of H₂Pymdo was found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The trinuclear copper(II) complex (6) was formed by coordination of the third Cu(II) ion with dianionic oxygen atoms of each of two molecules of the mononuclear copper(II) complexes. The data support the proposed structure of H₂Pymdo and its Cu(II) complexes.     

Solvothermal synthesis and crystal structures of two new copper(II) terephthalates

Two new copper(II) complexes, [Cu₂(bipy)₂(H₂O)₃(tp)(NO₃)](NO₃) · H₂O (1) and [Cu₂(bipy)₂(tp)₂(H₂O)] _n (2), (tp = terephthalato, bipy = 2,2-bipyridine), have been synthesized and their crystal structures determined by single-crystal X-ray diffraction methods. Complex (1) contains a non-coordinated nitrate anion and an asymmetric binuclear cation in which each copper ion has a distorted square pyramidal coordination geometry with the axial Cu—O distance elongated. The crystal structure of (2) features a zigzag 1D polymeric chain along the diagonal axis of the (0 0 1) plane. Tp adopts two types of coordination mode. In the first mode, both carboxylate groups are unidentate, as in complex (1). In addition to the first mode, the tp ligand in complex (2) also adopts the second coordination mode, in which one carboxylate group is unidentate and the other is bidentately chelating with a copper(II) ion. The magnetic properties of complex (2) have also been studied.     

Thermal and magnetic behaviour of 5-chloro-2-nitrobenzoates of Co(II), Ni(II) and Cu(II)

5-Chloro-2-nitrobenzoates of Co(II), Ni(II) and Cu(II) having formulae Co(C₇H₃O₄NCl)₂·3H₂O, Ni(C₇H₃O₄NCl)₂·3H₂O and Cu(C₇H₃O₄NCl)₂·2H₂O, were obtained as polycrystalline compounds. From the IR spectra analysis of complexes, sodium salt and according to the spectroscopic criteria the carboxylate ions seem bidentate groups. The complexes of Co(II) and Cu(II) lose the water of crystallization in one step at 363–523 K. The Ni(II) complex loses it in two stages in the ranges of 323–378 and 378–523 K, respectively. The compounds follow the Curie–Weiss law. The magnetic moment values experimentally determined change from 4.53 to 4.55 μ_B for Co(II) complex, from 2.34 to 2.97 μ_B for Ni(II) 5-chloro-2-nitrobenzoate and from 1.80 to 1.90 μ_B for Cu(II) complex.