Copper(II) complexes with bis(4-iodo-3,5-dimethylpyrazol-1-yl)methane: Synthesis,spectroscopic study,and crystal structure

New complexes of copper(II) nitrate, chloride, tetrafluoroborate, perchlorate, and perrhenate with bis(4-iodo-3,5-dimethylpyrazol-1-yl)methane (L) were obtained. The molecular and crystal structures of [CuL(H₂O)(NO₃)₂] · (CH₃)₂CO, [CuL₂(H₂O)][CuL₂Cl][CuCl₄], [CuL₂](BF₄)₂ · (CH₃)₂CO, and [CuL₂(H₂O)](ClO₄)₂ · (CH₃)₂CO were determined by X-ray diffraction analysis. In all the complexes, L was found to serve as a chelating bidentate ligand through the N² and N^2′ atoms of its pyrazole rings to form a six-membered chelate ring.     

Cu(II), Cd(II) and Ni(II) azide complexes incorporating bis(3,5-dimethylpyrazol-1-yl)methane - Synthesis, spectroscopic characterisation, X-ray studies and magnetic properties

Three novel compounds [Cu₂(μ_1,1-N₃)₂(N₃)₂(bdmpzm)₂] (1) [Cd(N₃)₂(bdmpzm)]_n (2) and [Ni(N₃)₂(bdmpzm)₂] (3) have been synthesised and characterised structurally and spectroscopically. The structure 1 consists of a neutral dinuclear [Cu₂(μ_1,1-N₃)₂(N₃)₂(bdmpzm)₂] entities, compound 2 has one-dimensional zigzag chain structure extending along the crystallographic direction [1 0 0] with alternating di-μ_1,1-N₃ and di-μ_1,3-N₃ bridges, and 3 is a mononuclear complex. The experimental studies on the nickel(II) complex have been accompanied computationally by the density functional theory (DFT) calculations.     

Synthesis,crystal structure and physicochemical properties of copper(II) complexes containing bis[(benzimidazol-2-yl)methyl] ether derivatives

A new benzimidazoyl ligand bis[(N-ethylbenzimidazol-2-yl)methyl]ether (EDGB) and Cu^II complexes [Cu(L¹) (L²)](ClO₄)·mEt₂O·nH₂O [L¹ = bis[(benzimidazol-2-yl)methyl]ether (DGB) or EDGB, L² = 2,2-bipyridine (bipy) or 1,10-phenanthroline (phen)] have been synthesized and characterized by elemental analyses and i.r. spectra. The single-crystal structure of the [Cu(phen)(DGB)(OClO₃)]ClO₄·Et₂O·0.5H₂O complex was determined by X-ray diffraction. The geometry around Cu is best described as a distorted octahedron with four nitrogen atoms from phen and DGB ligands forming the equatorial plane. The oxygen atoms of DGB and one perchlorate group are in the axial positions with semi-coordinated bonding modes. The electrochemical behavior of the complexes is described.     

Synthesis, crystal structure, and magnetic properties of oxime-bridged polynuclear Ni(II) and Cu(II) complexes

Two new polynuclear complexes [Ni6(amox)6(mu6-O)(mu3-OH)2](Cl2).6H2O and [Cu3(amox)3(mu3-OH)(mu3-Cl)](ClO4).4H2O (amox- = anion of 4-amino-4-methyl-2-pentanone oxime) have been synthesized and characterized structurally and magnetically. The Ni(II) complex contains a novel Chinese-lantern-like Ni6 cage centered by an oxo ion. It contains the nearest octahedral Ni(II)...Ni(II) separation (<2.8 A) and exhibits strong antiferromagnetic properties. The Cu(II) complex has a cyclic trinuclear copper(II) core bridged by both mu3-OH(-) and mu3-Cl(-) ions. The magnetic susceptibilities of both antiferromagnetic complexes were fitted by using approximate models.     

Heterobimetallic oxalato-bridged Cu(II)Re(IV) complexes. Synthesis, crystal structure and magnetic properties

Three copper(II)-rhenium(IV) bimetallic complexes of formula [ReCl(4)(mu-ox)Cu(phen)(2)] (1), [ReCl(4)(mu-ox)Cu(phen)(2)].CH(3)CN (2), and [ReCl(4)(mu-ox)Cu(terpy) (H(2)O)][ReCl(4)(mu-ox)Cu(terpy)(CH(3)CN)] (3) (ox = oxalate anion, phen = 1,10-phenanthroline, and terpy = 2,2':6,2"- terpyridine) have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the triclinic system, space group P(-1), with a = 9.776(2), b = 11.744(3), c = 14.183(3) A, alpha =102.09(2) degrees, beta = 109.42(2) degrees, gamma = 107.11(2) degrees, and Z = 2, whereas 2 and 3 crystallize in the monoclinic system, space groups P2(1)/n and P2(1)/c, respectively, with a = 12.837(3), b = 17.761(4), c = 12.914(3) A, beta = 91.32(2) degrees, and Z = 4 for 2, and a = 8.930(2), b = 18.543(4), c = 27.503(6) A, beta = 94.67(2) degrees, and Z = 4 for 3. The structures of 1 and 2 are made up of neutral [ReCl(4)(mu-ox)Cu(phen)(2)] bimetallic units. Re(IV) and Cu(II) metal ions exhibit distorted octahedral coordination geometries, being bridged by a bis(bidentate) oxalato ligand. The presence of acetonitrile molecules of crystallization in 2 causes a somewhat greater separation between the bimetallic complexes and a different packing of these units in the crystal structure with respect to 1. The copper-rhenium separation across oxalato is 5.628(2) in 1 and 5.649(3) A in 2. The structure of 3 is made up of two different and neutral bimetallic units, [ReCl(4)(mu-ox)Cu(terpy)(H(2)O)] and [ReCl(4)(mu-ox)Cu(terpy)(CH(3)CN)]. In the first one, the oxalate group behaves as a bis(bidentate) ligand occupying one equatorial and one axial position in the elongated octahedral environment of Cu(II). The water molecule is axially coordinated. In the second one, the oxalate group behaves as a bidentate/monodentate ligand occupying the axial position in the square pyramidal environment of Cu(II). The acetonitrile molecule occupies a basal coordination position around the copper atom. These units are arranged in such a way that a chlorine atom of the first unit (Cl(1)) points toward the copper atom (Cu(2))of the second one (3.077(2) A for Cl(1)(.)Cu(2)), forming a tetranuclear species. The copper-rhenium separation across bis(didentate) oxalato is 5.504(3) A, whereas that through bidentate/monodentate oxalato is 5.436(2) A. The magnetic behavior of 2 and 3 has been investigated over the temperature range 1.8-300 K. A very weak and nearly identical antiferromagnetic coupling between Re(IV) and Cu(II) through bis(bidentate) oxalato occurs in 2 (J = -0.90 cm(-1)) and 3 (J = -0.83 cm(-1)); it is ferromagnetic in 3 through both the bidentate-monodentate oxalato (J = +5.60 cm(-1)) and the chloro (J = +0.70 cm(-1)) bridges.     

Tricarbonyl rhenium complexes of bis(pyrazol-1-yl)methane and bis(3,5-dimethylpyrazol-1-yl)methane – Synthesis,spectroscopic characterization,X-ray structure and DFT calculations

Two novel tricarbonyl rhenium complexes based on the bidentate heterocyclic N–N ligands [bis(pyrazol-1-yl)methane(bpzm) and bis(3,5-dimethylpyrazol-1-yl)methane(bdmpzm)] have been synthesized by heating at reflux [Re(CO)₅Cl] with the appropriate N–N ligand in toluene. The compounds have been characterized by IR and UV–Vis spectroscopy and X-ray analysis. Density functional theory (DFT) and time-dependent (TD) DFT calculations have been carried out for the [Re(CO)₃(bdmpzm)Cl] complex.     

Copper(II) complexes of bis(pyrazol-1-yl)methane - Synthesis, spectroscopic characterization, X-ray structure and DFT calculations

Two novel copper(II) complexes incorporating bis(pyrazol-1-yl)methane ligand (bpzm) have been synthesized. The compounds [CuCl(bpzm)₂(H₂O)]Cl·H₂O (1) and [Cu(N₃)₂(bpzm)]_n (2) have been studied by IR, UV-Vis spectroscopy and X-ray crystallography. The experimental studies on the compounds 1 and 2 have been accompanied computationally by the density functional theory (DFT) calculations.     

Synthesis and structure of a complex of copper(II) bromide with bis(benzotriazol-1-yl)methane

The preparation technique of a complex of copper(II) bromide with bis(benzotriazol-1-yl)methane (L), (Cu₂L₂Br₄)_n, is developed. The compound is studied by single crystal and powder X-ray diffraction and static magnetic susceptibility techniques. According to single crystal XRD data, the complex has a layered structure determined by bidentate bridging coordination of L with N(3) and N(3′) atoms to copper(II). The elementary unit of {Cu₂(μ-Br)₂Br₂} polymer has a binuclear structure. The coordination polyhedron is a trigonal pyramid, and the coordination core is CuN₂Br₃. The temperature dependence of effective magnetic moment is studied within an interval of 2–300 K. The nature of the μ_eff(T) dependence indicates that antiferromagnetic exchange interactions dominate in exchange clusters of the complex with an even number of paramagnetic centers. Original Russian Text Copyright ? 2007 by E. V. Lider, A. S. Potapov, E. V. Peresypkina, A. I. Smolentsev, V. N. Ikorskii, A. I. Khlebnikov, and L. G. Lavrenova __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No.3, pp.543–547, May–June, 2007.     

Synthesis,crystal structure and magnetic properties of a new 1-D oxamidate-bridged Cu(II)-Mn(II) polymer

A new coordination polymer, {[Cu(aeop)Mn(H₂O)₃]₂}_n (H₄aeop = N′-(2-aminoterephthalic acid)-N′′-(1,3-propanediamine)oxamidate), has been synthesized and characterized structurally and magnetically. This complex features a 1-D ladder-like chain structure constructed from neutral tetranuclear units through the syn-anti carboxylate bridges. This crystal forms in the triclinic system, space group P 1, with a = 9.653(1) Å, b = 9.686(1) Å, c = 10.903(1) Å, α = 80.984(1)°, β = 69.776(1)°, γ = 80.729(1)° and z = 2. The relationship between its magnetic properties and structure has also been investigated.     

A new molecular building blocks: Synthesis,crystal structure,magnetic and spectroscopic properties of Cu(II) and Ni(II) macrocyclic complexes

New higly unsaturated macrocyclic building blocks [CuLSCN]·ClO₄ (1) (L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) and [NiL(SCN)₂] (2) (L = N-dl-5,12-dimethyl-7,14-diisopropyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) were synthesized and the crystal structures of both compounds were determined. Both complexes crystallizes in monoclinic, space group P2₁/n (1) and P2₁/c (2). Their magnetic properties were studied over the temperature range 1.8–300 K using a Quantum Design SQUID magnetometer (MPMSXL-5-type). The results indicate that both compounds behave as weakly interacting paramagnetic centers in the crystal lattice. The effects of hydrogen bond mediating the magnetic exchange interactions on the spin density have been evidenced by DFT calculations. The NIR–Vis–UV diffuse-reflectance electronic spectra confirm the square pyramidal and octahedral geometry around Cu²⁺ and Ni²⁺ metal ions.     

Synthesis, structure, and magnetic properties of two 1-D helical coordination polymeric Cu(II) complexes

Two helical coordination polymeric copper(II) complexes bearing amino acid Schiff bases HL or HL′, which are condensed from 2-hydroxy-1-naphthaldehyde with 2-aminobenzoic acid or l-valine, respectively, have been prepared and characterised by X-ray crystallography. In [CuL]_n (1) the copper(II) atoms are bridged by syn-anti carboxylate groups giving infinite 1-D right-handed helical chains which are further connected by weak C-H?Cu interactions to build a 2-D network. While in [CuL′]_n (2) the carboxylate group acts as a rare monatomic bridge to connect the adjacent copper(II) atoms leading to the formation of a left-handed helical chain. Magnetic susceptibility measurements indicate that 1 exhibits weak ferromagnetic interactions whereas an antiferromagnetic coupling is established for 2. The magnetic behavior can be satisfactorily explained on the basis of the structural data.     

Supramolecular self-assembly of two Cu(II) complexes with 1,2,4-triazole derivatives: syntheses,crystal structures and magnetic properties

Two two-dimensional coordination complexes, {[Cu₄(BTM)₆(OPA)₄] · 4DMF · 3H₂O} _n (1) and {[Cu(BDTM)(OH)](ClO₄) · 2H₂O} _n (2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4-triazol-1-yl)methane, OPA²⁻ = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal geometry in 1, in which OPA²⁻ ligands bridge Cu²⁺ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer structure. In 2, each Cu²⁺ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands. Two hydroxyl groups bridge two Cu²⁺ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with large channels along a axis. Magnetic properties revealed that both OPA²⁻ and OH⁻ mediate anti-ferromagnetic interactions between Cu²⁺ ions with J = − 0.06(3) and −301.9(2) cm⁻¹ for 1 and 2, respectively. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,crystal structure,and magnetic properties of a linear trinuclear Cu(II) complex

A new linear trinuclear Cu(II) complex, [Cu₃(NTA)₂(4,4′-bpt)₄(H₂O)₂]?·?10H₂O (H₃NTA?=?nitrilotriacetic acid, 4,4′-bpt?=?4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole) (1), was obtained from evaporation of an aqueous solution containing Cu(NO₃)₂?·?6H₂O, 4,4′-bpt, nitrilotriacetic acid (H₃NTA), and NaOH. 1 was characterized using single-crystal X-ray diffraction, IR, and elemental analysis. In the trimer, the three linear copper ions are bridged by two NTA carboxylate groups in a syn–anti conformation and connected by 4,4′-bpt to produce a 1-D array. Temperature-dependent magnetic susceptibilities reveal the presence of weak antiferromagnetic exchange between metal centers.     

New tetranuclear Cu(II) complexes: synthesis, structure, and magnetic properties

The synthesis, structure, and magnetic properties of two new tetranuclear Cu(II) complexes containing N,N,N',N'-tetraethylpyridine-2,6-dithiocarboxamide (S-dept) of formula [Cu(2)Cl(2)(mu-S-dept)(2)][Cu(2)Cl(4)(mu-Cl)(2)] (1) and [Cu(2)(mu-Cl)(2)(S-dept)(2)][CuCl(3)(EtOH)](2) (2) are reported. Their X-ray crystal structures reveal that the complexes are composed of anionic and cationic dimers, that in both cases contain the metal centers which interact via Coulombic and/or hydrogen bonding interactions. In both cases, the Cu centers in the anionic moieties adopt a slightly distorted tetrahedral geometry whereas for the cationic moieties they adopt a square-pyramidal type of geometry. Magnetic susceptibility data show that compounds 1 and 2 present an overall antiferromagnetic behavior arising from the contribution of both anionic and cationic moieties. For 1, the best fit obtained gave J(1) = -2.62 +/- 0.19 cm(-1), J(2) = -19.54 +/- 0.47 cm(-1), and g(2) = 2.164 +/- 0.004 cm(-1) (R = 8.28 x 10(-5)) whereas for 2 it gave J(1) = 4.48 +/- 2.73 cm(-1), g(1) = 2.20 +/- 0.03, J(2) = -11.26 +/- 2.01 cm(-1), and g(2) = 2.10 +/- 0.03 (R = 1.15 x 10(-4)). The nature of the superexchange pathways in 1 and 2 is discussed on the basis of structural, magnetic, and molecular orbital considerations. Theoretical calculations are performed at the extended Huckel level in order to obtain their molecular orbitals and energies using their crystallographic data.     

Synthesis and crystal structures of Group 6 metal carbonyl complexes containing S-rich bis(pyrazol-1-yl)methane ligands

The reaction of 3(5)-methylthio-5(3)-phenylpyrazole with dibromomethane under phase-transfer catalytic conditions only affords a new ligand, bis(3-phenyl-5-methylthiopyrazol-1-yl)methane. However, the reaction of 3(5)-methylthio-5(3)-p-methoxyphenylpyrazole or 3(5)-methylthio-5(3)-tert-butylpyrazole with dibromomethane under the same conditions yields three isomers, respectively, indicating that the substituents significantly affect the steric and electronic properties of pyrazole ring during the formation of ligands. Treatment of these potential polydentate ligands with M(CO)₆ (M=Cr, Mo or W) under UV irradiation at room temperature affords (NN)M(CO)₄ derivatives, in which some complexes contain asymmetric substituted bis(pyrazol-1-yl)methane ligands. The X-ray crystal structure analyses indicate that the sulfur atoms in these complexes do not take part in the coordination to the metal centers, and S-rich bis(pyrazol-1-yl)methanes actually act as bidentate chelating ligands by two nitrogen atoms. It is also interesting that in order to reduce the repulsion of methyl groups with carbonyls, the methyl groups in these complexes are oriented away from the metal centers.     

双大环配体与铜双核配合物的合成、晶体结构和磁偶合性质

由新型双功能配体2,6-双(1,5,9-三氮杂环十二烷)-2,6-二甲基苯甲酸(L)与溴化铜在甲醇中反应得到新型铜双核配合物[Cu~2LBr~2]Br.3H~2O单晶。晶体结构分析表明:2个Cu(II)中心离子由配体L中的羧酸基团桥联;2个等价的Cu(II)中心离子均由双功能配体L的1,5,9-三氮杂环十二烷([12aneN~3)的3个氮原子和羧酸的1个氧原子及1个Br^-离子配位,并都处在三角双锥的配位环境中;分子内Cu...Cu双核间的距离为0.5884(6)nm。变温磁化率数据表明:在同一分子中的2个铜核之间存在反铁磁偶合作用(J=-22.49cm^-^1)。     

Synthesis and crystal structure of two Cu(II) complexes with benzimidazole ligands

Two new copper(II) complexes (I, II) with benzimidazole ligands have been synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. Compound I is triclinic, P \(\bar 1\), a = 11.4205(6), b = 13.0956(7), c = 18.2305(9) Å, α = 85.960(1)°, β = 80.388(0)°, γ = 77.517(1)°, V = 2623.0(2) ų, Z = 2; compound II is monoclinic, C2/c, a = 24.2684(11), b = 17.5247(8), c = 19.3149(15) Å, β = 122.710(1)°, V = 6911.9(7) ų, Z = 4. In both compounds, Cu(II) atoms are coordinated by four benzimidazole nitrogen atoms in a slightly distorted tetrahedral fashion.     

Synthesis,structure and optical properties of a CoII complex with bis(2,4,7,8,9-pentamethyldipyrrolylmethen-3-yl)methane

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Synthesis, crystal structure, and magnetic properties of a cobalt(II) complex with (3,5-dichloropyridin-4-yl)(pyridin-4-yl)methanol

A novel bridging ligand, (3,5-dichloropyridin-4-yl)(pyridin-4-yl)methanol (I), and its cobalt(II) complex, [Co(I)₂(NCS)₂]_n (II), were prepared. The structures of ligand I and complex II were determined by single crystal X-ray analysis. Magnetic susceptibility measurements were performed for cobalt (II) complex II. Compound I crystallised in orthorhombic space group Pbca with a = 7.6585(14) Å, b = 12.209(2) Å, c = 23.207(4) Å, V= 2170.0(7) ų and Z=8. Complex II crystallised in monoclinic space group P2₁/n with a = 13.223(8) Å, b = 16.959(10) Å, c = 13.948(8) Å, β = 115.395(10)°, V= 2826(3) ų and Z = 4. Each cobalt(II) ion is surrounded by two NCS^? anions and four pyridyl moieties from two bridging ligands. Each bridging ligand connects two neighbouring Co(II) ions to form a 2-dimensional structure. Temperature dependence of the molar magnetic susceptibilities in the temperature range of 2–300 K revealed that magnetic interactions between the cobalt ions are weak.     

Syntheses,crystal structures and properties of two cadmium coordination polymers containing bis (2-methylimidazol-1-yl)methane(2-mBIM) and bis (imidazol-1-yl)methane (BIM) ligands

Coordination polymers, {[Cd(2-mBIM)₃](ClO₄)₂} _n (1) and [Cd(BIM)₂(NO₃)₂] _n (2), have been prepared from the reaction of bis(2-methylimidazol-1-yl)methane(2-mBIM) with Cd(ClO₄)₂ and bis(imidazol-1-yl)methane (BIM) with Cd(NO₃)₂ in ethanol and water, respectively. Their structures were characterized by single crystal X-ray diffraction and IR spectroscopy. Compound 1 crystallizes in the rhombohedral space group R-3c with a = b = 12.3617(5) Å, c = 38.896(3) Å, γ = 120°, V = 5147.5(5) ų, z = 6. The Cd^II occupies a crystallographic inversion center and is coordinated by six N atoms from six distinct 2-mBIM ligands to form a slightly distorted octahedral geometry. Each 2-mBIM is coordinated to two Cd^II cations, linking alternatively four Cd^II cations, resulting in a 32-membered M₄L₄ macrometallacycle. Compound 2 crystallizes in the monoclinic space group C2/m with a = 14.400(3) Å, b = 9.3894(18) Å, c = 8.6926(17) Å, β = 123.499(2)°, V = 980.1(3) ų, z = 2. The Cd coordinates to four nitrogen atoms from four different BIM and two nitrates to form a slightly distorted octahedral geometry. The BIM ligands bridge to form a 1-D infinite double-bridged chain structure with 16-membered M₂L₂ macrometallacyclic structural units.