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1.
Reaction of 4-amino-2-fluoropyridine (2-F-4-AP) with copper halides produced the neutral coordination complexes: (2-F-4-AP)2CuX2 (X = Cl(1), Br(2)). 1 crystallizes in the orthorhombic space group Pccn in a distorted square planar geometry. Magnetic susceptibility data were fit to the uniform chain Heisenberg model resulting in C = 0.439(6)emu-K/mole-Oe and J = ?28(1) K. 2 crystallizes in the monoclinic space group C2/m and is closer to distorted tetrahedral. Intermolecular Br?Cu contacts generate a square layer. Magnetic data show very weak ferromagnetic interactions [C = 0.42(1)emu-K/mol-Oe, J = 0.71(2) K]. Similarly, reaction of 2-F-4-AP with copper halides and aqueous HX in alcohol solvents produced the salts (2-F-4-APH)2CuX4 (X = Cl(3), Br(4)). 3 crystallizes in the triclinic space group P-1. Crystal packing reveals short Cl?Cl contacts which generate a structural ladder. However, analysis of the magnetic data suggests that only the rails of the ladder produce a viable magnetic superexchange pathway; the uniform Heisenberg chain model provides C = 0.449(1)emu-K/mol-Oe and J = -6.9(1) K. 4 is isostructural and is also best fit by a chain model [J = ?2.7(4) K]. The brominated complex (2-F-3-Br-4-APH)2CuBr4·2H2O, 5, (2-F-3-Br-4-APH = 4-amino-3-bromo-2-fluoropyridinium) was serendipitously produced as a byproduct of the synthesis of 4 and was characterized by single-crystal X-ray diffraction.  相似文献   

2.
Three dimeric copper(II) complexes have been prepared with the general formula bis(2-amino-3,5-dihalopyridinium)hexahalodicuprate cuprate(II): (3,5-diCAPH)2Cu2Br6 (1), (3,5-diBAPH)2Cu2Cl6 (2) and (3,5-diBAPH)2Cu2Br6 (3) [3,5-diCAPH = 2-amino-3,5-dichloropyridinium; 3,5-diBAPH = 2-amino-3,5-dibromopyridinium]. The compounds have been characterized via single crystal X-ray diffraction and temperature dependent magnetic susceptibility measurements. All three compounds crystallize in monoclinic space groups (1, C2/c; 2 and 3, P21/c) and exhibit alternating layers of hexahalodicuprate ions and organic cations. The hexahalodicuprate ions exhibit short X?Cu and X?X contacts which link the dimers into a square array. Variable temperature magnetic susceptibility data reveal strong intradimer antiferromagnetic exchange (J = ?153, ?65, ?122 K for 13, respectively), but negligible inter-dimer magnetic exchange.  相似文献   

3.
Abstract

A family of copper(II) compounds has been prepared with the general formula (2-chloro-3-fluoro-pyridine)2CuX2·n(Y), where X?=?Cl, Br, n?=?0,1, and Y?=?methanol or water. For the copper chloride complexes, only solvated structures were obtained (1, X?=?Cl, Y?=?H2O; 2, X?=?Cl, Y?=?CH3OH) while for the copper bromide compounds, both a desolvated structure and the methanol solvate were prepared (3, X?=?Br, Y?=?none; 4, X?=?Br, Y?=?CH3OH). Each compound has been characterized by IR, powder X-ray diffraction, single-crystal X-ray diffraction, and temperature-dependent magnetic susceptibility measurement. Compounds 1 and 4 are isostructural, in the space group Cm, and neither exhibits significant magnetic exchange although superexchange pathways are present. Compound 2 also crystallizes in the Cm space group and exhibits weak ferromagnetic interactions (J/kB?=?1.72(2) K from the 1D-ferromagnetic chain model) which are likely propagated by hydrogen bonding. Compound 3 crystallizes in the space group P21/n with the Cu(II) ion sitting on a crystallographic inversion center. Compound 3 exhibits weak antiferromagnetic exchange via two-halide superexchange typical for similar complexes. The magnetic data for 3 were fit to the 1D-antiferromagnetic chain model resulting in J/kB?=??1.21(1).  相似文献   

4.
The copper(II) complexes [Cu2(phen)2(HL1)2] (ClO4)2 (1) and [Cu2(phen)2(HL2)2] (ClO4)2 (2) synthesized from two potentially tridentate ligands N-(2-hydroxybenzyl) propanolamine (H2L1) and N-(5-methyl-2-hydroxybenzyl) propanolamine (H2L2) have centrosymmetric bis(μ2-phenoxo)-bridged dicopper(II) structures. Variable temperature magnetic measurements have revealed the existence of relatively weak antiferromagnetic interactions (1: 2J=−212.5, 2: 2J=−337.0 cm−1) with respect to the bridging angles (1: θ=101.47(18)°, 2: θ=102.79(12)°). The results suggest that the distortion index of the Cu(II) atoms (1: τ=0.73, 2: τ=0.53) may be the major factor governing the spin coupling between the copper(II) centers of these diphenoxo-bridged binuclear complexes. The coordination moieties of complex 1 are connected into a 1D linear structure via intermolecular hydrogen bonds between alkoxyl, amine, and perchlorate groups.  相似文献   

5.
Five new Cu(II) complexes [Cu(psa)(phen)] · 3H2O (1), [Cu(psa)(2bpy)] · 0.5H2O (2), [Cu(psa)(2bpy)(H2O)] · 3H2O (3), [Cu(psa)(4bpy)] · H2O (4), and [Cu(psa)0.5(N3)(2bpy)] (5) (H2psa = phenylsuccinic acid, phen = 1,10-phenanthroline, 2bpy = 2,2′-bipyridine, and 4bpy = 4,4′-bipyridine) were obtained under solvothermal conditions and characterized by single-crystal X-ray diffraction. Complexes 2 and 3 were formed by one-pot reaction. In complex 2, Cu(II) ion is four-coordinated and locates at a slightly distorted square center. In complex 3, the coordinated water molecule occupies the axial site of Cu(II) ion forming a tetragonal pyramid geometry. Complexes 1 and 3 are of 1D chain structures, and extended into 2D supramolecular network by hydrogen bonds. Complex 2 is of zipper structure, and further assembled into 2D supramolecular network by hydrogen bonds and π–π stacking interactions. Complex 4 is a 3D CdSO4-like structure with twofold interpenetration, while complex 5 is a dinuclear compound. The different structures of complexes 15 can be attributed to using the auxiliary ligands, indicating an important role of the auxiliary ligands in assembly and structure of the title complexes.  相似文献   

6.
Reaction of CoX2 · nH2O with either 2-amino-3-methylpyridine (3-MAP) or 2-amino-5-methylpyridine (5-MAP) in aqueous acid gave complexes, (3-MAPH)2CoX4 or (5-MAPH)2CoX4 (H2O) n [n = 0,1; X = Cl, Br; 3-MAPH = 2-amino-3-methylpyridinium, 5-MAPH = 2-amino-5-methylpyridinium]. The 3-MAPH salts are formed in the triclinic crystal system while the 5-MAPH salts are formed in the monoclinic crystal system. Three of these compounds exhibit weak antiferromagnetic interactions along with varying degrees of single-ion anisotropy, however, 1 shows easy-plane anisotropy and exhibits a mixture of ferromagnetic and antiferromagnetic interactions.  相似文献   

7.
The crystal and molecular structures of Ni(II) complexes with two tridentate anthracene-containing Schiff bases are reported. The Schiff bases were prepared by condensation of 9-anthraldehyde with diethylenetriamine (adien) and with dipropylenetriamine (adipn). Complexes synthesized from Ni(O2CCH3)2·4H2O and the ligands (1?:?1 mol ratio) crystallize from methanol as [Ni(adien)(O2CCH3)2(H2O)] (1) and [Ni(adipn)(O2CCH3)2]·2CH3OH (2·2CH3OH) in space groups P21/n and P212121, respectively. In 1, the distorted octahedral N3O3 coordination sphere around the metal ion is formed by the meridional N3-donor adien, two mutually trans unidentate acetates and one water molecule. The N3O3 coordination sphere constituted by the N3-donor adipn, one unidentate acetate and one bidentate acetate in 2 can be best described as trigonal bipyramidal. The secondary amine-N of adipn, the O-atom of the unidentate acetate and the midpoint of the two O-atoms of the bidentate acetate occupy the three equatorial positions and two imine-N atoms of adipn lie in axial sites. In the crystal lattice, molecules of 1 exist as discrete dimers due to intermolecular hydrogen bonding and π–π interactions. In contrast, self-assembly of 2 via intermolecular π–π interactions leads to a one-dimensional supramolecular structure.  相似文献   

8.
Physico-chemical properties of 4-chloro-2-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono- and trihydrates with a metal ion to ligand ratio of 1:2. All analysed 4-chloro-2-nitrobenzoates are polycrystalline compounds with colours depending on the central ions: pink for Co(II), green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293–523 K, because it was found that on heating in air above 523 K 4-chloro-2-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step and anhydrous compounds are formed. The final products of their decomposition are the oxides of the respective transition metals. From the results it appears that during dehydration process no transformation of nitro group to nitrite takes place. The solubilities of analysed complexes in water at 293 K are of the order of 10–4–10–2 mol dm–3. The magnetic moment values of Co2+, Ni2+ and Cu2+ ions in 4-chloro-2-nitrobenzoates experimentally determined at 76–303 K change from 3.89 to 4.82 μB for Co(II) complex, from 2.25 to 2.98 μB for Ni(II) 4-chloro-2-nitrobenzoate, and from 0.27 to 1.44 μB for Cu(II) complex. 4-chloro-2-nitrobenzoates of Co(II), and Ni(II) follow the Curie–Weiss law. Complex of Cu(II) forms dimer.  相似文献   

9.
Four new heterotrinuclear complexes have been synthesized and characterized, namely {[Ni(L)2]2[Cu(opba)]}(ClO4)2, where opba denotes o-phenylenebis(oxamato) and L stands for 1,10-phenanthroline(phen) (1), 5-nitro-l,10-phenanthroline(NO2-phen) (2), 2,2′-bipyridyl(bpy) (S) and 4,4′-dimethyl-2,2′-bipyridyl(Me2bpy) (4). The temperature dependence of the magnetic susceptibility of {[Ni(phen)2]2[Cu(opba)]}(ClO4)23H2O has been studied in the 4–300 K range, giving the exchange integral J—109 cm?1. The HMT vs. T plot exhibits a minimum at about 100 K, characteristic of this kind of coupled polymetallic complex with an irregular spin-state structure.  相似文献   

10.
Two new complexes of imidazole alcohols, 4-hydroxymethylimidazole (4-CH2OHim) and 4-hydroxymethyl-5-methylimidazole (4-CH2OH-5-CH3im), with cobalt(II) of formula [CoL2(H2O)2](NO3)2 were obtained. These compounds were described through single X-ray diffraction studies, spectroscopic (Ir. Far-IR, UV-Vis-NIR) and magnetic measurements. In the present complexes imidazole ligands are bidentate coordinating the heterocyclic ring through pyridine-like nitrogen and the oxygen atom of the hydroxymethyl group (chromophore CoN2O4). The shape of Co(II) coordination polyhedra is that of a distorted octahedron, with the equatorial plane defined by the 4-CH2OHim (or 4-CH2OH-5-CH3im) bidentate ligands and two water molecules occupying axial positions (i.e. trans to each other). Formation of successive cobalt(II) complexes with 4-CH2OH-5-CH3im in aqueous solution was followed quantitatively by potentiometry.  相似文献   

11.
Three supramolecular complexes [Zn(HL1 )2(H2O)2(ZnCl4)2] (1), [Cu(L2 )2Cl2] (2), and [Zn(L3 )Cl2] (3) have been synthesized and characterized by single crystal X-ray diffraction analysis (L1 = 3,5-di(2-pyridyl)-4-amino-1,2,4-triazole, L2 = 3,5-di(2-pyridyl)-1,2,4-triazole, and L3 = 2-pyridinecarboxylic acid (pyridin-2-ylmethylene)-hydrazide). In 1, anion–π interactions between Cl? and the π-systems of L1 are observed and anion–π, hydrogen bonding and π–π stacking interactions link the two complex units of [Zn(HL1 )2(H2O)2]4+ and [ZnCl4]2? to form a 3-D supramolecular network. In 2, π–π stacking interactions between aromatic rings of 1,2,4-triazole and pyridine rings are observed; in 3, hydrogen bonding of Cl ··· H–N and π–π stacking interactions between parallel pyridine rings of L 3 are observed. The mechanisms of rearrangement reactions of L to L1 L3 are discussed. The fluorescent properties for solid 1 and 3 are also investigated.  相似文献   

12.
Five new complexes of copper(II) having the general formula [CuL(OAc)], where HL and OAc represent the N,N,O-donor 4-R-2-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol (R = H, Br, NO2 and OMe) or 5-methoxy-2-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol and acetate, respectively have been reported. The complexes have been synthesized in 52–80% yields by reacting one mole equivalent each of Cu(OAc)2·H2O, 2-(2-aminoethyl)pyridine and the appropriate substituted salicylaldehyde in methanol. The solid state effective magnetic moments of the complexes at 298 K are within 1.79–1.97 μB. In solution, all the complexes are electrically non-conducting. The electronic spectra of these species display a weak ligand-field band within 640–615 nm and several strong charge transfer bands in the range 410–235 nm. The complexes are EPR active. The frozen (120 K) solution spectral parameters are g|| = 2.22–2.23, A|| = 189–191 × 10−4 cm−1, gg = 2.06–2.07, and A(N)A(N) = 10–16 × 10−4 cm−1. X-ray structures show that the ligand L coordinates the metal center through the phenolate-O, the imine-N and the pyridine-N and forms two six-membered chelate rings. The acetate is bidentate but asymmetric with respect to the Cu–O as well as C–O bond lengths. Only the complex where R = Br dimerises due to two reciprocal Cu?Br interactions.  相似文献   

13.
14.
《Polyhedron》2001,20(28):306-3306
Five new complexes of composition [Cu(dpt)Ni(CN)4] (1) (dpt=dipropylenetriamine), [Cu(dien)Ni(CN)4]·2H2O (2) (dien=diethylenetriamine), [Cu(N,N′-dimeen)Ni(CN)4]·H2O (3) (N,N′-dimeen=N,N′-dimethylethylenediamine), [Cu(N,N-dimeen)Ni(CN)4]·H2O (4) (N,N-dimeen=N,N-dimethylethylenediamine) and [Cu(trimeen)Ni(CN)4] (5) (trimeen=N,N,N′-trimethylethylenediamine) have been obtained by the reactions of the mixture of Cu(ClO4)2·6H2O, appropriate amine and K2[Ni(CN)4] in water and have been characterized by IR and UV–Vis spectroscopies and magnetic measurements. The crystal structure of [Cu(dpt)Ni(CN)4] (1) has been determined by single-crystal X-ray analysis. The structure of 1 consists of a one-dimensional polymeric chain ---Cu(dpt)---NC---Ni(CN)2---CN---Cu(dpt)--- in which the Cu(II) and Ni(II) atoms are linked by CN groups. The nickel atom is four coordinate with four cyanide-carbon atoms (two cyano groups are terminal and two cyano groups (in cis fashion) are bridged) in a square-planar arrangement and the copper atom is five coordinate with two cyanide-nitrogen and three dpt-nitrogen atoms, in a distorted square-pyramidal arrangement. The temperature dependence of magnetic susceptibility (2–300 K) was measured for compound 1. The magnetic investigation showed the presence of a very weak antiferromagnetic interaction (J=−0.16 cm−1) between the copper atoms within each chain through the diamagnetic Ni(CN)4 2− ions.  相似文献   

15.
The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. Two types of aroylhydrazones derived from aroylhydrazines and ortho-hydroxy aldehydes or 2-pyridine-carboxaldehyde have been used. The characterization of the complexes has been performed with the help of various physico-chemical techniques. Solid state structural patterns have been established by X-ray crystallography. In the solid state, structural varieties of these complexes are seen to range from monomeric, dimeric, polymeric and one-dimensional self-assembly via hydrogen bonds and π-π interactions. EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic characteristics of these complexes.  相似文献   

16.
The structures of 41 Ni(II) and 17 Cu(II) complexes of macrocyclic quadridentate ligands have been analyzed, and are discussed about bond lengths, bond angles, conformations, and configurations, upon which many conclusions are formed. The inter- or intra-molecular hydrogen bonds exist among ligands and hydrates in many compounds and play an important role in the structures. There are exhibited two distinct peaks on the histogram of the average Ni-N distances, corresponding to four coordination and six coordination; these average Ni-N distances are 1.95(4) Å and 2.10(5) Å, respectively. The most probable structures of Ni(II) macrocyclic compounds have coordination number six for the metal ion, chair forms for six-membered rings, planar structure for the metal ion and the four donor atoms of the quadridentate ligand and an inversion center at the central metal ion.  相似文献   

17.
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.  相似文献   

18.
A new series of binuclear unsymmetrical compartmental oxime complexes (15) [M2L] [M=Cu(II), Ni(II)] have been synthesized using mononuclear complex [ML] (L=1,4-bis[2-hydroxy-3-(formyl)-5-methylbenzyl]piperazine), hydroxylamine hydrochloride and triethylamine. In this system there are two different compartments, one has piperazinyl nitrogens and phenolic oxygens and the other compartment has two oxime nitrogens and phenolic oxygens as coordinating sites. The complexes were characterized by elemental and spectral analysis. Electrochemical studies of the complexes show two step single electron quasi-reversible redox processes at cathodic potential region. For copper complexes E1 pc=−0.18 to −0.62 and E2 pc=−1.18 to −1.25 V, for nickel complexes E1 pc=−0.40 to −0.63 and E2 pc=−1.08 to −1.10 V and reduction potentials are sensitive towards the chemical environment around the copper and nickel atoms. The nickel(II) complexes undergo two electrons oxidation. The first one electron oxidation is observed around +0.75 V and the second around +1.13 V. ESR Spectra of the binuclear copper(II) complexes [Cu2L](ClO4), [Cu2L(Cl)], [Cu2L(NO3)] shows a broad signal at g=2.1 indicating the presence of coupling between the two copper centers. Copper(II) complexes show a magnetic moment value of μeff around 1.59 B.M at 298 K and variable temperature magnetic measurements show a −2J value of 172 cm−1 indicating presence of antiferromagnetic exchange interaction between copper(II) centres.  相似文献   

19.
Two temperature-dependent Cu(II) compounds, [Cu(mpdaH)2(H2O)4] · 4H2O (1) and [Cu(mpdaH)2] n (2) (H2mpda = 2,6-dimethylpyridine-3,5-dicarboxylic acid), have been synthesized under hydrothermal conditions and characterized by X-ray single crystal diffraction, elemental analysis, thermogravimetric analyses, and IR spectra. The structure at room temperature confirms that 1 is mononuclear with the octahedral coordination geometry. However, on warming to 120°C the same reaction gives 2, in which copper(II) has square planar coordination and is further bridged by mpdaH? ligands to form extended 2-D layers with parallelogram-like (4,4) topology. Furthermore, in both complexes, through π–π stacking and hydrogen bonding interactions, 3-D supramolecular networks are assembled.  相似文献   

20.
Complexes CuL3Cl2, PdL2Cl2 and PtL2Cl2, where L is a novel ligand from the series of 2-substituted 5-aminotetrazoles, namely 5-amino-2-tert-butyltetrazole (1), have been synthesized by the reaction of metal(II) chlorides with 1 and characterized by IR spectroscopy, thermal and X-ray analyses. The crystallographic structural analysis of these complexes revealed that 1 acts as a monodentate ligand coordinated to the metal via endocyclic N4 atom. Platinum complex demonstrates promising cytotoxicity against human cervical carcinoma cells with IC50 value average between those of cisplatin and carboplatin.  相似文献   

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