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1.
Two trinuclear copper(II) complexes of a Schiff-base type N4O-donor ligand (LH) derived from 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione and 1,3-diaminopropan-2-ol are reported. Complex [Cu3L2(ClO4)4] (1) has an angular C2-symmetric trinuclear core as revealed from single-crystal X-ray diffraction studies. The terminal coppers are in square-pyramidal geometry with an N3O2 coordination environment while the central one is in octahedral geometry with an N2O4 donor environment. Complex [Cu3L2(ClO4)(N3)(H2O)](ClO4)2 · H2O (2) has an unsymmetrical trinuclear core with an intramolecular hydrogen bonding interaction between the water and azide anion coordinated to Cu(1) and Cu(3) center, respectively. All the copper centers in 2 are in square-pyramidal geometry. The average Cu?Cu distance between closest metal ions in both the complexes is 3.897 Å. The coordination environment of coppers in 1 approximately mimics that of multicopper oxidases in the oxidized form and the environment in 2 mimics that of the azide derivative of ascorbate oxidase. Both 1 and 2 exhibit doublet spin ground state due to strong antiferromagnetic coupling operating through the alkoxo-bridged oxygen atoms between the copper centers.  相似文献   

2.
Based on self-assembly of the dissymmetrical mononuclear entity CuL(CH3OH) [H2L = (E)-N1-(2-((2-aminocyclohexydiimino)(phenyl)methyl)-4-chlorophenyl)-N2-(2-benzyl-4-chlorophenyl)oxalamide] with Mn(II), two trinuclear complexes were prepared. They are of the formula [(LCuN3)2Mn(CH3OH)2] · 2CH3OH · 2H2O (1) and [(LCuSCN)2Mn(H2O)2] · 4CH3OH (2). Their magnetic properties were studied by susceptibility versus temperature measurement, the best fitting of the experimental data led to J = −14.40 cm−1 for 1 and J = −15.48 cm−1 for 2. Hydrogen bonds help complex 1 to produce a novel S type one-dimensional chain-like supramolecular structure. In complex 2, Cl?Cl interaction also results in the formation of a one-dimensional structure.  相似文献   

3.
Two oxamido-bridged trinuclear complexes of formula {[(LCu)(EtOH)]2Mn(EtOH)2}(ClO4)2 (1) and {[(LCu)(EtOH)]2Co(EtOH)2}(ClO4)2 · 2H2O (2) (H2L = 2,3-dioxo-5,6:13,14-dichlorobenzo-7,12-diphenyl-1,4,8,11-tetraazacyclo-pentadeca-7,11-diene) have been synthesized and structurally characterized. The central ions of complexes 1-2 (Mn(II), Co(II)) are all bridged by macrocyclic oxamido groups. Their magnetic properties were studied by susceptibility versus temperature measurement, the best fitting of the experimental data led to J = −16.91 cm−1 for 1 and J = −27.73 cm−1 for 2.  相似文献   

4.
Based on the complex ligand (CuL H2L = 2,3-dioxo-5,6:15,16-dibenzo-1,4,8,13-tetraazacyclotetradeca-7,13-diene), which includes macrocyclic oxamido bridge, three trinuclear complexes were prepared. They are of the formula [(CuL)2M(ClO4)2] (M = Co(1), Ni(2)) and [(CuL)2Zn(CH3OH)2] · (ClO4)2 (3). The crystal structures of the three complexes have been determined and the M(II) of the three complexes all exist on the mirror plane. Complex 1 is the first Cu-Co complex bridged by oxamido. Their magnetic properties were studied by susceptibility versus temperature measurement, the best fitting of the experimental data led to J = −28.12 cm−1 for 1, J = −42.88 cm−1 for 2, and J = −2.13 cm−1 for 3.  相似文献   

5.
Three new C3-symmetric tritopic ligands with a central phloroglucinol bridging unit have been synthesized and characterized. The ligands are accessible through Schiff-base condensation of 2,4,6-triformylphloroglucinol with 2-aminomethylpyridine (H3tfpg-ampy), N,N-bis(pyridin-2-ylmethyl)-ethylenediamine (H3tfpg-unspenp), and benzhydrazide (H6tfpg-bhy). These ligands differ in nature and number of the donor atoms within the resulting binding pockets. Based on these ligands the synthesis of the first trinuclear phloroglucinol-bridged nickel(II) complexes with three octahedrally coordinated nickel centers is reported. The ligands H3tfpg-ampy and H6tfpg-bhy, which provide tridentate binding pockets, react with nickel(II) perchlorate in the presence of bis(pyridin-2-ylethyl)-amine (bpea) as an additional tridentate capping ligand leading to the formation of the trinuclear complexes [Ni3(tfpg-ampy)(bpea)3](ClO4)3 and [Ni3(tfpg-bhy)(bpea)3](ClO4)3, respectively. Due to the pentadentate binding pocket in ligand H3tfpg-unspenp, no additional coligand is needed and a water molecule occupies the sixth coordination site at the nickel(II) ion resulting in the complex [Ni3(tfpg-unspenp)(H2O)3](ClO4)3. Temperature-dependent magnetic measurements reveal overall weak antiferromagnetic exchange interactions within the trinuclear complex together with a rather strong zero-field splitting (ZFS) for the nickel(II) ions. The observed isotropic coupling constants for the three complexes are in the range of 0.14 < − J < 0.37 cm−1, whereas for the zero-field splitting parameter ∣D∣ values between 1.8 and 5.5 cm−1 are found. This is indicative for competitive spin-polarization and superexchange mechanisms, with the latter prevailing the interaction between the nickel(II) ions through the meta-phenylene-linkage for the complexes reported.  相似文献   

6.
Three new iron(III) citrate complexes [Fe2(cit)2(H2O)2](H2bpa) (1), [Fe2(cit)2(H2O)2](H2bpe) (2) and [Fe4(cit)4(H2O)4](H2bpp)2(H2O) (3) (cit = C(O)(COO)(CH2COO)2, bpa = 1,3-bis(4-pyridyl)ethane, bpe = 1,3-bis(4-pyridyl)ethene, bpp = 1,3-bis(4-pyridyl)propane) were synthesized and characterized by elemental analysis, spectroscopic techniques and magnetic properties. Single X-ray diffraction analyses in the 1-3 complexes reveal that the iron ion is six-coordinated and is bound by two deprotonated citrates and a pair of aqua ligands in a distorted octahedral fashion. The anionic complex contains a centro-symmetrical planar of four-membered Fe2O2 ring. There are significant contributions to the stabilities of the assembled lattices in 1-3 arising from the protonated pyridine analogue counterions neutralizing the anionic charges of the complexes. The units in the complexes are connected together via hydrogen bonding to form 3D supramolecular networks. The supramolecular structures of 1-2 show alternating and motif linking the anionic moieties which are in turn interwoven with cationic moieties, while 3 shows alternating and motif. The magnetic properties of 1-3 are investigated and discussed in detail.  相似文献   

7.
Two new first-raw transition metal diphosphonate complexes, namely, {[Ni3([hpyedpH)2(H2O)4]·(H2O)2}n (1) and [Mn[hpyedpH2](H2O)]n (2), based on a multidentate ligand 1-hydroxy-2-(3-pyridyl)-ethylidene-1,1-diphosphonic acid (hpyedpH4) have been synthesized under hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy and element analyses. The data reveals that complex 1 is a 2D layer structure, whereas the complex 2 possesses a 1D motif. The powder X-ray diffraction (PXRD) patterns for complexes 1 and 2 were collected as well, which match well with the ones calculated from their single-crystal structure data. Magnetic measurements show that complex 1 is a ferrimagnet with Tc = 5.0 K. Magnetic studies of complex 2 indicate antiferromagnetic behavior.  相似文献   

8.
Using new nitronyl nitroxide radical ligand 2-[4-(1-imidazole)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITPhIm), three new complexes [M(hfac)2(NITPhIm)]2 (M = Cu(II) 1, Mn(II) 2, Co(II) 3; hfac = hexafluoroacetylacetonate) have been prepared. Three complexes possess cyclic dimer structure in which each NITPhIm radical links two different metal ions through the oxygen of nitroxide group and the nitrogen of imidazole. The magnetic studies show the copper(II) ion interacts ferromagnetically with the directly bonding nitronyl nitroxide while manganese(II) and cobalt(II) ions strong antiferromagnetically interact with the directly coordinated nitroxide groups. There is a weak antiferromagnetic coupling between the metal ion and the nitroxide through phenyl and imidazole rings of the radical ligand, which is agreement with spin polarization mechanism. The results show that the minor changes in the structure of radical ligand can change the magnetic behavior of radical-metal complex.  相似文献   

9.
A dissymmetrical double Schiff base Cu(II) mononuclear complex: CuHL (1) (where H3L is N-3-carboxylsalicylidene-N-salicylaldehyde-1,2-diaminoethane) and two trinuclear complexes: [CuL(H2O)CoCuL] · H2O · CH3OH (2) and [(CuL)2Ni] · 2H2O (3) have been synthesized and characterized by means of elemental analyses, IR and electronic spectra. The crystal structures of two heterotrinucler complexes were determined by X-ray analysis. Each dissymmetrical cell unit of the complex 2 contains two heterotrinucler neutral molecules. In each neutral molecule, the central Co2+ ion is located at the site of O6 with a distorted octahedral geometry and one terminal Cu2+ ion at the four-coordination site of N2O2, but the other one at the square-pyramidal environment of N2O3. Each dissymmetrical unit of the complex 3 contains a heterotrinucler neutral molecule, whose structure is similar to that of 2 except two terminal Cu2+ ions both at the inner site of N2O2. The magnetic properties of two heterotrinucler complexes have been determined in the temperature range of 5-300 K, which indicate that the interaction between the central Co2+ ion or Ni2+ ion and the outer Cu2+ ions is antiferromagnetic. The exchange integrals are equal to −26.2 cm−1 for 2 and −50.6 cm−1 for 3.  相似文献   

10.
The heterotrimetallic complex, [{LCuMn(H2O)}{Cr(phen)(C2O4)2}](ClO4) · H2O (1), has been obtained by assembling heterobinuclear cations, [LCuMn]2+, with [Cr(phen)(C2O4)2] ions (H2L is the compartmental Schiff-base resulting from the stepwise condensation of 2,6-diformyl-p-cresol with ethylenediamine and diethylenetriamine). The copper(II) and manganese(II) ions are hosted into the compartments of the macrocyclic ligand. [Cr(phen)(C2O4)2] acts as a ligand, being coordinated through one oxalato oxygen atom to the apical position of the square pyramidal copper(II) ion. The cryomagnetic investigation of 1 reveals an antiferromagnetic interaction between CuII and MnII within the compartmental ligand (J = −39 cm−1). The interaction between CuII and CrIII across the oxalato bridge is negligible. The crystal structure of [LCuPb](ClO4)2 · H2O, a useful precursor in obtaining 3d-3d′ complexes, is also reported.  相似文献   

11.
Three new homopolynuclear complexes with azido bridges have been obtained by using [Cu(AA)(BB)]+ building-blocks (AA = acetylacetonate; BB = 1,10-phenanthroline or 2,2′-bipyridine). The reaction between [Cu(acac)(phen)(H2O)](ClO4) and NaN3 leads to a mixture of two compounds: a binuclear complex, [{Cu(acac)(phen)}21,3-N3)](ClO4) · 2H2O (1), and a linear tetranuclear one, [{Cu(acac)(phen)(ClO4)}2{Cu(phen)(μ1,1-N3)2}2] (2). The reaction between [Cu(acac)(bipy)(H2O)](ClO4) and NaN3 affords also a mixture of two compounds: [{Cu(acac)(bipy)}21,3-N3)]3(ClO4)3 · 3.75H2O (3) and [Cu(acac)(bipy)(N3)][Cu(acac)(bipy)(H2O)](ClO4) (4). The X-ray crystal structures of compounds 1-4 have been solved (for compound 4 the crystal structure was previously reported). In compounds 1 and 3, two {Cu(AA)(BB)} fragments are bridged by the azido anion in an end-to-end fashion. Two isomers, cis and trans with respect to azido bridge, were found in crystal 3. The structure of compound 2 consists of two Cu(II) central cations bridged by two μ1,1-azido ligands, each of them being also connected to a {Cu(acac)(phen)} fragment through another μ1,1-azido ligand. The cryomagnetic properties of the compounds 1 and 2 have been investigated and discussed. The magnetic behaviour of compound 1 shows the absence of any interactions between the metallic ions. In the tetranuclear complex 2, the magnetic interactions between the external and central copper(II) ions(J1), and between the central metallic ions (J2) were found ferromagnetic (J1 = 0.36 cm−1, J2 = 7.20 cm−1).  相似文献   

12.
A trinuclear copper(II) complex, [Cu3(2,5-pydc)2(Me5dien)2(BF4)2(H2O)2] · H2O 1, has been constructed from 2,5-pyridine-dicarboxylato bridges (2,5-pydc2−) and N,N,N′,N″,N″-pentamethyl-diethylenetriamine (Me5dien) acting as a blocking ligand. The copper ions, within the centrosymmetric trinuclear cations, are connected by two 2,5-pydc2− bridges, with an intramolecular Cu···Cu separation of 8.432 Å. The central copper ion exhibits an elongated octahedral geometry, with semicoordinated ions, while the terminal ones are pentacoordinated (distorted square-pyramidal geometry). The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the copper(II) ions (J = −5.9 cm−1, H = −JSCu1SCu2 − JSCu2SCu1a).  相似文献   

13.
The iridium 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) complexes [{κ2(C1,C4)-CRCRCRCR}{CH3C(CH2PPh2)3}Ir(NCMe)]BF4 (2-NCMe, R = CO2Me) and [{κ2(C1,C4)-CRCRCRCR}{CH3C(CH2PPh2)3}Ir(CO)]BF4 (2-CO, R = CO2Me) serve as models for proposed iridium-vinylidene intermediates of relevance to the [2 + 2 + 1] cyclotrimerization of alkynes. The solid-state structures of 2-NCMe, 2-CO, and [κ2(C1,C4)-CRCRCRCR]{CH3C(CH2PPh2)3}Ir(Cl) (2-Cl), were determined by X-ray crystallography.  相似文献   

14.
Two adamantane-1,3-dicarboxylato bridged cobalt(II) phenanthroline complexes [Co2(H2O)2(phen)2(adc)2]·(C2H7N)·2H2O (1) and [Co(H2O)(phen)(adc)]·H2O (2) were synthesized in a mixed solvent under 45 °C (H2adc = adamantane-1,3-dicarboxylic acid). Compound 1 consists of dinuclear [Co2(H2O)2(phen)2(adc)2] complex molecules, dimethylamine (C2H7N) molecules and hydrogen-bonded water molecules. The dinuclear molecules, via intermolecular hydrogen bonds, are interconnected into hydrogen-bonded chains along [1 0 0] and interdigitation of phen ligands due to interchain π?π stacking interactions assembles the hydrogen-bonded chains into 2D supramolecular layers parallel to (0 0 1). In compound 2, the Co(II) ions are bridged by adamantane-1,3-dicarboxylate anions to form 1D chains along [0 0 1], and the resulting chains are assembled into double-chains based on interchain π?π interactions. The double-chains are further held together via hydrogen bonds into 2D supramolecular layers parallel to (1 0 0). The variable temperature magnetic measurements show an overall weak antiferromagnetic behavior for 1, and an weak ferromagnetic behavior over 300-75 K followed by antiferromagnetic behavior below 75 K for 2.  相似文献   

15.
Using an anionic precursor [(Tp)FeIII(CN)3] (1) as a building block, two cyano-bridged centrosymmetric heterotrinuclear complexes, (2) and (3) (en = ethylenediamine), have been synthesized and structurally characterized. In each complex, [TpFe(CN)3] acts as a monodentate ligand toward a central [Mn(C2H5OH)4]2+ or [Ni(en)2]2+ core through one of its three cyanide groups, the other two cyanides remaining terminal. The intramolecular Fe-Mn and Fe-Ni distances are 5.2354(4) and 5.0669(11) Å, respectively. The magnetic properties of complexes 2 and 3 have been investigated in the temperature range of 2.0-300 K. A weak antiferromagnetic interaction between the Mn(II) and Fe(III) ions has been found in complex 2. The magnetic data of 2 can be fitted with the isotropic Hamiltonian: where J and J′ are the intramolecular exchange coupling parameters between adjacent and peripheral spin carriers, respectively. This leads to values of J = −1.37 cm−1 and g = 2.05. The same fitting method is applied to complex 3 to give values of J = 1.2 cm−1 and g = 2.25, showing that there is a ferromagnetic interaction between the Fe(III) and Ni(II) ions.  相似文献   

16.
Two new binuclear radical complexes derived from a new long nitronyl nitroxide ligand, 2-[4-(5-pyrimidyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (4-NITPhPyrim), and M(hfac)2 (M2+ = Cu2+, Mn2+; hfac = hexafluoroacetylacetonato), [Cu(hfac)2(4-NITPhPyrim)]2 · 4H2O (1) and [Mn(hfac)2(4-NITPhPyrim)]2 · 4H2O (2), were synthesized as well as characterized structurally and magnetically. X-ray analysis indicates that 1 and 2 are rectangle-like centrosymmetric dimer M2L2 complexes. Magnetic measurements indicate that there are two types of magnetic exchanges in 1: the ferromagnetic (FM) exchange between the Cu(II) ion and the directly bonded nitroxide unit (J1 = 24.20 cm−1) and the weak FM exchange of Cu-NIT through the pyrimidine and phenyl rings (J2 = 0.62 cm−1). Besides the strong antiferromagnetic (AFM) coupling between the Mn(II) ion and the directly bonded nitroxide unit (J = −87.61 cm−1), there is a weak FM interaction between the two Mn-NIT pairs (θ = 0.39 K) in 2.  相似文献   

17.
Two new coordination polymers [Cd(dps)2Cl2] (1) and [Co(dps)2(H2O)2]·(abs)2(H2O)2 (2) (dps = 4, 4′-dipyridylsulfide, Habs = 4-amino benzenesulfonic acid) have been synthesized under similar conditions and characterized by elemental analysis, fluorescence spectra and single crystal X-ray diffraction. Compound 1 displays a dps-bridged 2D puckered, grid-like layer, which is further linked by C-H?Cl hydrogen bonds to form a 3D supramolecular architecture. Compound 2 shows a dps-bridged double-stranded chain structure, which is extended by N-H?O and O-H?O hydrogen bonds generating a 3D network. Solid-state fluorescence results reveal that both complexes can emit strong emission bands, at 467 nm and 518 nm for 1 and 344 nm for 2, respectively. Magnetic measurements show that there are weak antiferromagnetic interactions between the adjacent Co(II) ions in 2.  相似文献   

18.
The preparation, crystal structures, and magnetic properties of two rhenium(IV) mononuclear compounds of formula NBu4[ReX5(DMF)] with X = Cl (1) and Br (2) are reported. 1 and 2 are isostructural complexes which crystallize in the monoclinic system with the space group P21/n. The rhenium atom is six-coordinated with five X atoms and a DMF molecule forming a somewhat distorted octahedral surrounding [values of Re-X varying in the ranges 2.317(1)-2.358(1) (1) and 2.495(1)-2.518(1) Å (2)]. Magnetic susceptibility measurements on samples of 1 and 2 in the temperature range 1.9-300 K are interpreted in terms of magnetically isolated spin quartets with large values of the zero-field-splitting (|2D| is ca. 20.2 and 39.2 cm−1 for 1 and 2, respectively).  相似文献   

19.
Two new Co(II) coordination polymers with mixed ligands, {[Co(BTA)0.5(DBI)2]·DBI·H2O}n (1) and [Co(PDA)(DBI)(H2O)]n (2) (H4BTA = benzene-1,2,4,5-tetracarboxylic acid; H2PDA = 2,2′-(1,2-phenylene)diacetic acid; DBI = 5,6-dimethyl-1H-benzoimidazole) have been synthesized under hydrothermal conditions, respectively. Both of them are characterized by elemental analyses, powder X-ray diffraction, thermogravimetric analysis, single-crystal X-ray diffraction, and magnetic susceptibilities. In 1, the Co(II) ions are four-coordinated and lie in distorted tetrahedron coordination environment. 1D ladder-like chain structure is formed by the bridging BTA4− ligand. In 2, the Co(II) ions are in slightly distorted octahedral coordination geometry, and linked by PDA2− ligand exhibiting a 2D layer structure. Temperature-dependent magnetic susceptibility measurements of 1 and 2 revealed that there are antiferromagnetic interactions between Co(II) ions.  相似文献   

20.
Using the tetracyanometalate precursor [Fe(4,4′-dmbipy)(CN)4]- (4,4′-dmbipy = 4,4′-dimethyl-2,2′-bipyridine) as the building block, two new cyano-bridged one-dimensional heterobimetallic coordination polymers, [M(CH3OH)2Fe2(4,4′-dmbipy)2(CN)8]n (M = Cu, 1; Mn, 2), have been synthesized and structurally characterized. X-ray crystallography reveals that complexes 1 and 2 consist of heterobimetallic chains of squares, and the central MII ion is six-coordinated as an elongated distorted octahedral geometry. Magnetic studies show ferromagnetic coupling between FeIII and CuII ions in complex 1. Complex 2 exhibits ferrimagnetic behavior caused by the noncompensation of the local interacting spins (SMn = 5/2 and SFe = 1/2), which interact antiferromagnetically through bridging cyanide groups. magpack program has been employed to investigate the magnetic nature of squares chain structure.  相似文献   

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