Synthesis,characterization and magnetic analysis of binuclear nickel(II) terephthalato complexes

Six new binuclear nickel (II) complexes have been synth-esized and characterized, namely: [Ni2(4X-TP-HA)(L)4](ClO4)2 [L = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO2-phen) or 2,2-bipyridyl (bipy)], where 4X-TPHA is the tetrabromoterephthalate dianion (X = Br) or the tetraiodoterephthalate dianion (X = I). Based on i.r. spectra, elemental analyses and conductivity measurements, these complexes are proposed to have terephthalato-bridged structures containing two NiII ions, each in a distorted octahedral environment. The temperature dependences of the magnetic susceptibility for [Ni2(4Br-TPHA)(phen)4]- (ClO4)2·H2O (1) and [Ni2(4I-TPHA)(phen)4]-(ClO4)2·- 2H2O (4) were measured over the 4–300K range and the observed data indicate weak antiferromagnetic spin exchange interaction between the metal ions.     

Synthesis and magnetism of tetrachlorophthalato-bridged manganese(II) binuclear complexes

Summary Four novel manganese(II) binuclear complexes have been prepared and characterized, namely [Mn₂(TCPHTA)(L)₄]-(ClO₄)₂ [where L is 2,2-bipyridyl (bipy), 1,10-phenanthroline (phen), 4,4-dimethyl-2,2-bipyridyl (Me₂bipy) or 5-nitro-1,10-phenanthroline (NO₂-phen) and TCPHTA is the tetrachlorophthalate dianion]. Based on i.r. spectra, elemental analyses, conductivity measurements, extended tetrachlorophthalato-bridged structures consisting of two manganese(II) ions in which each manganese(II) ion has a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for [Mn₂(TCPHTA)(phen)₄]-(ClO₄)₂·H₂O was measured over the 4–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator ( = –2J ₁· ₂), giving the exchange integralJ = –1.05 cm^–1. This result is indication of a weak antiferromagnetic spin exchange interaction between the metal ions.     

Synthesis,characterization and crystal structure of ruthenium(II) polypyridyl complexes

[Ru(bipy)2(5-R-phen)](ClO4)2 complexes have been prepared, where bipy=2,2- bipyridine, phen=1,10-phenanthroline, and R=H, Me, NO2 or NH2. The influence of the different 5- substituted phen on the electron delocalization and ligand-ligand interactions have been investigated by solution n.m.r.. The ligand- ligand interaction has also been observed in the solid state by determining the single crystal structure of [Ru(bipy)2(5- NO2-phen)](ClO4)2. The strong steric interaction between the polypyridyl ligands was relieved neither by the elongation of Ru–N bonds (2.055–2.086Å) nor by increase of N–Ru–N bite angles (77.8–79.4°), but rather by distortion of the coordination sphere by forming specific angles (=2.0, 3.2 and 4.2°) between the polypyridyl ligand planes and coordination planes (N–Ru–N), and larger torsion angles (5.8 and 8.2°) between the two pyridine rings for each bipy.     

N,N'-双(2-氨基丙基)草酰胺合铜(II)的铜(II)-锰(II)配合物的合成和磁性

合成和表征了两种新的异双核配合物[Cu(oxap)Mn(L)~2](ClO~4)~2, oxap表示N,N'-双(2-氨基丙基)草酰胺根阴离子, L表示1,10-邻菲咯啉(phen)和5-硝基-1,10-邻菲咯啉(NO~2-phen)。测定了配合物的变温磁化率(4.2-300K), 并用最小二乘法和从自旋Hamiltonian算符, ^^H=-2J^^S~1.^^S~2-D^^S~Z~1导出的磁方程拟合。求得交换积分为J=-74.72cm^-^1(phen)和J=-76.39cm^-^1(No~2-phen), 表明两个Cu(II)-Mn(II)双核配合物中有中等强度的反铁磁超交换作用。     

Synthesis and magnetism of binuclear cobalt(II) complexes with the tetraacetylethene dianion as a bridging ligand

Three novel binuclear CoIIcomplexes, [Co2(TAE)-(phen)4](ClO4)2·3H2O(1),[Co2(TAE)(Nphen)4](ClO4)2 ·4H2O(2) and [CO2(TAE)(bipy)4](ClO4)2·H2O(3) (TAE=tetraacetylethene dianion, phen=1,10–phenanthroline, Nphen=5–nitro·1,10–phenanthroline, bipy =2,2-bipyridy1), have been synthesized and characterized by elemental analysis, i.r., molar conductance and electronic reflection spectra. The complexes are proposed to contain tetraacetylethene dianion bridged structures and two CoII ions. The variable-temperature magnetic susceptibility of complex (1) was measured in the 4–300 K range. The magnetic coupling parameter is consistent with antiferromagnetic exchange between the two CoII centres and the data fit a binuclear magnetic exchange model based on the Hamiltonian operator ( = –2 J12, S1=S2=3/2), giving the antiferromagnetic coupling parameter of 2J=–1.55cm–1.     

O-phenylenebis(oxamato) bridged trinuclear copper(II) complexes: synthesis and magnetic properties

Summary Four new trinuclear copper(II) complexes bridged by o-phenylenebis(oxamato) (opba) and end-capped with 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO₂-phen), 2,2-bipyridyl (bipy) or 4,4-dimethyl-2,2-bipyridyl (Me₂bipy), {[Cu(opba)][Cu(L)]₂}(ClO₄)₂ (L = phen, NO₂-phen, bipy or Me₂bipy), have been synthesized and characterized. Based on i.r., elemental analyses, conductivity measurements and electronic spectra, oxamato-bridged structures consisting of three copper(II) ions in which each copper(II) ion has a square-planar environment are proposed. The temperature-dependent magnetic susceptibility of {[Cu(opba)][Cu(phen)]₂} (ClO₄)₂ has been studied in the 4.2–300 K range, giving the exchange integral J = -134.4cm^–1. The result revealed the operation of an antiferromagnetic spin-exchange interaction between the adjacent copper ions.     

The first oxalato-bridged dinuclear CoII–VIVO complexes: synthesis and magnetism

Two novel CoII–VIVO oxalato complexes have been synthesized and characterized, namely [CoL2VO(OX)2·3H2O [L = 1,10-phenanthroline (phen) or 2,2-bipyridyl (bipy), OX = oxalate dianion]. Based on i.r. and electronic spectra and elemental analyses, extended oxalato-bridged structures consisting of VO2+ and CoII species, in which each VIV has a distorted square pyramidal environment and each CoII has a distorted octahedral environment are proposed for the two complexes. The temperature dependence of the magnetic susceptibility for [CoL2VO(OX)2]·3H2O (L = phen, bipy) was measured over the 77–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator H^=–2JS^1S^2 giving the exchange integral J=–62.5 cm–1 and J=–40.3 cm–1 for the phen and bipy complexes, respectively. These indicate antiferromagnetic spin exchange interaction between the CoII and VO2+ centres.     

Synthesis and magnetic properties of trinuclear nickel(II) complexes bridged by α-benzyldioximato groups

Four new NiII–NiII–NiII homotrinuclear complexes namely [Ni(-BD)2{NiL2}](ClO4)2 [L = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (5-NO2-phen), 2,2-bipyridyl (bpy) or 4,4-dimethyl-2,2bipyridyl (Me2bpy) and (-BD)– = -benzyldioximato ion] have been prepared and characterized. Based on elemental analyses, i.r. spectra, conductivity measurements, extended -benzyldioximato-bridged systems consisting of three nickel(II) ions in which the central nickel(II) ion has a square-planar environment and the end capped two nickel(II) ions have a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for complexes (1) (phen), (2) (5-NO2-phen), (3) (bpy) and (4) (Me2bpy) were measured over the 77–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator (H^ = –2JS^1S^2), giving the exchange integral J = –13.31 cm–1 for (1), J = –7.37 cm–1 for (2), J = –8.96 cm–1 for (3) and J = –7.33 cm–1 for (4) These results indicate a weak antiferromagnetic spin exchange interaction between the two terminal nickel(II) io     

Syntheses and magnetic properties of O-phenylenebis(oxamato)-bridged CoIICuIICoII complexes

Four new heterotrinuclear complexes have been prepared and characterized, namely {[Co(L)2]2[Cu (opba)]}(ClO4)2, where opba=o-phenylenebis(oxamato) and L=1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO2-phen), 2,2-bipyridyl (bpy) and 4,4-dimethyl-2,2-bipyridyl (Me2bpy). The temperature dependence of the magnetic susceptibility of {[Co(phen)2]2[Cu(opba)]}(ClO4)2 has been studied in the 4–300K range, the MT versus T plot exhibits a minimum at ca. 131K, but abnormal magnetic behaviour below 83K.     

Generation of a heterobimetallic FeMoS system containing intermediate spin [FeIIN4S2] functionality: Synthesis,characterisation and redox chemistry of [(N–N)2FeS2MoS2] (N–N=bipy or phen)

Tetrathiomolybdate reacts with iron (II) in the presence of bidentate ligands to form neutral binuclear complexes [Fe(N–N)₂MoS₄] [N–N=2-2bipyridine(bipy) and 1,10-phenanthroline(phen)] showing intermediate spin character for Fe^II. The spin state of the complexes has been examined by variable temperature magnetic moment (VTM) measurements and by variable temperature Mössbauer spectroscopy. The Mössbauer spectra indicate the presence of two iron sites: one of intermediate spin and the other of low spin at room temperature. The low spin site predominates over the intermediate spin as the temperature is lowered. The structural features of the complexes are supported by i.r., Raman, electronic and FAB mass spectra and by X-ray powder diffraction data. Substitution of one bipy/phen ligand in [Fe(N–N)₃]²⁺ by MS₄ ^2– ligands does not impart any major effect towards the size of the redox potentials of the tris-bipy/phen complexes, although the reversible nature of their cyclic voltammetric response is affected.     

Synthesis and magnetism of 2-hydroxy-1,3-propanediylbis-(oxamato) bridged trinuclear copper(II) complexes

Summary Four novel trinuclear copper(II) complexes have been synthesized, namely {[Cu(pbaOH)][Cu(L)]₂}(ClO₄)₂, where pbaOH = 2-hydroxy-1,3-propanediylbis(oxamato) and L is 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO₂-phen), 2,2-bipyridyl (bipy) or 4,4-dimethyl-2,2-bipyridyl (Me₂bipy). Based on i.r. and electronic spectra, elemental analyses, and conductivity measurements oxamato-bridged structures consisting of three copper(II) ions, in which each copper(II) ion has a square-planar environment, are proposed. The temperature-dependent magnetic susceptibility of {[Cu-(pbaOH)][Cu(phen)]₂}(ClO₄) ₂ has been studied in the 4.2–300 K range, giving the exchange integral J=- 111.9cm^–1. The result revealed the operation of an antiferromagnetic spin-exchange interaction between adjacent copper ions.     

2–Hydroxy–1,3–propylene bis (oxamato)–bridged new NiIICuIINiII trinuclear complexes with an S = 3/2 high-spin ground state: synthesis and magnetism

Four new heterotrinuclear complexes have been synthesized and characterized, namely {[Ni(L)2]2[Cu(pbaOH)]}(ClO4)2, where pbaOH denotes 2–hydroxy–1,3–propylenebis(oxamato) and L = 1,10–phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO2–phen), 2,2–bipyridyl (bpy) and 4,4–dimethyl–2,2–bipyridyl (Me2bpy). The temperature dependence of the magnetic susceptibility of {[Ni(phen)2]2[Cu(pbaOH ]}(ClO4)2·H2O has been studied in the 4–300 K range, giving an exchange integral J = –94 cm– . The MT versus T plot exhibits a minimum at ca. 93 K, characteristic of this type of coupled polymetallic complex with an irregular spin-state structure.     

1,3-亚丙基双(草胺酸根)桥联的Gd(Ⅲ)Cu(Ⅱ)Gd(Ⅲ)三核配合物

合成和表征了三种新的异三核配合物, {[Gd(L)2]2[Cu(pba)]}(ClO4)4,其中pba为1,3-亚丙基双(草胺酸根)和L表示1,10-菲咯啉(phen),5-硝基-1,10-菲咯啉(NO2-phen)或2,2'-联吡啶(bpy)。基于{[Gd(phen)2(ClO4)]2[Cu(pba)]}(ClO4)2.2H2O的变温磁化率测量(4.1~300K),求出交换积分J=3.576cm^-^1。表明在铜(Ⅱ)和钆(Ⅲ)离子间存在铁磁性偶合。     

诺氟沙星-铜（Ⅱ）-邻菲咯啉配合物的SOD活性及电化学性能

应用氯化硝基四氮唑蓝（NBT）-光照法研究了配合物[Cu（NFA）（phen）（H2O）]（ClO4）2（1）和[Cu（NFA）（5-NO2-phen）（H2O）]（ClO4）2（2）[NFA=1-乙基-6-氟-1,4-二氢-4-氧代-7-（1-哌嗪基）-3-喹啉羧酸（诺氟沙星）;phen=1,10-菲咯啉;5-NO2-phen=5-硝基-1,10-菲咯啉]在水溶液中的SOD活性,并用循环伏安法研究了配合物的电化学性质.结果表明：配合物（1）和（2）均具有良好的SOD活性,表观催化速率常数分别为6.32×10^7和5.12×10^7L·mol-1·s-1.     

Synthesis and magnetism of a binuclear copper(II)–manganese(II) complex with N,N-bis(N-hydroxyethylaminoethyl)oxamido as a bridging ligand

The heterobinuclear complex, [CuMn(L)(phen)2](ClO4)2· H2O, [L = N,N-bis(N-hydroxyethyleneamine)oxamido, phen=1,10-phenanthroline], has been synthesized with N,N-bis(N-hydroxyethylaminoethyl)oxamido as the bridging ligand. The electronic reflectance spectrum indicates the presence of exchange-coupling interaction between bridging MnII and CuII ions. The variable-temperature magnetic susceptibility of the complex was measured over the 4–300K range. The magnetic coupling parameter is consistent with an antiferromagnetic exchange between the MnII ion and CuII ion and fits the data for a heterobinuclear CuII–MnII magnetic exchange model based on the Hamiltonian operator (H= –2JS1S2, S1=1/2, S2=5/2), giving the antiferromagnetic coupling parameter of 2J=–74.0cm–1.     

First oxalate-bridged pentanuclear [Cu(L)]3[Mn(ox)3]2 complexes: synthesis and magnetism

Two novel CuII3MnIII2 pentanuclear oxalato complexes have been synthesized and characterized, namely [Cu(L)]3[Mn(ox)3]2 [L = 1,10-phenanthroline(phen) and 2,2-bipyridyl(bipy)] where ox is the oxalate dianion. Based on i.r., elemental analyses and electronic spectra, thesecomplexesareassignedtoextendedoxalato-bridged structures consisting of two manganese(III) ions and three copper(II) ions, in which each manganese(III) has a distorted octahedral environment and each copper(II) ion a distorted square pyramidal environment. The temperature dependance of the magnetic susceptibility for [Cu(phen)]3[Mn(ox)3]2·4H2O was measured over the 4.2–300K range and the observed data indicates antiferromagnetic spin exchange interaction between the CuII and MnIII ions.     

Synthesis, characterization and magnetism of μ-chloranilato bi-nuclear chromium (III) complexes

Five new chloranilato-bridged binuclear chromium (III) complexes have been synthesized and identified as [Cr2(CA)L4]-(ClO4)4[L denotes 5-methyl-1,10-phenanthroline (Me-phen); 2,9-dimethyl-1, 10-phenanthroline ( Me2-phen); 5-chloro-1,10-phenanthroline(Cl-phen); diaminoethane (en) or 1,3-diaminopropane (pn)], where CA represents the dianion of chloranilic acid. Based on elemental analyses, molar conductivity and magnetic moment of room-temperature measurements, and IR and electronic spectral studies, it is proposed that these complexes have CA-bridged structures and consist of two chromium (III) ions, each in an octahedral environment. The complexes [Cr2(CA)(Me-phen)4](ClO4)4(1) and [Cr2(CA)(Me2-phen)4](ClO4)4(2) were further characterized by variable temperature (4.2-300 K) magnetic susceptibility measurements and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, , giving the exchange parameter J = -7.8 cm-1 for (1) and J= -6.5 cm*1 for (2). This result     

Synthesis and magnetic properties of heterobinuclear copper(II)–iron(II) complexes with N,N′-bis(2-aminopropyl)oxamidocopper(II)

Six new -oxamido heterobinuclear complexes, namely [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N,N-bis(2-aminopropyl)oxamido dianion and L represents 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen); 5-methyl-1,10-phenanthroline (Me-phen); 2,2-bipyridine (bpy); and 4,4-dimethyl-2,2-bipyridine (Me2bpy), have been synthesized and characterized by elemental analyses, i.r. spectra, electronic spectra, magnetic moments (at room temperature) and molar conductivity measurements. The temperature dependent magnetic susceptibilities of [Cu(oxap)Fe(bpy)2]SO4 (1) and [Cu(oxap)Fe(phen)2]SO4 (2) have been studied in the 4.2–300K range, giving the exchange integrals J=–20.9cm–1 for (1) and J=–22.5cm–1 for (2). These results are commensurate with antiferromagnetic interactions between adjacent metal ions within each molecule.     

New Ni(Ⅱ)Cu(Ⅱ)Ni(Ⅱ) trinuclear complexes with an S=3/2 high-spin ground state

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-1,10-phenanthroline(NO2-phen) (2), 2,2'-bipyridyl(bpy) (3) and 4,4'-dimethyl-2,2'-bipyridyl(Me2bpy) (4). The temperature dependence of the magnetic susceptibility of {[Ni(phen)2]2[Cu(opba)]}(ClO4)2.3H2O has been studied in the 4-300 K range, giving the exchange integral J=-109 cm-1. The MT vs. T plot exhibits a minimum at about 100 K, characteristic of this kind of coupled polymetallic complex with an irregular spin-state structure.     

Synthesis and magnetic properties of tetrabromophthalato-bridged manganese(II) binuclear complexes

Summary Four novel Mn^II binuclear complexes have been prepared and characterized, namely: [Mn₂(TBPHTA)(L)₄](ClO₄)₂ [L = 2,2-bipyridyl (bipy), 1,10-phenanthroline (phen), 4,4-dimethyl-2,2-bipyridyl (Me₂bipy) and 5-nitro-1,10-phenanthroline (NO₂-phen), respectively], and TBPHTA = the tetrabromophthalate dianion. Based on i.r. spectra, elemental analyses and conductivity measurements, extended tetrabromophthalato-bridged structures consisting of two Mn^II ions, in which each Mn^II ion has a distorted octahedral environment, are proposed for these complexes. The temperature dependence of the magnetic susceptibility for [Mn₂(TBPHTA)(phen)₄] (ClO₄)₂·H₂O was measured over the 4–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator ( = -2J _{1 2}), giving the exchange integral J = -1.22 cm^–1. This result indicates a weak antiferromagnetic spin exchange interaction between the metal ions.