Synthesis, characterization and magnetic properties of μ-iodanilato dinuclear oxovanadium (Ⅳ) complexes

Five oxovanadium(Ⅳ) dinuclear complexes described by the overall formula [(VO)2(IA)L2]-SO4, where IA represents the dianion of iodanilic acid and L denotes 2,2'-bipyridine (bpy) ; 4,4'-dimethyl-2,2'-bipyridine (Me2-bpy); 1,10-phenanthroline (phen); 4,7-diphenyl-1, 10-phenanthroline (Ph2-phen) and 5-nitro-l, 10-phenanthroline (NO2-phen) , have been synthesized and characterized by elemental analyses, molar conductivity and room-temperature magnetic moment measurements, IR and electronic spectral studies. It is proposed that these complexes have IA-bridged structures and consist of two oxovanadium(Ⅳ) ions each in a square- pyramidal environment. The complexes [ ( VO)2 (IA) (bpy )2 ] SO4 (1) and [ ( VO )2 ( IA) ( phen)2 ] -SO4 (2) were further characterized by variable temperature (4.2-300 K) magnetic susceptibility measurements and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method, giving the exchange integral J = -2.15 cm-1 for 1 and J = - 9.88 cm-1 for 2     

Synthesis and magnetic interaction of μ-2-chloroterephthalato binuclear iron (Ⅱ) complexes

Four μ-2-chloroterephthalato binuclear iron(Ⅱ) complexes, namely [Fe2 (CTPHA) L4]-(ClO4)2, where L stands for 4,4'-dimethyl-2,2'-bipyridine (Me2-bpy); 2,9-dimethyl-l, 10-phenanthro-line (Me2-phen); 5-chloro-l, 10-phenanthroline (Cl-phen); 4, 7-diphenyl-l, 10-phenanthroline (Ph2-phen), respectively, and CTPHA represents 2-chlorolerephthalate dianion, have been synthesized and characterized. Based on the elemental analyses, molar conductance measurements and spectroscopic studies, extended CTPHA-bridged structures consisting of two iron(Ⅱ) ions, each in a distorted octahedral environment, are proposed for these complexes. [Fe2 CTPHA)-(Me2-bpy)4] (ClO2 (1) and [Fe2(CT-PHA)·(Me2-phen)4](ClO4)2 (2) complexes were characterized by variable temperature magnetic susceptibility (4-300 K) measurements and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = - 2JS1 · S2 , giving the exchange integrals J = - 1.28 cm-1 for 1 and J = - 1.85 cm-1 for 2. These r     

Synthesis and magnetism of μ-isophthalato dinuclear lanthanide(Ⅲ) complexes

Seven new μ-isophthalato dinuclear lanthanide(Ⅲ) complexes, namely [Ln2(IPHTA)(Me2-phen)4-(ClO4)2](ClO4)2 (Ln = La, Nd, Sm, Eu, Gd, Ho, Er), where Me2-phen denotes 2,9-dimethyl-1, 10-phenanthroline (Me2-phen) , IPHTA represents isophthalate dianion, have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, ESR and electronic spectra. The variable-temperature magnetic susceptibilities of [Gd2( IPHTA) (Mez-phen)4 (ClO4)2] (ClO4)2 complex were measured in the temperature range of 4-300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = - 2JS1 · S2, giving the exchange parameter J =- 0.19 cm-1 . This result is commensurate with a weak antiferromagnetic spin-exchange interaction between Gd(Ⅲ)-Gd(Ⅲ) ions within the complex.     

Synthesis and characterization of a tetranuclear copper(Ⅱ) complex with a chiral Schiff base ligand

The title complex l-[Cu^Ⅱ₄（Hvap）₂（vap）₂（MeOH）₂]（CIO₄）₂ 1 has been synthesized and characterized by EA. IR,TGA,solid-state CD spectra and X-ray single-crystal analyses（l-H₂vap’.a Schiff base ligand derived from the condensation of o-vanillin and l-2-amino-3-phenyl-l-propanol）.Complex 1 crystallizes in monoclinic system,chiral space group P2₁ with a =10.4257（18）.b = 21.695（4）,c = 15.721（3）A,β= 94.443（3）.V= 3545.1（11） ³,Z=2,Cu₄C₇₀H₇₈N₄O₂₂Cl₂.Mr= 1652.42,D_c= 1.548 g/cm³, F（000）= 1704 andμ（MoKα） = 1.338 mm^-1.The final R = 0.0682 and wR = 0.1420 for 6170 observed reflections with I > 2σ（I） and R = 0.1775 and wR = 0.1830 for all data.The structure of complex 1 contains a boat-shaped(Cu₄O₄} motif.The solid-state CD spectra confirm the chiral nature of complex 1.     

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     

Trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes bridged by μ_3-carbonato anion

The trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes [(CuTPA)_3(μ3-CO_3)] (ClO_4)_4(1) and [(ZnTPA)_3(μ_3-CO_3)] (ClO_4)_4 (2) (TPA=tri(pyridylmethyl) amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO_3~(2-) anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO_3_(2-) comes from atmospheric CO_2. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular bipyramidal environment. The [(CuTPA)_3 (μ_3-CO_3)] (ClO_4)_4 compound shows a very weak antiferromagnetic coupling.     

Synthesis, Crystal Structure and Ferromagnetic Properties of a New Dicyanamide Bridged Dicopper(Ⅱ) Complex with IM-1'-MeBzIm-κ2 N, O Mode

A new dinuclear copper(Ⅱ) complex with imino nitroxide radicals [Cu2(NO3)2(IM-1'-MeBzlm)2(dca)2] (IM-1'-MeBzlm = 2-{2'-[(1'-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimi-dazoline-1-oxyl, dca = dicyanamide anion) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinie, space group P1, with a =9.440(5), b = 10.124(6), c = 11.603(7)(A°), α= 102.904(7),β = 94.033(6), γ= 104.299(7)°,C34H40Cu2N16O8, Mr= 927.90, V= 1038.2(10) (A°)3, Z = 1, Dc=1.484 g/cm3,μ(MoKα) = 1.093 mm-1,F(000) = 478, R = 0.0609 and wR = 0.1512 for 2889 observed reflections with I > 2σ(I). X-ray analysis reveals that two Cu(Ⅱ) atoms are bridged by two dicyanamides to form a centrosymmetric Cu(Ⅱ)-Cu(Ⅱ) dinuclear entity. Every Cu(Ⅱ) ion is five-coordinated with a distorted square pyramidal coordination geometry and IM-1'-MeBzlm ligand coordinates to the metal ion with the κ2 N(1'-MeBzlm), O(IM) mode to avoid steric hindrance with the methyl group in the complex. Meanwhile, the molecules are linked by intermolecular hydrogen bonds, leading to a 1-D chain structure. Moreover, such chains are further linked by π-π stacking interactions to form a 2-D network structure. Magnetic measurement demonstrates that the intramolecular exchange couplings between Cu(Ⅱ) ion and the IM-1'-MeBzlm are ferromagnetic with J = 12.46 cm-1, where the spin Hamitonian is defined as H= -2JS1S2 within the complex.     

Synthesis and properties of the copper(Ⅱ) complexes with stable radical

Four novel copper(Ⅱ) complexes have been synthesized,namely Cu(hfac)2NITPhNO2 (1),Cu(hfac)2NITPhCH3 (2),Cu(pfpr)2NITPhNO2,(3) and Cu(Pfpr)2NITPhCH3 (4),where hfac= hexafluoro-acetylacetonate,pfpr=pentafluoropropionate,NITR.=2-R-4,4,5,5-tetraniethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.(R=4-nitrophenyl,4-methylphenyl).These complexes were rharicter-ized by elemental analyses,IR,electronic spectra and molar conductance.The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4 300 K range,giving I he exchange integral J=10.56 cm-1 for complex 1 and J =-30.9 cm-1 for complex 3.     

Synthesis,characterization and magnetism of copper(Ⅱ)-lan-thanide(Ⅲ) heterobimetalic complexes with N,N'-oxamidobis-(benzoato) cuprate (Ⅱ)

Seven new μ-oxamido copper(Ⅱ)-lanthanide(Ⅲ)hetero-bitnetalic complexes described by the fonnula Cu(obbz)Ln-(Ph-phen)2NO3(Ln=La,Nd,Eu,Gd,Tb,Ho,Er),where obbz denotes the oxamidobis(benzoato)and Ph-phen represents 5-phenyl-1,10-phenanthroline,have been synthesized and characterized by the elemental analyses,spectro-scopic(IR,UV,ESR)studies,magnetic moments(at room temperature)and molar conductivity measurement.The temperature dependence of the magnetic susceptibility of Cu(obbz)Gd(Ph-phen)2NO3 complex has been measured over the range 4.2-300 K.The least-squares fit of the experimental susceptibilities based on the spin Hamiltonian operator,H=-2JS1 S2,yielded J= 1.28 cm-1,a weak ferromagnetic coupling.A plausible mechanism for a ferromagnetic coupling between Gd(Ⅲ)-Cu(Ⅱ)is discussed in terms of spin-polarization.     

Synthesis and molecular modeling study of Cu(Ⅱ) complexes derived from 2-(diphenylmethylene)hydrazinecarbothioamide derivatives with cholinesterase inhibitory activities

Thiosemicarbazones of 2-amino-5-chlorobenzophenone and 3-aminobenzophenone（L¹-L⁴） have been synthesized and their Cu（Ⅱ） complexes（1-4） were afforded via coordination with cupric chloride.All these compounds were characterized by UV-vis and IR spectroscopy together with CHN elemental analysis.NMR spectroscopy was also applied to characterize the ligands.In vitro chohnesterase inhibitory assays for the complexes（1-4） showed IC₅₀ values less than 10μmol/L,with complex 1 exhibiting the most activity,IC₅₀=2.15μmol/L and 2.16μmol/L for AChE and BuChE,respectively. Molecular modeling simulation revealed the binding interaction template for complex 1 with the AChE and BuChE receptors.In DPPH assay,the complexes also showed more in vitro antioxidant activities in comparison to their parent ligands.     

Synthesis, characterization and magnetic properties of novel μ-isophthalato oxovanadium(IV) binuclear complexes

Four novel oxovanadium(IV) binuclear complexes have been synthesized, namely [(VO)₂(IPHTA) (L)₂SO₄ (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me₂bpy) and 5-nitro-1,10-phenanthroline (NO₂-phen)), where IPHTA is the isophthalate dianon. Based on elemental analyses, molar conductivity measurements, IR and electronic spectra studies, it is proposed that these complexes have IPHTA-bridged structures and consist of two vanadium(IV) atoms in a square-pyramidal environment. The complexes [(VO)₂(IPHTA)(Me₂bpy)₂]SO₄ (1) and [(VO)₂(IPHTA)(bpy)₂]SO₄ (2) were characterized by variable temperature magnetic susceptibility (4–300 K) and the data could be well fitted by the least-squares method to a susceptibility equation derived from the spin Hamiltonian operator, . The exchange integral, J, was found to be −26.8 cm⁻¹ for (1) and −31.0 cm⁻¹ for (2). These results are commensurate with antifferomagnetic interactions between two oxovanadium(IV) ions within each molecule. The influence of different terminal ligands on magnetic interactions between the metals of this kind of complexes is also discussed.     

Synthesis characterization and magnetic properties of μ-iodanilato dinuclear oxovanadium(IV) complexes

Five oxovanadium(IV) dinuclear complexes described by the overall formula [(VO)₂(IA)L₂SO₄, where IA repents the dianion of iodanilic acid and L denotes 2, 2′-bipyridine (bpy); 4,4′-dimethy12,2′-bipyridine (Meo-bpy); 1,10-phenanthroline (phen); 4,7-diphenyl-l, 10-phenanthroline (Ph₂-phen) and 5-nitro-1, 10-phenanthroline (NO₂-phen), have been synthesized and characterized by elemental analyses, molar conductivity and roomtemperature magnetic moment measurements, IR and electronic spectral studies. It is proposed that these complexes have IA-bridged structures and consist of two oxovanadium(IV) ions each in a square pyramidal environment. The complexes (VO)₂(IA) (bpy)₂]SO₄, (1) and[(VO)₂( IA) (phen)₂ ]SO₄ (2) were further characterized by variable temperature (4.2–300 K) magnetic susceptibility measurements and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method, giving the exchange integral J = - 2.15 m^?1 for 1 and J = - 9.88 cm^?1 for 2. This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VO²⁺ ions within each molecule.     

Synthesis and X-ray crystal structure of oxamido-bridged heterobinuclear Ni(Ⅱ)-Cu(Ⅱ) complexes

The two complexes [Ni(oxen)Cu(L)2](ClO4)2.xH2O (L=2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen)) have been synthesized, where oxen is N,N'-bis(2-aminoethyl)oxamido di-anion. The crystal structure of [Ni(oxen)Cu(bpy)2](ClO4)2.CH3OH has been determined by X-ray diffraction method. The crystal is triclinic system, space group P1 with a=12.179(1),b=12.298(2), c=11.476(2) A, a=97.57(1), B=97.52(1), 7=80.29(2), V=1669.04(67) A3, Z=2, Dcalcd=1.667 g/cm3. The structure has been refined to final R of 0.076 and Rw of 0.080, respectively. The complexes have an extended oxamido-bridged structure and consist of Ni(Ⅱ) ion in a square planar environment and Cu(Ⅱ) ion in a distorted octahedral environment.     

Synthesis and magnetism of μ-isophthalato dinuclear lanthanide(III) complexes

Seven new μ-isophthalato dinuclear lanthanide(III) complexes, namely [Ln₂(IPHTA)(Me₂-phen)₄-(ClO₄)₂](ClO₄)₂ (Ln=La, Nd, Sm, Eu, Gd, Ho, Er), where Me₂-phen denotes 2,9-dimethyl-1,10-phenanthroline (Me₂-phen), IPHTA represents isophthalate dianion, have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, ESR and electronic spectra. The variable-temperature magnetic susceptibilities of [ Gd₂ (IPHTA) (Me₂-phen)₄ ( ClO₄ )₂ ] ((ClO₄ )₂ complex were measured in the temperature range of 4–300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = -2JS₁. J₂. giving the exchange parameter J = -0.19 cm^?1. This result is commensurate with a weak antiferromagnetic spin-exchange interaction between Gd(III)-Gd(III) im within the complex.     

Synthesis and Magnetic Studies of Copper (II)‐Manganese (II) Heterobinuclear Complexes with an Oxamido Bridge

Four new copper (II)‐manganese (II) heterobinuclear complexes bridged byN, N'‐bis[2‐(dimethylamino)ethyl)]oxamido dianion (dmoxæ) and end‐capped with 1, 10‐phenanthroline (phen), 5‐methyl‐1, 10‐phenanthroline (Mephen), diaminoethane (en) or 1,3‐di‐aminopropane (pn). respectively, namely, [Cu(dmoxae)MnL₂] (CIO₄)₂ (L=phen, Mephen, en, pn), have been synthesized and characterized by elemental analyses, IR, electronic spectral studies, and molar conductivity measurements. The electronic reflectance spectrum indicates the presence of spin exchange‐coupling interaction between bridged copper(II) and manganese (II) ions. The cryomagnetic measurements (4.2‐300 K) of [Cu(dmoxae)Mn(phen)₂](CIO₄)₂ (1) and [Cu(dmoxae)Mn(Mephen)₂](CIO₄)₂(2) complexes demonstrated an antiferromagnetic interaction between the adjacent manganese(II) and copper (II) ions through the oxamido‐bridge within each molecule. On the basis of spin Hamiltonian, H= ‐ 2JS₁. S₂. the magnetic analysis was carried out for the two complexes and the spin‐coupling constant (J) was evaluated as ?35.9 cm^?1 for 1 and ‐ 32.6 cm^?1 for 2. The influence of methyl substitutions in the amine groups of the bridging ligand on magnetic interactions between the metal ions of this kind of complexes is also discussed.     

Synthesis and magnetic properties of copper (II)-lanthanoid (III) binuclear complexes with N,N′-bis(3-aminopropyl) oxamido ligand

Six novel μ-oxamido binuclear complexes, namely Cu(axpn)Ln(L)₂(ClO₄)₃ (Ln: Eu, Gd, Tb, Nd, Ho, Er), where oxpn is N,N'-bis(3-aminopropyl) oxamido, L denotes 5-nitro,10-phenanthroline (abbreviated as NO₂-phen), have been synthesized and characterised. The magnetic susceptibility of complexes Cu(oxpn)Gd(NO₂-phen)2(ClO₄)₃.2H₂O was measured over the 4–300 K and the observed data were successfully simulated by equation based on spin Hamiltonian operator (H = -2J₁ · S₂), giving the exchange integral J(Cu-Gd)=-1.62 cm^?1. This indicates a weak antiferromagnetic interaction between the Cu(II) and Gd(III) ions.     

Synthesis and ferromagnetic interaction in oxamido-bridged heterodinuclear copper(II)-chromium (III) complexes

Four μ- oxamido heterodinuclear complexes, [Cu (oxae) Cr (L)₂ ] (NO₃) ₃, where oxae denotes the N, N'bis (2-aminoethyl) oxamido dianion and L represents 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO_2-phen); 5-methyl-1, 10-phenanthroline (Me-phen) and 2, 2′-bipyridine (bpy), have been synthesized and characterized by elemental analyses, magnetic moments (at room temperature) and molar conductivity measurements and spectroscopy. It is proposed that these complexes have extended oxamido-bridged structures consisting of a copper (II) ion and a chromium (III) ion, which have a square planar environment and octahedral environment, respectively. The cryomagnetic properties of the [Cu(oxae)Cr(bpy)₂(NO₃)₃(1) and [Cu(oxae)Cr(phen)₂](NO₃)₃(2) complexes have been measured over the range of 4.2–300 K. The leastsquares fit of the experimental data based on the spin Hamiltonian, ? = - 2J?₁·?₂, the exchange integrals (J) were evaluated as +36.9 cm^?1 for 1 and +35.8 cm^?1 for 2. The reds have connived that the spin coupling between the adjacent copper (II) and chromium (III) ions through oxamido-bridge in both 1 and 2 is ferromagnetic.     

Synthesis,Characterization and Crystal Structure of （2,2′—Bipyridine）（μ—maleato）copper（Ⅱ）Dihydrate

The title polymeric complex [Cu(C₄H₂O₄)(C₁₀H₈N₂)]_n·2nH₂O was prepared and its crystal structure was determined by X‐ray diffraction methods. The crystal belongs to space group P2₁/c with cell dimensions of a = 1.0104(1), b = 1.9952(2), c = 0.7357(2) nm, β= 98.38(2)° and Z = 4. The complex forms zig‐zag chains along crystallographic axis c via Cu—O (carboxyl) bond in the apical direction. Each repeated unit consists of a square pyramidal Cu(II) centre with one maleate dianion and one 2,2′‐bipyridine forming a basal plane. Adjacent chains link to each other by H‐bonding between carboxyl groups and crystalline water. The distance of 0.3482 nm between parallel bipyridine rings shows a π‐π stacking interaction. The title complex was also characterized by IR, UV and ESR spectra.     

Synthesis,structure and characterization of copper(II) and zinc(II) complexes based on 3-carboxyl-1,2,4-triazole

Two complexes [CuL₂(H₂O)₂] (1) and [ZnL₂(H₂O)₂] (2) (L?=?3-carboxyl-1,2,4-triazole (L)) have been synthesized and characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/n, a?=?8.632(8)?Å, b?=?9.153(8)?Å, c?=?6.991(7)?Å, β?=?94.279(12)°, Z?=?2, R ₁?=?0.0296, wR ₂?=?0.0918. Compound 2 also crystallizes in the monoclinic space group P ₂(1)/n, a?=?4.937(3)?Å, b?=?18.107(10)?Å, c?=?6.344(4)?Å, β?=?106.839(7)°, Z?=?2, R ₁?=?0.0230, wR ₂?=?0.0556. Extensive intermolecular hydrogen bonds assemble 1 and 2 into three-dimensional (3D) supramolecular architectures, with eight-member H-bonded synthons. Compounds 1 and 2 were also characterized by element analysis, FT–IR, luminescence and EPR studies.