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

Six novel u-oxamido binuclear complexes, namely Cu(oxpn)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-1,10-phenanthroline (abbreviated as NO2-phen), have been synthesized and characterized. 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 Hamil-tonian operator (H = -2JS1.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 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 magnetic properties of binuclear cobalt(Ⅱ), nickel(Ⅱ) and copper(Ⅱ) complexes bridged by oxamidate group

Four binuclear Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(ClO4)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2.H2O (2), Ni2(bpy)2(oxd)(ClO4)2.2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2'-bipyridyl, Me2-bpy=4,4'-dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable-temperature magnetic susceptibility (4-300 K). The susceptibility data for. complexes 1 and 3 were least-squares fit to the susceptibility equation derived from the spin Hamiltonian H=-2J . S1 . S2. The exchange integral, J, was found to be equal to -3.62 cm-1 in 1 and -1.82 cm-1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal 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 (NO2-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 least-squares fit of the experimental data based on the spin Hamiltonian, H = - 2JS1·S2, the exchange integrals (J) were evaluated as 36.9 cm-1 for 1 and 35.8 cm-1 for 2. The results have confirmed     

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.     

Di- and tetranuclear heterometallic CuII-LnIII complexes (Ln = Gd and Dy): Synthesis, structure and magnetic properties

Four 3d-4f heterometallic complexes, [CuⅡ LnⅢ (bpt) 2 (NO 3 ) 3 (MeOH)] (Ln = Gd, 1; Dy, 2; bptH = 3,5-bis(pyrid-2-yl)-1,2,4- triazole), [CuⅡ 2 LnⅢ 2 (μ-OH) 2 (bpt) 4 Cl 4 (H 2 O) 2 ]·6H 2 O (Ln = Gd, 3; Dy, 4), have been synthesized under solvothermal conditions. X-ray structural analyses reveal that 1 and 2 are isostructural while 3 and 4 are isostructural. In each complex, the copper and gadolinium or dysprosium ions are linked by two triazolate bridges and form a CuⅡ -LnⅢ dinuclear unit. The intramolecular Cu-Ln distances are 4.542, 4.525, 4.545 and 4.538 for 1, 2, 3 and 4, respectively. Two dinuclear CuLn units are bridged by two OH- groups into the zig-zag tetranuclear {CuⅡ 2 LnⅢ 2 } structures with the Ln(Ⅲ) Ln(Ⅲ) distances of 3.742 and 3.684 for 3 and 4, respectively. Magnetic studies show that the antiferromagnetic CuⅡ-LnⅢ interactions occur in 1 (J CuGd = 0.21 cm-1 ) and 2. The antiferromagnetic interaction occurs in complex 3 with J CuGd = 0.82 cm-1 and J GdGd = 0.065 cm-1 , while dominant ferromagnetic interaction occurs in complex 4.     

Synthesis,structures and magnetic properties of a series of polynuclear copper(Ⅱ)-lanthanide(Ⅲ) complexes assembled with carboxylate and hydroxide ligands

Heterometallic copper(Ⅱ)-lanthanide(Ⅲ) complexes have been made with a variety of exclusively O-donor ligands including betaines (zwitterionic carboxylates) and chloroac-etate,which are dinuclear CuLn,tetranuclear Cu2Ln2,pen-tanuclear Cu2Ln2,and octadecanuclear Cu12Ln6 complexes.Hie results show that subtle changes in both the carboxylates and acidity of the reaction solution can cause drastic changes in the structures of the products.Magnetic studies exhibit that shielding of the Ln3 4f electrons by the outer shell electrons is very effective to preclude significant coupling interaction between the Ln3 4f electrons and Cu2 3d electrons in either a mono-atomic hydroxide-bridged,or a carboxylate-bridged system.     

Synthesis and characterization of novel heteronuclear complexes of Ln(Ⅲ)-Cu(Ⅱ) with non-cyclic polyether Schiff base

Nine novel heteronuclear complexes of Ln(Ⅲ)-Cu(Ⅱ) with salicylidene tetraethvlcne glycol diamine (SALTTA) have been synthesized and characterized.They have the general formulae [LnCu2(SALTTA)2(NO3)3](NO3)4 3H2O (Ln=La,Pr.Nd,Srn) and [LnCu3(SALTTA)3(NO3)5]-(NO3)4-4H2O (Ln=Gd,Tb,Er,Yb,Y).The IR spectra show that vc=N in the Ln(Ⅲ)-Cu(Ⅱ) het-eronuclear complexes are splitted up into two peaks with a far distance.It has been confirmed that oxygen atoms in oxyethylene of the ligand are not all coordinated to the central metal ions by both IR and NMR methods.     

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 catalytic activity of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base

A series of novel heteronuclear Ln(Ⅲ)-Cu(Ⅱ) complexes with noncyclic polyether-amino acid Schiff base were synthesized. The general formula is [LnCu_2(H_2TALY)(NO_3)_5](NO_3)_2' nH_2O(Ln=La, Nd, Sm, Gd, n= 4; Ln=Yb, Y, n=3), where H_2TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(Ⅱ) complexes and Ln(Ⅲ)-Cu(Ⅱ) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra, TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained may be used as a catalyst, which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes with such aliphatic Schiff bas     

Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M =Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

A series of 1D nickel(Ⅱ)/zinc(Ⅱ)-lanthanide(Ⅲ) coordination polymers, [M(μ-L)2Ln(NO3)3]n· solvents (HL =bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1 · NiGd), Tb (2· NiTb), Dy (3· NiDy), Ho (4· NiHo), Y (5· NiY);M = Zn, Ln =Gd (6· ZnGd), Tb (7· ZnTb), Dy (8· ZnDy), Ho (9· ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1-9, where weak ferromagnetic interaction is found in 1 · NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4· NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.     

Synthesis and magnetism of rare earth (Nd,Gd,Dy,Ho,Er,Y) pentafluoropropionate binuclear complexes with 2-(4''''-methoxy-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide

Six compounds of the general formula [Ln(pfpr)3]2(NITPhOMe).nH2O, where Ln=Nd, Gd, Dy, Ho, Er, Y, pfpr=pentafluoropropionate, NITPhOMe=2-(4'-methoxyphenyl)-4,4,5, 5-tetra-methylimidazoline-1-oxyl-3-oxide, and n=4 (for Nd, Dy, Er); 3 (for Gd); 6 (for Ho); 5 (for Y), have been synthesized. These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductances. The variable temperature (4-300 K) magnetic susceptibility of the complex [Gd(pfpr)3]2(NITPhOMe).3H2O was determined. The observed susceptibility data were fit to those from theoretical magnetic equation by least-squares method. The exchange integral, J, was found to be equal to 2.14 cm-1. This indicates a weak ferromagnetic spin-exchange interaction between the radical and the gadolinium(III) ion.     

Structure and magnetostructural correlation of ferrimagnetic meso-tetraphenylporphinatomanganese(III) dimethyl-N,N′-dicyanoquinone diiminide, [MnTPP]+[Me2DCNQI]·?

The structure [MnⅢ TPP][Me2 DCNQI] (TPP = tetraphenylporphinato; Me 2 DCNQI = 2,5-dimethyl-N,N′-dicyanoquinonediimine) has been determined from X-ray powder diffraction data. The nonsolvated structure is composed of linear (1-D) chains of alternating [MnⅢ TPP] + and μ-[Me 2 DCNQI] with intrachain Mn···Mn separations of 12.83 , and a Mn N DCNQI distance of 2.18. The dihedral angle between the mean Mn(N 4 ) TPP and [Me 2 DCNQI].- planes, and the Mn (N C) DCNQI angle are 84.18° and 143.6°, respectively. [MnⅢ TPP][Me 2 DCNQI] has a T c of 4.3 K from the 10 Hz χ"(T) data, 2-K coercivity of 5,600 Oe, and 6,300 emuOe/mol remnant magnetization that are reduced from that observed for related materials, and their inclusion extends the magnetostructural correlation between the intrachain coupling and both the dihedral angle between the mean Mn(N 4 ) TPP and [TCNE]*- (TCNE = tetracyanoethylene) planes and Mn (N C) TCNE angles. This is in accord with the intrachain coupling arising from the overlap of the MnⅢ d z 2 -like singly occupied molecular orbital (SOMO) and the z component of the [TCNE]*-π* (πz *) SOMO, which increases with decreasing dihedral angle between the mean Mn(N 4 ) TPP and [TCNE]*- planes and Mn (N C) TCNE angle.     

Synthesis and Properties of u-Oxamido Heterobinuclear Cu(Ⅱ)-Co(Ⅱ) Complexes

Three heterobinuclear complexes were synthesized, namely [Cu (oxpn) Co (L)2] (ClO4)2·xH2O(L= 2,2'-bipyridyl(bpy), 1,10-phenanthroline(phen) , and 5-nitro-1, 10-phenanthroline (NO2-phen)), where oxpn represents N, N'-bis(3-aminopropyl) oxam-ido. Based on 1R, elemental analysis, conductivity measurement and electronic spectra, these complexes were characterized by an extended oxamido-bridged structure with Cu(Ⅱ) in a planar environment and Co(Ⅱ) in a octahedral environment. The symmetry of the cation is very close to C2v.The complexes were also characterized with variable temperature (4~300K) magnetic susceptibility, and the data were fit for the susceptibility equation derived from spin Hamilton, H= -2JS1.S2-DSx12 by least square strategy. The exchange integral, J, was found to be -22.36 cm-1 (for bpy);-15.45 cm-1 (for phen); -19. 10cm-1(for NO2-phen), indicating that there is a weak antiferromagnetic spin-exchange interaction between the metal ions.     

Structure and magnetic properties of homobinuclear gadolinium (Ⅲ) complex of isonicotinoyl hydrazone

The crystal structure of [Gd2(μ-L)3(H2O)2].1.5(NO3).1.5 (OH)-5H2O (where L is an-ion of N, N'-Diisonicotinoyl-2-hydroxy-5-methyl-isophthalaIdehyde dihydrazone) has been determined by X-ray diffraction method. The complex crystallizes in the monoclinic system, space group P21/c with a=1.6654(3), b=1.6904(3), c=2.8039(6) nmβ=91.30(3)°, final R factor is 6.3%. The structrue consists of [Gd2(μ-L)3(H2O)2]3+ cation, one and a half nitrate and 1.5 hydroxyl anions and five water molecules. Within dinuclear cation, Gd(Ⅲ)-Gd(Ⅲ) is bridged by oxygen and nitrogen atoms of the three ligands, resulting in Gd...Gd distance of 0.36353(2) nm. Gd(Ⅲ) exhibits a distorted 1333 stack coordination environment. Magnetic susceptibility measurements in the temperature range 300-4 K revealed the occurrence of weak antiferromagnetic exchange interaction between two Gd(Ⅲ) ions with a J value of -0.22, and g of 1.93.     

Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers constructed from quinolinic acid and nicotinic acid: Synthesis, structures, and magnetic properties

Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers based on two N-heterocyclic carboxylic ligands, {[LnCu(L1)2(L2)(H2O)2]·mH2O}n (Ln = La(1), Nd(2), Gd(3), m = 2 (for 1), 1 (for 2, 3), H2L1 = quinolinic acid, HL2 = nicotinic acid), have been synthesized and characterized. 1 has a two-dimensional (2D) layer structure with a Schlfli symbol of (44.62), while complexes 2 and 3 are isostructural and have three-dimensional (3D) structures with a Schlfli symbol of (3.4.5)2(32.42.52.614.74.83.9)(32.63.7) of 3-nodal net. Magnetic investigations suggest that antiferromagnetic coupling exists between NdIII and CuII in 2, while weak ferromagnetic coupling between GdIII and CuII in 3. The difference of magnetic properties between 2 and 3 has been discussed.     

Two New Copper(Ⅱ) Complexes with p-Cyanobenzoic Acid: Synthesis,Crystal Structures and Properties

The complexes of [Cu(bpy)(H2O)(CBA)2]n 1 and [Cu(phen)(H2O)(CBA)2]·H2O 2 based on p-cyanobenzoic acid(HCBA) have been synthesized in aqueous ethanolic solution at room temperature. The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in orthorhombic and complex 2 is of triclinic system. The results indicate the complex 1 shows a 1D chain structure bridged by two carboxylic oxygen atoms from CBA–, and complex 2 is a mononuclear structure. Through intermolecular hydrogen bonding and π...π stacking interactions, the complexes are assembled into supramolecular structures. Complex 1 has been characterized by magnetic measurements. The magnetic measurement indicates that weak ferromagnetic interaction(zJ= 0.038(5)) between the Cu2+ ions is dominant in the structure. The IR spectrum and results of thermal and elemental analyses are also presented.     

SYNTHESIS AND CRYSTAL STRUCTURE OFμ-TEREPHTHALATO BINUCLEAR COBALT(Ⅱ) COMPLEX [Co_2(tpha)(bpy)_4](ClO_4)_2

<正> The structure of μ-terephthalato binuclear cobalt (Ⅱ) complex CCo2(tpha)(bpy)4](ClO4)2(tpha=μ-terephthalato, bpy=2,2' -bipyridine) has been determined by X-ray method. Crystals of title complex are monoelinic, space group P21/c, with a = 13. 086(2), b = 9. 428(2), c=20. 237(4) A. β= 108. 83(1)°, Mr = 1105.61, Z = 2, Dx = 1. 55g/cm3, μ= 8. 09cm-1 and F(000)= 1128. The structure has been solved by direct methods and refined to R=0. 053, The title cation has Ct symmetry in which the terephthalato group acts as bridging ligand between the two metal atoms. Each cobalt(Ⅱ)ion is in a distorted octahedral environment. The Co.....Co distance is 10. 35A.     

Studies on synthesis and magnetic resonance of lanthanide complexes with novel Schiff base derived from noncyclic polyether and P-diketone

Nine Ln( Ⅲ ) complexes with a novel Schiff base derived from diglycolamine and benzoylacetone (BZDA) have been synthesized and characterized. They can be formulated as [Ln2(BZDA)3(NO3)3](NO3)3· nH2O(Ln=La, Pr, Nd, Sm, n = 4; Ln=Gd, Tb, Er, Yb, Y, n = l). Enamic form mechanism in this β-diketone Schiff base and its complexes were suggested and proved by IR, UV and NMR methods. The 13C spin-lattice relaxation time T1 and the ratios of r(ci-Ln)/r(cj-Ln) were measured by a 500 MHz NMR instrument for elucidating the formation of the stable sk-membered chelate ring structure in these complexes. The EPR spectrum of the Gd( Ⅲ ) complex exhibits the "U" spectral feature and "zero field effect". On the basis of them, the crystal field strength and the local symmetry around Gd3 in the complex have been discussed.