Synthesis and Magnetism of μ-IsophthalatoOxovanadium(Ⅱ) Binuclear Complexes

Two μ-isophthalato oxovanadium(Ⅱ) binuclear complexes, [(VO)2-(IPHTA) (phen)2] SO4 (1) and [(VO)2 (IPHTA) (NO2-phen)2 ]SO4 (2) were syn thesized and characterized. The magnetism of complex (1) was studied

Synthesis and Characterization of Binuclear Lanthanide Complexes with Macrocyclic Schiff Base Derived From 2,6-Diacetylpyridine and 1,3-Diamino-2-hydroxypropane

Nine homobinuclear lanthanide complexes with macrocyclic Schiff base were prepared by condensing 2, 6-diacetylpyridine and 1, 3-diamino-2-hydroxypropane in the presence of template lanthanide metal ions. These complexes were characterized by elemental analysis, IR, molar conductance and magnetic susceptibility. The variable-temperature magnetic susceptibility (4-300 K) of complexes of Gd( Ⅲ ) and Dy( Ⅲ ) was determined. A satisfactory fit to theoretical curve derived from spin Hamiltonian operator was obtained using least-squares method. The exchange interaction parameters are J=-0.26 cm-1, g=1.98 and △=0.06 cm-1, Z.J'=-0. 21 cm-1,g'=1.33 for Gd( Ⅲ ) and Dy( Ⅲ ), respectively. The results indicate a very week antiferromagnetic interaction between Gd( Ⅲ )-Gd( Ⅲ ) and Dy( Ⅲ )-Dy( Ⅲ ) ions.

Syntheses and Magnetism of Binuclear Tb(Ⅲ)-Tb(Ⅲ)Complexes with Dianion of Chloranilic Acid as Bridging Ligand

The syntheses, spec(?) complexes are of significance for understanding mechanisms of magnetic interaction between metal ions and the exploitation of the synthesis of molecular magnetic materials. There were a few works reported previously on the syntheses and magnetic in-

Synthesis,structures,thermal and magnetic properties of a series of lanthanide Ln=Sm,Gd,Er,Yb complexes with 4-quinolineacarboxylate

A series of lanthanide binuclear complexes, Ln2（L）6（H2O）4·2H2O（Ln=Sm（Ⅲ）, Gd（Ⅲ）, Er（Ⅲ）, Yb（Ⅲ）, HL=4-quinolinea-carboxylic acid, were synthesized by reactions of corresponding rare earth salts with 4-quinolineacarboxylic acid at room temperature and were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction.X-ray diffraction analyses showed that they exhibited the same binuclear architecture and crystallized in monoclinic system and P21/c space group.In four complexes, each metal center adopted nine-coordinated mode coordinated by nine O atoms from two H2O molecules and three carboxyls of three ligands, and HL showed three different coordination modes.The variable-temperature magnetic susceptibility showed that complex Gd2（L）6（H2O）4·2H2O performed very weak antiferromagnetic property at low temperature and exchange was almost paramagnetic at high temperature.Complexes Er2（L）6（H2O）4·2H2O and Yb2（L）6（H2O）4·2H2O performed dominating antiferromagnetic coupling.

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.

Syntheses, Crystal Structures and Magnetic Properties of Two Lanthanide Mononuclear Complexes

Two isostructural lanthanide complexes, [Tb(salen)2]3·3C2H9N2·4CH4O(1) and [Er(salen)2]3·3C2H9N2·2CH4O(2), where H2 salen = N,N'-bis(3-methoxysalicylidene)ethylene-1,2-diamine, have been in situ synthesized under solvothermal conditions and characterized by IR, elemental analysis, powder and single-crystal X-ray diffraction analysis, and magnetic analysis. Single-crystal X-ray diffraction indicates that the complexes crystallize in monoclinic C121 space group. Each lanthanide center is coordinated with four oxygen and four nitrogen atoms from two salen^2- ligands, forming distorted square antiprism geometry. Both 1 and 2 exhibit obvious slow magnetization relaxation under an applied 2 kOe magnetic field.

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 Two Binuclear Macrocyclic Zinc(Ⅱ) Complexes by Anion Exchange

Two macrocyclic zinc（Ⅱ） complexes {[ZnL（VO3）2]·0.33H2O}n（1） and [ZnL（H2O）2][Ni（CN）4]（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane） have been obtained from the reactions of [ZnL]（ClO4）2 with NH4VO3 and K2[Ni（CN）4], respectively, and structurally characterized by elemental analysis, IR, XRPD, TG and X-ray diffraction. Single-crystal X-ray diffraction analyses indicated that the Zn（Ⅱ） atom lies on an inversion center and is octahedrally coordinated by four nitrogen atoms of the tetradentate macrocyclic ligand in the equatorial plane and two oxygen atoms of [VO4] tetrahedra in the axial positions in 1, and two oxygen atoms of two water molecules in 2. Complex 1 shows a three-dimensional structure, which is constructed by the links of [VO3]nn- chains with [ZnL]2＋, forming one-dimensional channels occupied by guest water molecules. The monomers of [ZnL（H2O）2]2＋ and [Ni（CN）4]2- are connected through the intermolecular hydrogen bonds to form a two-dimensional sheet in complex 2.

SYNTHESIS AND CHARACTERISTICS OF HOMOBINUCLEAR MACROCYCLIC COMPLEXES OF RARE EARTH METAL ISOTHIOCYANATE AND PHENOLIC SCHIFF BASES

Eleven homobinuclear macrocyclic rare earth metal ions complexes are obtained as com-pounds of 2:2 Schiff base formed by condensing 2,6-diformyl-4-tert-Butylphenol and triethy-lenetetramine by a template procedure using rare earth metal isothiocyanates. These complexesare characterized by elemental analyses, FABMS, IR, conductivity and magnetic susceptibility.The variable-temperature magnetic susceptibility (4--300K) of complexes of Gd(Ⅲ) and Tb(Ⅲ) has been determined. A satisfactory fit to theoretical curve derived from spin Hamil-tonian operator was obtained by least squares method. The exchange interaction parameters areJ =-0.220 cm^(-1) for Gd, ,ZJ~?=-0.052 cm^(-1) for Tb. The results indicate a very weak anti-ferromagnetic interaction between Gd^(3+)-Gd^(3+), Tb^(3+)-Tb^(3+) ions.

Crystal structure and magnetism of the binuclear Gd(Ⅲ) complex Gd_2(C_12H_8N_2)_2(C_6H_5COO)_6

In the medium of H2O, C2H5OH and HAC, the reaction of Gd(NO3)3-6H2O with C6H5COONa and C12H8N2 produced a novel binuclear Gd(Ⅲ) complex in formula [Gd2(C12H8N2)2 (C6H5COO)6]. Crystallographic data: crystal system, triclinic; space group, P l ; unit celi dimensions, α=1.191 9(2) nm, b =1.244 2(2) nm, c = 1.080 4(2) nm, α = 93.57(3)°, β= 113.33(3)°, y= 105.06(3)°, Z =1. The final R = 0.037 6. The magnetic measurement of the crystal powder in the temperature region of l .5-300 K shows that this complex possesses antifer- romagnetic property with fitting magnetic parameters .J = -0.471 and g =1.975.

SYNTHESIS, STRUCTURE AND MAGNETISM OF μ-OXAMIDO BINUCLEAR COPPER(Ⅱ) COMPLEXES

<正> Two new binuclear copper（Ⅱ） complexes, [Cu（oxpn）CuL]（ClO4）2, have been synthesizedand characterized, where oxpn is N,N’ bis（3-aminopropyl）oxamido and L is 1,10-phenan-throline （phen） or 5-nitro-1,10-phenanthroline （NO2-phen）. The crystal structure and vari-able-temperature magnetic susceptibility （4- 300 K） of the Complex （L=phen） have beendetermined. Crystal data: orthorhombic system, space group Pnma, with a = 10.433（1）, b11.458（2）, c = 21.999（2）A, z = 4. Every copper（Ⅱ） ion is in a square pyramidal environment.The two copper（Ⅱ） ions are linked by μ-oxamido bridge and the separation of them is 5.208A. The singlet-triplet energy gap J was found equal to -452.92cm-1, indicating that astrongantiferromagnetic spin-exchange interaction operates between the copper（Ⅱ） ions.

Syntheses and Crystal Structures of Lanthanide Complexes of New 15-Membered Macrocyclic Ligands with Three Pendant Acetato Groups

Two new 15-membered functionalized macrocycles, dioxo^polyazacycloalkanes with three pendant acetato groups, have been synthesized by the condensation reaction of DTPA dianhydride (DTPA=diethylenetriaminepentaacetic acid) with 1,2-diaminopropane, (15-DTPA-1,2-pn), or 1,2-diaminocyclohexane, (15-DTPA-1,2-cy). Their lanthanide complexes [Ln(15-DTPA-1,2-pn)(H 2O)] 2 [Ln=Eu (1), Gd (2)] and [Ln(15-DTPA-1,2-cy)(H 2O)] 2 [Ln=Eu (3), Gd (4)] were also prepared. Single crystal X-ray diffraction analyses of complexes 2 and 4 show that they have dimeric structures in solid state; each metal ion is nine-coordinated in a distorted tricapped-trigonal prism. In complex 4, the coexistence of two diastereoisomeric molecules in the crystal lattice was observed.

SYNTHESIS AND MAGNETISM OF BINUCLEAR COPPER(Ⅱ) COMPLEXES CONTAINING SALUCYLAMIDATOCUPRATE(Ⅱ)

<正> New binuclear copper（Ⅱ） complexes, [Cu（samen）Cu（NO2-phen）]·H2O and [Cu（sampn）-Cu（NO2-phen）]·2H2O have been synthesized, where samen4-, sampn4-and NO2-phen denote N, N′-ethylenedisalicylamidate anion, N, N′-1, 2-propanedisalicylamidate anion and 5-nitro-1, 10-phenanthroline respectively. 3ased on IR, elemental analyses and electronic spectra, the complexes are proposed to have a phenoxy-bridged structure and to consist of the Cu（Ⅱ）ion in distorted planar environment. The complexes have been characterized with varlable-temperature magnetic susceptibility （4—300 K） and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral J=-63.0 cm-1（samen） and J=-46.5cm-1（sampn）. This indicates the existence of antiferromagnetic spin exchange interaction among the metal ions.

Synthesis, characterization and magnetism of binuclear cobalt (II) complexes bridged by tetracarboxylato groups

Three new binuclear cobalt (II) complexes with extended tetracarboxylato-bridge have been synthesized and characterized, namely [Co2 (PMTA) (bpy)4] (1), [Co2(PMTA)-(phen)4] (2) and [Co2(PMTA)(NO2phen)4 (3), where PMTA represents the tetraanion of pyromellitic acid, and bpy, phen, NO2-phen denote 2,2-bipyridine, 1,10-phenanthroline; 5-nitro-1, 10-phenanthroline, respectively. Based on elemental analyses, molar conductivity measurements, IR and electronic spectra studies, it is proposed that these complexes have PMTA-bridged structures and consist of two cobalt(II) ions, each in a distorted octahedral environment. These complexes were further characterized by variable temperature magnetic susceptibility measurements (4–300 K) and the observed data were successfully simulated by th e equation based on the spin Hamiltonian operator, ?=?2J ?1·?2, giving the exchange integral J= ?1.02 cm?1 for 1, J= ?1.21 cm?1 for 2 and J = ?1.18 cm?1 for 3, respectively. These results revealed the operation of antiferromagnetic spin-exchange interaction between the two Co(II) ions within each molecule.

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 magnetic properties of μ-phenolato copper (Ⅱ) binuclear complexes with different exogenous bridges

The syntheses and magnetic properties are reported for a series of copper(Ⅱ) complexes prepared from a pentadentate binucleating ligand 2,6-diformyl-4-methylphenol di(benzoyl-hydrazone) (H3L). These complexes incorporate different exogenous ions (X-) into a bridging position to form copper(Ⅱ) binuclear complexes of the formula [Cu2(H2L)X]2+, where X-= Br-(1), Cl-(2), HO-(3), C2H5O-(4) and C3H3N2- (5). The complexes have been characterized with variable temperature magnetic susceptibility (4.2-300 K) and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral 2J = -6.2 cm-1 for 1, -76.4 cm-1 for 2, -241.9 cm-1 for 3, -231.1 cm-1 for 4 and -343.8 cm-1 for 5. This suggested that there is an antiferromagnetic interaction between the Cu(Ⅱ) ions and the sequence of the effect of some exogenous bridging ligands on magnetic coupling is corresponding to that in spectrochemical series.

Crystal Structure and Magnetic Properties of the Oxamidato-bridged Cu_3 Complex Containing Macrocyclic Ligands

One novel oxamido-bridged trinuclear complex [Cu（CuL）2（ClO4）2] has been syn-thesized and structurally determined.It crystallizes in the monoclinic system,space group P21/n with a = 10.636（4）,b = 11.645（4）,c = 16.038（6） ,β = 91.029（5）°,V = 1986.2（12） 3,C38H32Cl2Cu3N8O12,Mr = 1054.24,Dc = 1.763 Mg/m3,μ（MoKα） = 1.802 mm-1,F（000） = 1066,Z = 2,the final R = 0.0328 and wR = 0.0882 for 3152 observed reflections.The crystal structure is a trinuclear complex in which the CuII ions are bridged by macrocyclic oxamide groups.C-H···O hydrogen bonding interactions link the trinuclear fragment to form a 2D supramolecular architecture.Magnetic measurements indicate that the compound is moderately antiferromagnetically coupled.

Synthesis, Crystal Structure and Properties of a New Binuclear Copper(Ⅱ) Complex with 5-Oxo-4-oxa-tricyclo[4.2.1.0]nonane-9-carboxylic Acid(TNCA)

A new binuclear copper（Ⅱ） complex [Cu2（Hpt）2（TNCA）2（H2O）2]·4 H2O（1） has been synthesized with copper acetate, 5-oxo-4-oxa-tricyclo[4.2.1.0]nonane-9-carboxylic acid（TNCA） and 3-（pyridin-2-yl）-1,2,4-triazole（Hpt）. It crystallizes in the triclinic space group P-1, with a = 8.8199（18）, b = 14.278（3）, c = 15.269（3） A, α = 76.21（3）o, β = 81.07（3）o, γ = 76.07（3）o, V = 1802.7（6） A3, Dc = 1.636 g/cm3, Z = 2, F（000） = 916, the final GOOF = 1.051, R = 0.0556 and wR = 0.1388. The whole molecule consists of two copper ions bridged by two μ2-η^1：η^0-3-（pyridin-2-yl）-1,2,4-triazole anions. The coordination environment of the Cu（1） ion is CuO2N3, giving a distorted square pyramidal geometry. 1 exhibits antiferromagnetic interaction between Cu（Ⅱ） ions, the electron transfer of 1 is irreversible in electrode reactions and the TG analysis shows that 1 is stable below 440 K.

Syntheses,crystal structures and magnetic properties of three lanthanide-nitronyl nitroxide complexes

Three new lanthanide-nitronyl nitroxide radical complexes were successfully synthesized with the formula of [Ln（hfac）3（PyNONIT）2]（Ln=Dy（1）, Tm（2）, Ho（3））. All the complexes were isostructural and crystallized in C2/c space group, in which the central metal ions were eight-coordinated in slightly distorted square antiprism coordination geometries（D4d symmetry）. Magnetic studies indicated the existence of antiferromagnetic interaction in complexes 1–3.

Syntheses of new di-nuclear and tetra-nuclear lanthanide 9-anthracenecarboxylates:Magnetocaloric effect,slow magnetic relaxation and luminescent properties

Lanthanide complex-based materials with magnetic and luminescent properties have received a great deal of attention,owing to their importantly potential applications in diverse fields.In this work,the 9-anthracenecarboxylic acid(9-Haca)as bridging ligand was applied in combination with optically activeπ-conjugated 2,4,6-tri(2-pyridyl)-1,3,5-triazine(tptz)to construct a series of new di-nuclear and tetranuclear lanthanide 9-anthracenecarboxylates[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]·0.25H_(2)O(1),[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]·0.5AQ·CH_(3)COOH_(2)H_(2)O[Ln=Sm(2a),Eu(2b),Gd(2c),Tb(2d),Dy(2e),Tm(2f);AQ=9,10-anthracenedione]and[Ln_(4)(9-aca)_(10)(tptz)_(2)(CH3COO)2]·H_(2)O[Ln=Eu(3a),Gd(3b),Dy(3c)].1 displays a di-nuclear centrosymmetric moiety[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]built up from two complex[La(9-aca)_(2)(tptz)]groups bridged by one H_(2)O molecule and two syn-syn-μ2-η1:η1-9-aca-bridging ligands,while 2a-2f are isostructural and co mprise another di-nuclear centrosymmetric moieties[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]based on two complex[Ln(9-aca)_(2)(tptz)(H_(2)O)]groups connected by two syn-syn-μ2-η1:η1-9-aca-bridging ligands,3a-3c are isostructural and show tetra-nuclear centro symmetric moieties[Ln4(9-aca)10(tptz)2(CH3COO)2]containing three types of coordination modes of 9-aca-ligands.The present compounds offer the only examples of lanthanide 9-anthracenecarboxylates decorated by optically active tptz.Magnetic investigations of 2a,2c-2f,and 3b-3c indicate that 3c is typical of slow relaxation of the magnetization,while 2c and 3b show significant magnetocaloric effect(MCE)with the value of-ΔSm of 5.26 J/(kg·K)at 4 K and 15.65 J/(kg·K)at 2 K(ΔH=7 T),respectively.The luminescent properties were also studied and reveal that the characteristic luminescent properties of the 7r-conjugated aromatic ligands are introduced into magnetic lanthanide 9-anthracenecarboxylates,simultaneously exhibiting slow magnetic relaxation(or MCE)and luminescent properties.