The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bar...The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...展开更多
Amine elimination of Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 with aminophenol H[ON]{H[ON]=2-(CH2 NC5 H10)-4,6-tBu2-C6 H3OH}in 1:2 molar ratio in THF gave the monometallic rare-earth metal amide complexes[ON]2 LnN(SiMe3)2(Ln=Yb(...Amine elimination of Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 with aminophenol H[ON]{H[ON]=2-(CH2 NC5 H10)-4,6-tBu2-C6 H3OH}in 1:2 molar ratio in THF gave the monometallic rare-earth metal amide complexes[ON]2 LnN(SiMe3)2(Ln=Yb(1),Y(2),Gd(3),Sm(4),Nd(5))in 57%-73%isolated yields.All these complexes were characterized by elemental analysis.The molecular structures of complexes 1-4 were determined by single crystal X-ray diffraction.These complexes are highly active for L-Iactide polymerization to give high molecular weight polymers with unimodal molecular weight distributions.In addition,these complexes can also initiate rac-lactide polymerization with high activity to afford heterotactic-rich polylactides.展开更多
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 [Z...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 vip 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.展开更多
The binuclear Schiff base complexes prepared by condensation 2,6-diamino-pyridine and salicylaldehyde (LH) by using microwave and adding metal salts to ligand by same ratio. The Schiff base ligand was checked by infra...The binuclear Schiff base complexes prepared by condensation 2,6-diamino-pyridine and salicylaldehyde (LH) by using microwave and adding metal salts to ligand by same ratio. The Schiff base ligand was checked by infrared, electronic spectra and 1HNMR spectroscopy and prepared complexes characterized by molar conductivity, infrared, electronic spectra and susceptibility measurements. The values of molar conductivities reveal that the complexes are non-electrolytes, from obtained data of electronic spectra and magnetic moment, an octahedral geometry was suggested, coordinated to the metal ions in a manner with N donor sites of imine groups, and oxygen of phenolic OH group.展开更多
Binuclear aluminum alkyl complexes 2a–4g supported by linked bis（β-diketiminate） ligands were synthesized via the reaction of AlEt3 or AlMe3 and the corresponding proligand in a 2：1 molar ratio with moderate yiel...Binuclear aluminum alkyl complexes 2a–4g supported by linked bis（β-diketiminate） ligands were synthesized via the reaction of AlEt3 or AlMe3 and the corresponding proligand in a 2：1 molar ratio with moderate yields. The isolated complexes were well-characterized by ^1H-NMR, ^13C-NMR and elemental analysis. The binuclear nature of aluminum complex 2b was further confirmed by an X-ray diffraction study. All complexes 2a–4g could efficiently initiate the ring-opening polymerization（ROP） of ε-caprolactone in toluene. The substituents at the aromatic rings and the linker unit in the auxiliary ligands exerted significant influence on the catalytic behavior of the investigated aluminum complexes. Complex 4g（R^1 = R^2 = Cl） containing propylenyl bridging unit exhibited the highest catalytic activity among these complexes, which might be attributed to the increased electrophilicity of the metal center as well as more opened coordination sphere. The molecular weights of obtained poly（ε-caprolactone）s deviating considerably from the theoretical values indicated that the ROP of ε-caprolactone by complexes 2a–4g was not well-controlled, which was also judged from the broad molecular weight distributions（MWD = 1.47-2.47） of produced poly（ε-caprolactone）s. These complexes proved to be inactive toward the polymerization of rac-lactide alone. In the presence of alcohol the polymerization occurred, which was actually initiated by the decomposition species of the aluminum complex upon the treatment with isopropanol.展开更多
The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the correspondi...The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the corresponding constrained-geometry complexes L^(1)Ln(CH_(2)SiMe_(3))_(2)(L^(1)=FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(1a),Lu(1b),Sc(1c))and L^(2)Ln(CH_(2)SiMe_(3))_(2)(L^(2)=(2,7-di-tert-butyl)FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(2a),Lu(2b),Sc(2c))in good yields.All these complexes were characterized by NMR spectroscopy,and the solid-state molecular structure of yttrium complex 1a was defined with single-crystal X-ray diffraction analysis.The catalytic performance of these complexes towards 2-vinylpyridine polymerization was investigated,where these complexes alone can efficiently promote the polymerization of 2-vinylpyridine giving isotactic poly(2-vinylpyridine).Upon the activation with[Ph_(3)C][B(C_(6)F_(5))_(4)],the yttrium and lutetium complexes also afford isotactic poly(2-vinylpyridine),while the scandium complexes produce syndiotactic poly(2-vinylpyridine).展开更多
The syndiotactic polymerization of styrene（St） and the copolymerization of St with ethylene（E） were carried out by using a series of chiral half-sandwich rare-earth metal dialkyl complexes（Cp^x＊） as the catalys...The syndiotactic polymerization of styrene（St） and the copolymerization of St with ethylene（E） were carried out by using a series of chiral half-sandwich rare-earth metal dialkyl complexes（Cp^x＊） as the catalysts. The complexes are Ln（CH2SiMe3）2（THF）（1-4： Ln = Sc（1）, Ln = Lu（2）, Ln = Y（3）, Ln = Dy（4）） bearing chiral cyclopentadienyl ligand containing bulky cylcohexane derivatives in the presence of activator and AliBu3. For the St polymerization, a high activity up to 3.1 × 10^6 g of polymer mol Ln^-1·h^-1 and a high syndiotactic selectivity more than 99% were achieved. The resulting syndiotactic polystyrenes（sPSs） have the molecular weights（Mn） ranging from 3700 g·mol^-1 to 6400 g·mol^-1 and the molecular weight distributions（Mw/Mn） from 1.40 to 5.03. As for the copolymerization of St and E, the activity was up to 2.4 × 10^6 g of copolymer mol Sc^-1·h^-1·MPa^-1, giving random St-E copolymers containing syndiotactic polystyrene sequences with different St content in the range of 15 mol%-58 mol%. These results demonstrate that the bulky cyclopentadienyl ligands of the chiral half-sandwich rare-earth metal complexes effectively inhibit the continued insertion of St monomers into the（co）polymer chain to some extent in comparison with the known half-sandwich rare-earth metal complexes.展开更多
The mesomorphie properties of title complexes are investigated by means of DSC and polarizing microscopy. The mesophase temperature ranges of complexes are wider than that of corresponding organic ligands. The bridgin...The mesomorphie properties of title complexes are investigated by means of DSC and polarizing microscopy. The mesophase temperature ranges of complexes are wider than that of corresponding organic ligands. The bridging groups of the complexes have profoand effects on the mesomorphic behavior, When the bridging groups are opticallhy active. the compleve show chiral smectic展开更多
Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In t...Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.展开更多
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 complex...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.展开更多
A binuclear copper（I） complex [Cu2（dppm）2（C7H6N2）2]（NO3）2 （C7H6N2 = benzimidazole, dppm = Ph2PCH2PPh2） has been synthesized and characterized by X-ray crystallography.The crystal belongs to monoclinic, space...A binuclear copper（I） complex [Cu2（dppm）2（C7H6N2）2]（NO3）2 （C7H6N2 = benzimidazole, dppm = Ph2PCH2PPh2） has been synthesized and characterized by X-ray crystallography.The crystal belongs to monoclinic, space group C2/c with a = 14.167（3）, b = 21.209（4）, c =20.680（4）A°, β = 103.93（3）°, C32H28CuN3O3P2, Mr = 628.05, Z = 8, μ = 0.868 mm^-1, V = 6031 （2） ,A°^3,F（000） = 2592, De= 1.383 g/cm^3, R = 0.0593 and wR = 0.1736. A total of 5297 independent reflections were collected, of which 3503 were observed with 1 〉 2σ（/）. The central copper atom is tri-coordinated by phosphorus atoms from bridging dppm and nitrogen atom from benzimidazole. In the coordination sphere, the bond lengths of Cu-P（1） and Cu-P（2） are 2.2607（17） and 2.2503（16） A°,respectively and the P-Cu-P bond angle is 127.26（6）°.展开更多
A direct method of obtaining complexes of cobalt with respect to rare earth elements is reported. The total of 14 new compounds which are insoluble in water and general organic media have been synthesized by the react...A direct method of obtaining complexes of cobalt with respect to rare earth elements is reported. The total of 14 new compounds which are insoluble in water and general organic media have been synthesized by the reaction of RE（Ac）<sub>3</sub>·XH<sub>2</sub>O （RE=rare earth elements except for Ce, Pm; X=2, 5, 8） with [H<sub>6</sub>CO<sub>2</sub>（Gc）<sub>5</sub>CS<sub>2</sub>] （Gc=<sup>-</sup>S<sub>2</sub>CNHCH<sub>2</sub>CO<sub>2</sub><sup>-</sup>） in acetone/ water at room temperature. The complexes having the general formula, [RE<sub>2</sub>Co<sub>2</sub>（Gc）<sub>5</sub>HAcCS<sub>2</sub>·XH<sub>2</sub>O], were characterized by elemental analyses, infrared spectra, DSC and TGA.展开更多
The reaction of NdCl_3 with NaC_5Me_5 generates a novel complex (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 (1). Then (1) reacts with 1 mol ratio Na and a little methyl-naphthalene generating another novel complex (C_5Me_5)_2Nd(...The reaction of NdCl_3 with NaC_5Me_5 generates a novel complex (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 (1). Then (1) reacts with 1 mol ratio Na and a little methyl-naphthalene generating another novel complex (C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2 (2).Complex (1) belongs to orthorhombic crystal system,space group Pbn2_1 with a=1.2635(3) nm,b=1.6127(5) nm,c=1.6543(4J nm,V=3.371(2) nm^3,D_c=1.36 gcm^(-3) and Z=4.The central metal Nd is coordinated by two C_5Me5 ring centroids and two μ-chlorine atoms forming a distorted tetrahedron.The crystal of complex (2) is monoclinic,space group C2/n with a=1.7482(5) nm, b=1.3260(4) nm,c=1.6406(7) nm,β=109.39(3)°,V=3.5874(1) nm^3,D_c=1.26 gcm^(-3) and Z=4,Two five-membered ring centroids and two p-oxygens of OCH_3 form a distorted tetrahedron around the central neodymium ion.展开更多
In this work, we report a theoretical exploration of the ground-state electronic structures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theo...In this work, we report a theoretical exploration of the ground-state electronic structures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory （DFT） employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [（η^5-C5Me5）2Zr]2（μ^2, η^2, η^2-N2） is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO＋ 1 molecular orbital as compared with the reactant 1 [（η^5-C5Me4H）2Zr]2（μ2,η^2,η^2-N2）. Besides, the structural feature of the hypothetical intermediate 1′, [（η^5C5Me4H）2Zr]2（μ2,η^2, η^2-N2）-n2, clearly implies the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [（η^5-C5Me4H）2ZrH]2（μ2,η^2,η^2-N2H2）, indicates that the asymmetric stretching of Zr-N and Zr-H leads to dissociation. Moreover, the vibrational intensity of Zr-H is stronger than that of Zr-N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr-N bonds.展开更多
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 work...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-展开更多
Two binuclear silver complexes, [Ag2{μ-S2P（OCH2Ph）2}2（phen）2] （1） and [Ag2{μ- SEP（OCH2CH2Ph）2}E（phen）2] （2）, were synthesized and characterized by elemental analysis, infrared spectrum, thermo-gravimetri...Two binuclear silver complexes, [Ag2{μ-S2P（OCH2Ph）2}2（phen）2] （1） and [Ag2{μ- SEP（OCH2CH2Ph）2}E（phen）2] （2）, were synthesized and characterized by elemental analysis, infrared spectrum, thermo-gravimetric analysis and X-ray single-crystal diffraction. Complex 1 crystallizes in the triclinic system, space group P1 with a = 9.7881（4）, b = 10.7726（4）, c = 13.1952（6） A, a = 103.686（4）, ,8= 99.477（3）, ）, = 107.494（4）°, F= 1246.88（9）A3, Dc = 1.591 g.m-3 and Z = 1; Complex 2 is of monoclinic system, space group P2jn with a = 10.6014（8）, b = 24.3969（15）, c = 11.5353（10）A,β= 14.125（10）°, F= 2722.9（4） A3, Dc = 1.526 g.m-3 and Z = 2. In the molecules of 1 and 2, O,O＇-dialkyldithiophosphate anions, （PhCHEO）PS2 and （PhCH2CHEO）PS2 act as bridging ligands and connect two Ag（I） centers into a binuclear unit with AgES4P2 eight-membered rings in ＂chair＂ conformations. In both crystal structures, face-to-face π-π stacking interactions between the adjacent paralleling aromatic rings of 1,10-phenanthroline play a prominent role in the crystal packing and result in a 1D chain. And such 1D chains are further linked into 3D networks by weak intermolecular C-H...π interactions for 1.展开更多
The electronic structure and electronic absorption spectra of binuclear Au(Ⅰ) complexes with bidentate phophines and a bidentate ylid ligand have been studied using quasirelativistic pseudopotential ab initio cal...The electronic structure and electronic absorption spectra of binuclear Au(Ⅰ) complexes with bidentate phophines and a bidentate ylid ligand have been studied using quasirelativistic pseudopotential ab initio calculations at the HF and MP2 levels by the LANL2DZ basis sets. The electronic properties of the spectral transition and Au(Ⅰ)—Au(Ⅰ) interaction were also discussed.展开更多
Four new binuclear Fe(Ⅲ) complexes containing the diboon of isophthallc acid as bridge have been synthesized, namely [Fe2(IPHTA)(L)4](ClO4)4[L denotes 2, 2'-bipyridyl (bpy); 1,10-phenanthroline (phen); 4, 4'-...Four new binuclear Fe(Ⅲ) complexes containing the diboon of isophthallc acid as bridge have been synthesized, namely [Fe2(IPHTA)(L)4](ClO4)4[L denotes 2, 2'-bipyridyl (bpy); 1,10-phenanthroline (phen); 4, 4'-dimethyl-2, 2'-bipyridyl (Me2bpy ) and 5-nitro-1, 10-phenanthroline (NO2-phen), respectively], where IPHTA represents the isophthalate dianion. The complex [Fe2(IPHTA)(phen)4](CIO4)4 was characterized with variable temperature magnetic susceptibility (4-300K). The exchange integral J was found to be 9. 96cm(-1), indicating that weakly ferromagnetic spin-exchange interaction operates between Fe(Ⅲ) and Fe(Ⅲ) ions.展开更多
Two new binuclear complexes, [M2(μ-NITpBA)4(H2O)2] (M = Zn 1 and Cu 2) [where NIpBA =?2-(4-carboxyl-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide], were stylized and characterized. Magnetic susce...Two new binuclear complexes, [M2(μ-NITpBA)4(H2O)2] (M = Zn 1 and Cu 2) [where NIpBA =?2-(4-carboxyl-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide], were stylized and characterized. Magnetic susceptibility measurements revealed antiferromagnetic exchange interactions in two complexes.展开更多
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
基金the Project of Natural Science Foundation of Gansu Province of their financial supports(No. 096RJZA117)
文摘The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...
基金Project supported by the National Natural Science Foundation of China(21572205,21971130,21871198,21674070)the Natural Science Foundation of Zhejiang Province(LY19B040002)+2 种基金the State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciencesthe Natural Science Foundation of Ningbo Municipal(2019A610030,2019A610129)K.C.Wong Magna Fund in Ningbo University。
文摘Amine elimination of Ln[N(SiMe3)2]3(μ-Cl)Li(THF)3 with aminophenol H[ON]{H[ON]=2-(CH2 NC5 H10)-4,6-tBu2-C6 H3OH}in 1:2 molar ratio in THF gave the monometallic rare-earth metal amide complexes[ON]2 LnN(SiMe3)2(Ln=Yb(1),Y(2),Gd(3),Sm(4),Nd(5))in 57%-73%isolated yields.All these complexes were characterized by elemental analysis.The molecular structures of complexes 1-4 were determined by single crystal X-ray diffraction.These complexes are highly active for L-Iactide polymerization to give high molecular weight polymers with unimodal molecular weight distributions.In addition,these complexes can also initiate rac-lactide polymerization with high activity to afford heterotactic-rich polylactides.
基金supported by the Project for Undergraduate Research Study and Innovative Experiment of Hunan Provincial(2013-191)National Undergraduate Training Programs for Innovation and Entrepreneurship(201310551158)+4 种基金the Scientific Research Fund of Hunan Provincial Education Department(13B029,13A030)the Key Laboratory of Functional Organometallic Materials of Hunan Province College(13K09,13K10)the Program for Excellent Talents in Hunan University of Science and Engineeringthe Construct Program of the Key Discipline in Hunan Province(2011-76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2012-318)
文摘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 vip 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.
文摘The binuclear Schiff base complexes prepared by condensation 2,6-diamino-pyridine and salicylaldehyde (LH) by using microwave and adding metal salts to ligand by same ratio. The Schiff base ligand was checked by infrared, electronic spectra and 1HNMR spectroscopy and prepared complexes characterized by molar conductivity, infrared, electronic spectra and susceptibility measurements. The values of molar conductivities reveal that the complexes are non-electrolytes, from obtained data of electronic spectra and magnetic moment, an octahedral geometry was suggested, coordinated to the metal ions in a manner with N donor sites of imine groups, and oxygen of phenolic OH group.
基金financially supported by the National Natural Science Foundation of China (Nos. 20604009 and 21474028)
文摘Binuclear aluminum alkyl complexes 2a–4g supported by linked bis（β-diketiminate） ligands were synthesized via the reaction of AlEt3 or AlMe3 and the corresponding proligand in a 2：1 molar ratio with moderate yields. The isolated complexes were well-characterized by ^1H-NMR, ^13C-NMR and elemental analysis. The binuclear nature of aluminum complex 2b was further confirmed by an X-ray diffraction study. All complexes 2a–4g could efficiently initiate the ring-opening polymerization（ROP） of ε-caprolactone in toluene. The substituents at the aromatic rings and the linker unit in the auxiliary ligands exerted significant influence on the catalytic behavior of the investigated aluminum complexes. Complex 4g（R^1 = R^2 = Cl） containing propylenyl bridging unit exhibited the highest catalytic activity among these complexes, which might be attributed to the increased electrophilicity of the metal center as well as more opened coordination sphere. The molecular weights of obtained poly（ε-caprolactone）s deviating considerably from the theoretical values indicated that the ROP of ε-caprolactone by complexes 2a–4g was not well-controlled, which was also judged from the broad molecular weight distributions（MWD = 1.47-2.47） of produced poly（ε-caprolactone）s. These complexes proved to be inactive toward the polymerization of rac-lactide alone. In the presence of alcohol the polymerization occurred, which was actually initiated by the decomposition species of the aluminum complex upon the treatment with isopropanol.
基金Project supported by National Natural Science Foundation of China(21805143)Natural Science Foundation of Zhejiang Province(LY21B040002)+1 种基金Natural Science Foundation of Ningbo(202003N4110)the K.C.Wong Magna Fund from Ningbo University。
文摘The metathesis reaction between pyrrolidinyl-ethylene fluorenyl lithium salts with in situ prepared cationic rare-earth metal dialkyl species[Ln(CH_(2)SiMe_(3))_(2)(THF)_(x)][BPh_(4)]afford efficiently the corresponding constrained-geometry complexes L^(1)Ln(CH_(2)SiMe_(3))_(2)(L^(1)=FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(1a),Lu(1b),Sc(1c))and L^(2)Ln(CH_(2)SiMe_(3))_(2)(L^(2)=(2,7-di-tert-butyl)FluCH_(2)CH_(2)NC_(4)H_(8),Ln=Y(2a),Lu(2b),Sc(2c))in good yields.All these complexes were characterized by NMR spectroscopy,and the solid-state molecular structure of yttrium complex 1a was defined with single-crystal X-ray diffraction analysis.The catalytic performance of these complexes towards 2-vinylpyridine polymerization was investigated,where these complexes alone can efficiently promote the polymerization of 2-vinylpyridine giving isotactic poly(2-vinylpyridine).Upon the activation with[Ph_(3)C][B(C_(6)F_(5))_(4)],the yttrium and lutetium complexes also afford isotactic poly(2-vinylpyridine),while the scandium complexes produce syndiotactic poly(2-vinylpyridine).
基金financially supported by the National Natural Science Foundation of China (Nos. 20974014, 21274012, 21322401 and 21774014)the 111 project (No. B07012)
文摘The syndiotactic polymerization of styrene（St） and the copolymerization of St with ethylene（E） were carried out by using a series of chiral half-sandwich rare-earth metal dialkyl complexes（Cp^x＊） as the catalysts. The complexes are Ln（CH2SiMe3）2（THF）（1-4： Ln = Sc（1）, Ln = Lu（2）, Ln = Y（3）, Ln = Dy（4）） bearing chiral cyclopentadienyl ligand containing bulky cylcohexane derivatives in the presence of activator and AliBu3. For the St polymerization, a high activity up to 3.1 × 10^6 g of polymer mol Ln^-1·h^-1 and a high syndiotactic selectivity more than 99% were achieved. The resulting syndiotactic polystyrenes（sPSs） have the molecular weights（Mn） ranging from 3700 g·mol^-1 to 6400 g·mol^-1 and the molecular weight distributions（Mw/Mn） from 1.40 to 5.03. As for the copolymerization of St and E, the activity was up to 2.4 × 10^6 g of copolymer mol Sc^-1·h^-1·MPa^-1, giving random St-E copolymers containing syndiotactic polystyrene sequences with different St content in the range of 15 mol%-58 mol%. These results demonstrate that the bulky cyclopentadienyl ligands of the chiral half-sandwich rare-earth metal complexes effectively inhibit the continued insertion of St monomers into the（co）polymer chain to some extent in comparison with the known half-sandwich rare-earth metal complexes.
文摘The mesomorphie properties of title complexes are investigated by means of DSC and polarizing microscopy. The mesophase temperature ranges of complexes are wider than that of corresponding organic ligands. The bridging groups of the complexes have profoand effects on the mesomorphic behavior, When the bridging groups are opticallhy active. the compleve show chiral smectic
基金financially supported by the National Natural Science Foundation of China(No.21172269)the Fundamental Research Funds for the Central Universities,SouthCentral Minzu University(No.CZH24005)。
文摘Binuclear complexes have attracted extensive attention in fields such as catalysis because of their likely bimetallic synergistic effect;however,the mechanism and factors influencing this synergism remain unclear.In this work,six bis-β-ketoimine binuclear titanium complexes4a-4f containing different alkylthio sidearms and configurations were synthesized and characterized by nuclear magnetic resonance hydrogen spectrum(~1H-NMR),nuclear magnetic resonance carbon spectrum(^(13)C-NMR),Fourier transform infrared spectrum(FTIR),and elemental analysis.The intermetallic distances of isomeric complexes 4a,4d,4e and 4f determined through density functional theory(DFT)optimization were in the order 4a<4d<4e<4f and were found to significantly influence the catalytic performance for ethylene(co)polymerization.These complexes could efficiently catalyze ethylene polymerization and ethylene/1-hexene or ethylene/1-octene copolymerization with high activity to produce highmolecular-weight ethylene homo-and co-polymers.Among the three binuclear titanium complexes 4a-4c with similar structures but different lengths of alkylthio sidearms,complex 4a,which contained the shortest methylthio sidearm,exhibited the highest activity for ethylene polymerization and copolymerization with 1-hexene or 1-octene.Additionally,for ethylene/1-hexene or ethylene/1-octene copolymerization,it showed the highest comonomer incorporation compared with propylthio(4b)and octylthio(4c)derivatives because of the smaller steric hindrance of the methyl group in 4a and the more open coordination space for vinyl monomers.Furthermore,among the isomeric complexes 4a,4d,4e and4f,complex 4a with the shortest bimetallic distance also exhibited the highest activity towards ethylene(co)polymerization,and the highest 1-hexene or 1-octene incorporation in comparison with its regioisomeric counterparts 4d,4e and p-phenyl-bridged analog 4f,owing to a more appropriate bimetallic distance that is conducive to a synergistic effect.
基金Supported by the National Natural Science Foundation of China
文摘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.
基金This work was supported by the National Natural Science Foundation of China (No. 20271017) and Henan Provincial Innovation Foundation (No. 0421001300)
文摘A binuclear copper（I） complex [Cu2（dppm）2（C7H6N2）2]（NO3）2 （C7H6N2 = benzimidazole, dppm = Ph2PCH2PPh2） has been synthesized and characterized by X-ray crystallography.The crystal belongs to monoclinic, space group C2/c with a = 14.167（3）, b = 21.209（4）, c =20.680（4）A°, β = 103.93（3）°, C32H28CuN3O3P2, Mr = 628.05, Z = 8, μ = 0.868 mm^-1, V = 6031 （2） ,A°^3,F（000） = 2592, De= 1.383 g/cm^3, R = 0.0593 and wR = 0.1736. A total of 5297 independent reflections were collected, of which 3503 were observed with 1 〉 2σ（/）. The central copper atom is tri-coordinated by phosphorus atoms from bridging dppm and nitrogen atom from benzimidazole. In the coordination sphere, the bond lengths of Cu-P（1） and Cu-P（2） are 2.2607（17） and 2.2503（16） A°,respectively and the P-Cu-P bond angle is 127.26（6）°.
文摘A direct method of obtaining complexes of cobalt with respect to rare earth elements is reported. The total of 14 new compounds which are insoluble in water and general organic media have been synthesized by the reaction of RE（Ac）<sub>3</sub>·XH<sub>2</sub>O （RE=rare earth elements except for Ce, Pm; X=2, 5, 8） with [H<sub>6</sub>CO<sub>2</sub>（Gc）<sub>5</sub>CS<sub>2</sub>] （Gc=<sup>-</sup>S<sub>2</sub>CNHCH<sub>2</sub>CO<sub>2</sub><sup>-</sup>） in acetone/ water at room temperature. The complexes having the general formula, [RE<sub>2</sub>Co<sub>2</sub>（Gc）<sub>5</sub>HAcCS<sub>2</sub>·XH<sub>2</sub>O], were characterized by elemental analyses, infrared spectra, DSC and TGA.
基金The project supported by the National Natural Science Foundation of China
文摘The reaction of NdCl_3 with NaC_5Me_5 generates a novel complex (C_5Me_5)_2Nd(μ-Cl)_2Na(DME)_2 (1). Then (1) reacts with 1 mol ratio Na and a little methyl-naphthalene generating another novel complex (C_5Me_5)_2Nd(μ-OCH_3)_2Na(DME)_2 (2).Complex (1) belongs to orthorhombic crystal system,space group Pbn2_1 with a=1.2635(3) nm,b=1.6127(5) nm,c=1.6543(4J nm,V=3.371(2) nm^3,D_c=1.36 gcm^(-3) and Z=4.The central metal Nd is coordinated by two C_5Me5 ring centroids and two μ-chlorine atoms forming a distorted tetrahedron.The crystal of complex (2) is monoclinic,space group C2/n with a=1.7482(5) nm, b=1.3260(4) nm,c=1.6406(7) nm,β=109.39(3)°,V=3.5874(1) nm^3,D_c=1.26 gcm^(-3) and Z=4,Two five-membered ring centroids and two p-oxygens of OCH_3 form a distorted tetrahedron around the central neodymium ion.
基金Supported by the National Natural Science Foundation of China (No. 20573114)MOST Project of 2006DFA43020 and 2007CB815307
文摘In this work, we report a theoretical exploration of the ground-state electronic structures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory （DFT） employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [（η^5-C5Me5）2Zr]2（μ^2, η^2, η^2-N2） is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO＋ 1 molecular orbital as compared with the reactant 1 [（η^5-C5Me4H）2Zr]2（μ2,η^2,η^2-N2）. Besides, the structural feature of the hypothetical intermediate 1′, [（η^5C5Me4H）2Zr]2（μ2,η^2, η^2-N2）-n2, clearly implies the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [（η^5-C5Me4H）2ZrH]2（μ2,η^2,η^2-N2H2）, indicates that the asymmetric stretching of Zr-N and Zr-H leads to dissociation. Moreover, the vibrational intensity of Zr-H is stronger than that of Zr-N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr-N bonds.
基金Supported by the National Natural Science Foundation of China
文摘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-
基金supported by the project of Science&Technology Department of Sichuan Province(2011JY0052,2012JY0115)Sichuan University of Science&Engineering(2012PY04,2012PY14,2012KY12)University Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education(LZJ1203,LYJ1301,LYJ1306)
文摘Two binuclear silver complexes, [Ag2{μ-S2P（OCH2Ph）2}2（phen）2] （1） and [Ag2{μ- SEP（OCH2CH2Ph）2}E（phen）2] （2）, were synthesized and characterized by elemental analysis, infrared spectrum, thermo-gravimetric analysis and X-ray single-crystal diffraction. Complex 1 crystallizes in the triclinic system, space group P1 with a = 9.7881（4）, b = 10.7726（4）, c = 13.1952（6） A, a = 103.686（4）, ,8= 99.477（3）, ）, = 107.494（4）°, F= 1246.88（9）A3, Dc = 1.591 g.m-3 and Z = 1; Complex 2 is of monoclinic system, space group P2jn with a = 10.6014（8）, b = 24.3969（15）, c = 11.5353（10）A,β= 14.125（10）°, F= 2722.9（4） A3, Dc = 1.526 g.m-3 and Z = 2. In the molecules of 1 and 2, O,O＇-dialkyldithiophosphate anions, （PhCHEO）PS2 and （PhCH2CHEO）PS2 act as bridging ligands and connect two Ag（I） centers into a binuclear unit with AgES4P2 eight-membered rings in ＂chair＂ conformations. In both crystal structures, face-to-face π-π stacking interactions between the adjacent paralleling aromatic rings of 1,10-phenanthroline play a prominent role in the crystal packing and result in a 1D chain. And such 1D chains are further linked into 3D networks by weak intermolecular C-H...π interactions for 1.
文摘The electronic structure and electronic absorption spectra of binuclear Au(Ⅰ) complexes with bidentate phophines and a bidentate ylid ligand have been studied using quasirelativistic pseudopotential ab initio calculations at the HF and MP2 levels by the LANL2DZ basis sets. The electronic properties of the spectral transition and Au(Ⅰ)—Au(Ⅰ) interaction were also discussed.
文摘Four new binuclear Fe(Ⅲ) complexes containing the diboon of isophthallc acid as bridge have been synthesized, namely [Fe2(IPHTA)(L)4](ClO4)4[L denotes 2, 2'-bipyridyl (bpy); 1,10-phenanthroline (phen); 4, 4'-dimethyl-2, 2'-bipyridyl (Me2bpy ) and 5-nitro-1, 10-phenanthroline (NO2-phen), respectively], where IPHTA represents the isophthalate dianion. The complex [Fe2(IPHTA)(phen)4](CIO4)4 was characterized with variable temperature magnetic susceptibility (4-300K). The exchange integral J was found to be 9. 96cm(-1), indicating that weakly ferromagnetic spin-exchange interaction operates between Fe(Ⅲ) and Fe(Ⅲ) ions.
文摘Two new binuclear complexes, [M2(μ-NITpBA)4(H2O)2] (M = Zn 1 and Cu 2) [where NIpBA =?2-(4-carboxyl-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide], were stylized and characterized. Magnetic susceptibility measurements revealed antiferromagnetic exchange interactions in two complexes.
文摘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
