The liquid-phase direct catalytic amination of benzene to aniline was performed in acetic acid water solvent using a series of vanadium （Ⅲ, Ⅳ,Ⅴ） complexes with N,O- or O,O-ligands as catalysts and hydroxylamine h...The liquid-phase direct catalytic amination of benzene to aniline was performed in acetic acid water solvent using a series of vanadium （Ⅲ, Ⅳ,Ⅴ） complexes with N,O- or O,O-ligands as catalysts and hydroxylamine hydrochloride as the aminating agent. The vanadium complexes exhibited much higher selectivity towards the production of aniline than NaVO3 or VOSO4. Under the optimized conditions, an aniline yield of 42.5% and a TON of 48 with a high selectivity of above 99.9% was obtained using 0.2 mmol of [VO（OAc）2] as the catalyst.展开更多
Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other ...Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V,V)complex with an oxo bridge.The conversion between the two complexes had been discussed.展开更多
Crystal structure of pyridine-2,6-dicarboxylate(dipc) vanadium complex:[(dipc)VO_2]_2( 4, 4'-bipyridine)·4H_2O(M_r=724.34) is monoclinic with space group C2/c and a=25.857(8),b=6.896(1),c=16.267(5),β=106.27(...Crystal structure of pyridine-2,6-dicarboxylate(dipc) vanadium complex:[(dipc)VO_2]_2( 4, 4'-bipyridine)·4H_2O(M_r=724.34) is monoclinic with space group C2/c and a=25.857(8),b=6.896(1),c=16.267(5),β=106.27(4)°,V=2784.62 D_c=1.73 g/cm￣3,F(000)=1472,Z=4.The structural solutions and refinements based on 1661 reflections (I>2σ(I))converged at R=0. 043.The coordinated number of vanadium atom is 5,the geometrical form of the five atoms are coordinated to the vanadium atom is a distorted tetragonal bipyramid of which the four coordinated atoms O(3),O(5),N(1) and O(2) make up the equatorial plane,while the other coordinated atom O(1) is to occupy the apex.展开更多
A novel imidazole-functionalized dioxovanadium complex [V2O2（C2O4）（aIM）4] （aIM =1-allylimidazole） was synthesized by the reaction of VO（acac）2 with 1-allylimidazole and fully characterized by single-crystal X-...A novel imidazole-functionalized dioxovanadium complex [V2O2（C2O4）（aIM）4] （aIM =1-allylimidazole） was synthesized by the reaction of VO（acac）2 with 1-allylimidazole and fully characterized by single-crystal X-ray diffraction （SCXRD）,powder X-ray diffraction （PXRD）,X-ray photoelectron spectroscopy （XPS）,Fourier transform infrared spectroscopy （FT-IR） and elemental analyses.Interestingly,the oxalate was in-situ generated from the acetylacetone anion of VO（acac）2 and further coordinated with the vanadium cation and finally complex 1 was achieved.The crystal of complex 1 belongs to the monoclinic system,space group P21/n with a =10.7922（9）,b =10.6296（8）,c =13.2936（11） （A）,μ =0.677 mm^-1,Mr =686.48,V =1516.9（2） A^3,Z =2,Dc =1.503 g/cm^3,F（000） =708,R =0.0543,and wR =0.1517 for 2459 observed reflections with Ⅰ 〉 2σ（Ⅰ）.Notably,complex 1 is further used as catalyst in the oxidation of sulfides using H2O2 as the oxidant and exhibits excellent catalytic performance （conv.up to 95.6%,sele.up to 98.9%）.展开更多
The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with V...The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination method.This methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination method.The catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky effect.The vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ligand.Moreover,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.展开更多
The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n wi...The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n with α = 10.3153（15）, b = 7.4024（11 ）, c = 24.413（4） A, β = 101.911（2）°, V= 1824.0（5） A^3, Z= 4, Mr = 427.28, Dc = 1.556 g/cm^3, F（000） = 880,μ（MoKα） = 0.591, the final R = 0.0372 and wR = 0.0926. The vanadium（V） atom adopts a distorted square-pyramidal geometry coordinated by the tridentate ligand and two oxygen atoms. The hydrogen bonds and strong π-π stacking interactions link the complex molecules into a 3-D network structure.展开更多
A resistive-type relative humidity （RH） sensor based on vanadium complex （VO2（3-f[）） film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film o...A resistive-type relative humidity （RH） sensor based on vanadium complex （VO2（3-f[）） film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film of vanadium complex was coated as a humidity-sensing material on the top of the pre-patterned electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated sensing element upon adsorption/desorption of water vapor. The resistance of the humidity sensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 35%-70% RH. The overall resistance of the sensor decreases 11 times. An equivalent circuit for the VO2（3-fl） based resistive-type humidity sensor was developed. The properties of the sensor studied in this work make it beneficial for use in the instruments for environmental monitoring of humidity.展开更多
Two hydrazone ligands （E）-N＇-（2-hydroxy-5-methoxybenzylidene）-2-hydroxybenzo- hydrazide （HLa） and （E）-N＇-（3,5-dichloro-2- hydroxybenzylidene）-4-methoxybenzohydrazide （HLb） were prepared and characterized...Two hydrazone ligands （E）-N＇-（2-hydroxy-5-methoxybenzylidene）-2-hydroxybenzo- hydrazide （HLa） and （E）-N＇-（3,5-dichloro-2- hydroxybenzylidene）-4-methoxybenzohydrazide （HLb） were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone ligands, two new structurally similar vanadium（V） complexes, [VOLaL].CH3OH （1） and [vOLbL] （2）, where L is the monoanionic form of benzohydroxamic acid （HL）, were prepared and characterized by IR and UV-Vis spectra, and single-crystal X-ray diffraction. Complex 1 crystallizes as the monoclinic space group P21/n, with a = 7.5208（10）, b = 15.490（2）, c = 20.8929（18） A, β = 96.373（2）°, V = 2418.9（5） A3, Z = 4, R = 0.0831, wR = 0.2607 and GOOF = 1.061. Complex 2 crystallizes as the monoclinic space group P21/c, with a = 11.8577（18）, b = 16.468（2）, c = 12.2288（18） A, β = 106.064（2）°, V= 2294.7（6） A3, Z = 4, R= 0.0741, wR= 0.1745 and GOOF= 1.014. X-ray analysis indicates that the complexes are mononuclear vanadium （V） species, with the V atoms located in the octahedral coordination. The hydrazone ligands and the complexes were evaluated for their antibacterial （Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence） and antifungal （Candida albicans and Aspergillus niger） activities by MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide） method.展开更多
A vanadium complex （VO2（3-fl）） and CNT composite film based temperature sensor is reported in this study. Surface-type silver electrodes were deposited on the glass substrates. A thin film of VOE（3-fl） and CNT c...A vanadium complex （VO2（3-fl）） and CNT composite film based temperature sensor is reported in this study. Surface-type silver electrodes were deposited on the glass substrates. A thin film of VOE（3-fl） and CNT composite was coated as a temperature-sensing material on the top of the pre-patterned Ag electrodes. The temperature-sensing principle of the sensor was based on the conductivity change of the coated sensing element upon heating or cooling processes. DC and AC （100 Hz） resistances of the temperature sensor decreased quasi- linearly with increasing the temperature in the range of 25-80 ℃. The overall resistance of the sensor decreases by 1.8-2.1 and 1.9-2.0 times at DC and AC voltage, respectively. The resistance temperature coefficients of the sensor were in the range of-（0.9-1.3）% and -（1.1-1.3）% at DC and AC voltage, respectively. The properties of the sensor studied in this work, make it beneficial to be used in the instruments for environmental monitoring of temperature.展开更多
The new oxovanadium (V) complex, [PyH][VO2(L)] 1 (salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L; Hpy is protonated pyridine) was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-me...The new oxovanadium (V) complex, [PyH][VO2(L)] 1 (salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L; Hpy is protonated pyridine) was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-pyridine. Similarly, another new complex, [VO(L)(OCH3)] 2 was synthesized by refluxing VOSO4 and H2L in methanol-pyridine. Crystal data for 1: C19H15N3O5BrV, Mr= 496.2, monoclinic, P21/n, a = 7.1885(3), b = 9.2718(3), c = 28.803(1) A, β = 96.185(1)°, Z = 4 and V = 1908.6(1) A3; for 2: C15H12N2O5BrV, Mr= 431.1, monoclinic, P2,/n, a = 12.202(2), b = 8.045(2), c = 16.604(3) A, β = 101.29(3)°, Z = 4 and V = 1598.4(2) A3. The structures of 1 and 2 have been determined by X-ray analyses and reveal that the coordination environments of V atoms in both complexes are of square-based pyramid. Three of the four based donor atoms are from the tridentate 'ONO' donor ligand while the fourth is one terminal oxygen atom with the V(1) - O(3) distance 1.646(4) A for 1 and one -OCH3 group with the V(1)-O(3) distance 1.753(3) A for 2. The V(1)-O(4) terminals occupy the axial sites in both cases. The complexes are also characterized by IR and 1H NMR spectroscopies.展开更多
Divanadium（Ⅴ） complex [VO（aptch）（μ-OCH3）]2（1） and two monovanadium（Ⅴ） complexes [VO（apfah））（OEt）]（2a and 2b,H2aptch = 2-hydroxyacetophenone thiophene-2-car-boxylic hydrazone,H2apfah = 2-hydroxyaceto...Divanadium（Ⅴ） complex [VO（aptch）（μ-OCH3）]2（1） and two monovanadium（Ⅴ） complexes [VO（apfah））（OEt）]（2a and 2b,H2aptch = 2-hydroxyacetophenone thiophene-2-car-boxylic hydrazone,H2apfah = 2-hydroxyacetophenone 2-furoic acid hydrazone） have been synthesized and characterized.Single-crystal X-ray diffraction studies reveal that 1 is a cen-trosymmetric dimer bridged by two methoxido O-atoms.Complex 1 crystallizes in the monoclinic crystal system,space groups P21/c with a = 7.4825（4）,b = 17.0928（11）,c = 11.6961（7） ,β = 98.172（4）o,Z = 2,F（000） = 728,μ = 0.829 mm-1,the final R = 0.0457 and wR = 0.1137 for 2654 observed reflections with I 〉 2（I）.The vanadium（V） is coordinated to the tridentate ligand,ethanol molecule to form a distorted square-pyramidal geometry,complexes 2a and 2b.Although 2a and 2b have the same asymmetric unit,they belong to different space groups.Complex 2a crystallizes in the monoclinic crystal system,space groups P21/n with a = 10.2293（2）,b = 15.6660（3）,c = 10.6298（2） ,β = 116.259（1）o,Z = 4,μ = 0.676 mm-1;complex 2b crystallizes in the triclinic crystal system,space groups P with a = 8.2808（4）,b = 9.4704（5）,c = 10.0819（5） ,α = 86.133（3）,= 81.956（3）,γ = 80.248（3）o,Z = 2 and μ = 0.670 mm-1.The hydrogen bonds are found to exist in 2b only.The crystal structure is stabilized by intermolecular hydrogen bonds of C-H···O.展开更多
A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure dete...A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure determination. The complex crystallizes in the monoclinic system, space group P21/c with a = 11.232（2）, b = 10.762（2）, c = 112.613（3）, β = 99.44（3）°, V = 1504.1（5）3, Dc = 1.657 g·cm-3, Z = 4, F（000） = 768, μ = 0.827 mm-1, the final R = 0.0392 and wR = 0.1073 for 2266 observed reflections with I 〉 2σ（I）. Single-crystal X-ray diffraction studies reveal that the vanadium（V） is coordinated by a tridentate ligand, methanol molecule and peroxo group to form a pentagonal-bipyramidal geometry. The crystal structure is stabilized by intermolecular hydrogen bonds of O-H···N and C-H···O.展开更多
A new heteronuclear complex, dimer [(2-OH2)2Ba2(H2O)4][VO2(tpa)]24H2O (tpa: 2,4,6-tripicolinate trianion), was synthesized and structurally determined by X-ray diffraction technique where all hydrogen atoms have been ...A new heteronuclear complex, dimer [(2-OH2)2Ba2(H2O)4][VO2(tpa)]24H2O (tpa: 2,4,6-tripicolinate trianion), was synthesized and structurally determined by X-ray diffraction technique where all hydrogen atoms have been located directly. The coordination geometry of V(V) ion is a distorted trigonal bipyrimid and that of Ba(II) ion is a capped square antiprism. One 2-O bridging bond and two hydrogen bonds act between the coordination geometries. A 1-D extended porous construction containing 20-member cavities is observed in the crystal.展开更多
Two novel VO(IV) Schiff base complexes, VO(SALHA)2[SALHA: salicyaldehyde- oxyammonia] and VO(o-VANHA)2 [o-VANHA: o-vanillin-oxyammonia], have been synthesized with salicyaldehyde or o-vanilline, hydroxylammonium chlor...Two novel VO(IV) Schiff base complexes, VO(SALHA)2[SALHA: salicyaldehyde- oxyammonia] and VO(o-VANHA)2 [o-VANHA: o-vanillin-oxyammonia], have been synthesized with salicyaldehyde or o-vanilline, hydroxylammonium chloride and vanadyl sulfate in absolute methanol, and their crystal structures were determined by single-crystal X-ray diffraction. The vanadium(IV) centers in both complexes are five-coordinate in a distorted square pyramidal geometry. VO(SALHA)2 (C14H12N2O5V, Mr = 339.20) crystallizes in the monoclinic system, space group P21/n with a = 14.716(9), b = 7.175(5), c = 14.716(9) ? b = 113.130(7), V = 1428.8(15) 3, Z = 4, Dc = 1.577 g/cm3, l = 0.71073 ? m(MoKa) = 0.720 mm-1, F(000) = 692, the final R = 0.0466 and wR = 0.0829 for 1561 observed reflections (I > 2s(I)). VO(o-VANHA)2 (C16H16N2O7V, Mr = 399.25) is of monoclinic, space group P21/n with a = 11.386(12), b = 10.405(10), c = 14.627(15) , b = 93.654(19), V = 1729(3) 3, Z = 4, Dc = 1.533 g/cm3, l = 0.71073 , m(MoKa) = 0.615 mm-1, F(000) = 820, the final R = 0.0513 and wR = 0.1129 for 1235 observed reflections (I > 2s(I)).展开更多
Two oxo-vanadium（IV） complexes, [VO（C2O4）（2,2′-bipy）（H2O）]·C2H5OH（1） and VO（C2O4）（phen）（H2O） （2）, where 2,2′-bipy=2,2′-bipyridyl, phen=1,10-phenanthroline, were synthesized as potential funct...Two oxo-vanadium（IV） complexes, [VO（C2O4）（2,2′-bipy）（H2O）]·C2H5OH（1） and VO（C2O4）（phen）（H2O） （2）, where 2,2′-bipy=2,2′-bipyridyl, phen=1,10-phenanthroline, were synthesized as potential functional models of vanadium haloperoxidases（VHPOs） in mixed solvent of ethanol and water at room temperature. The complexes were characterized by elemental analysis, infrared（IR）, UV-Vis and X-ray crystallography. Structural analyses showed that vanadium atom was coordinated by a terminal oxygen, one oxygen atom from coordinated water, two oxygen atoms from the carboxylate group of oxalic acid, and two nitrogen atoms（N1 and N2） from 2,2′-bipy/phen. Central vanadium atoms in complexes 1 and 2 were both in a distorted-octahedral environment, and some intermolecular hydrogen bonding linkages were also observed in each complex. Bromination reaction activity of the two complexes was evaluated with phenol red as organic substrate in the presence of H2O2, Br-and phosphate buffer, indicating that they can be considered as a potential functional model of VHPO. In addition, thermal analysis was also performed and discussed in detail.展开更多
The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG an...The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.展开更多
基金supported by the National Natural Science Foundation of China(No.200720024).
文摘The liquid-phase direct catalytic amination of benzene to aniline was performed in acetic acid water solvent using a series of vanadium （Ⅲ, Ⅳ,Ⅴ） complexes with N,O- or O,O-ligands as catalysts and hydroxylamine hydrochloride as the aminating agent. The vanadium complexes exhibited much higher selectivity towards the production of aniline than NaVO3 or VOSO4. Under the optimized conditions, an aniline yield of 42.5% and a TON of 48 with a high selectivity of above 99.9% was obtained using 0.2 mmol of [VO（OAc）2] as the catalyst.
文摘Two vanadium complexes of schiff base vith rich phenolate oxygen,o-(?)-salicylideneamino- methylphenol,had been synthesized and characterized.One is a V(Ⅳ)complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V,V)complex with an oxo bridge.The conversion between the two complexes had been discussed.
文摘Crystal structure of pyridine-2,6-dicarboxylate(dipc) vanadium complex:[(dipc)VO_2]_2( 4, 4'-bipyridine)·4H_2O(M_r=724.34) is monoclinic with space group C2/c and a=25.857(8),b=6.896(1),c=16.267(5),β=106.27(4)°,V=2784.62 D_c=1.73 g/cm￣3,F(000)=1472,Z=4.The structural solutions and refinements based on 1661 reflections (I>2σ(I))converged at R=0. 043.The coordinated number of vanadium atom is 5,the geometrical form of the five atoms are coordinated to the vanadium atom is a distorted tetragonal bipyramid of which the four coordinated atoms O(3),O(5),N(1) and O(2) make up the equatorial plane,while the other coordinated atom O(1) is to occupy the apex.
基金supported by the NNSFC(No.21401094)Project of Shandong Province Higher Educational Science and Technology Program(No.J16LC53)+1 种基金Science and the Technology Development Plans of Liaocheng(No.2014GJH01)the National College Students'Science and Technology Innovation Fund(No.1420800)
文摘A novel imidazole-functionalized dioxovanadium complex [V2O2（C2O4）（aIM）4] （aIM =1-allylimidazole） was synthesized by the reaction of VO（acac）2 with 1-allylimidazole and fully characterized by single-crystal X-ray diffraction （SCXRD）,powder X-ray diffraction （PXRD）,X-ray photoelectron spectroscopy （XPS）,Fourier transform infrared spectroscopy （FT-IR） and elemental analyses.Interestingly,the oxalate was in-situ generated from the acetylacetone anion of VO（acac）2 and further coordinated with the vanadium cation and finally complex 1 was achieved.The crystal of complex 1 belongs to the monoclinic system,space group P21/n with a =10.7922（9）,b =10.6296（8）,c =13.2936（11） （A）,μ =0.677 mm^-1,Mr =686.48,V =1516.9（2） A^3,Z =2,Dc =1.503 g/cm^3,F（000） =708,R =0.0543,and wR =0.1517 for 2459 observed reflections with Ⅰ 〉 2σ（Ⅰ）.Notably,complex 1 is further used as catalyst in the oxidation of sulfides using H2O2 as the oxidant and exhibits excellent catalytic performance （conv.up to 95.6%,sele.up to 98.9%）.
基金financially supported by the National Natural Science Foundation of China (Nos.21774006 and 21634002)。
文摘The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination method.This methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination method.The catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky effect.The vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ligand.Moreover,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.
基金Supported by the Science Foundation of Guangxi Province (No. 0342025), the Youth Science Foundation of Guangxi Province (No. 0542020) and the Teaching and Research Award Programme for Outstanding Young Teachers in Higher Education Institutions of MOE, China
文摘The mononuclear vanadium（V） complex with 2-hydroxyl-l-naphthaldehyde isonicotinoyl hydrazone was synthesized and characterized by single-crystal X-ray diffraction. The crystal is of monocfinic, space group P2 1/n with α = 10.3153（15）, b = 7.4024（11 ）, c = 24.413（4） A, β = 101.911（2）°, V= 1824.0（5） A^3, Z= 4, Mr = 427.28, Dc = 1.556 g/cm^3, F（000） = 880,μ（MoKα） = 0.591, the final R = 0.0372 and wR = 0.0926. The vanadium（V） atom adopts a distorted square-pyramidal geometry coordinated by the tridentate ligand and two oxygen atoms. The hydrogen bonds and strong π-π stacking interactions link the complex molecules into a 3-D network structure.
基金support of Ghulam Ishaq Khan Institute of Engineering Sciences and Technology
文摘A resistive-type relative humidity （RH） sensor based on vanadium complex （VO2（3-f[）） film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film of vanadium complex was coated as a humidity-sensing material on the top of the pre-patterned electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated sensing element upon adsorption/desorption of water vapor. The resistance of the humidity sensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 35%-70% RH. The overall resistance of the sensor decreases 11 times. An equivalent circuit for the VO2（3-fl） based resistive-type humidity sensor was developed. The properties of the sensor studied in this work make it beneficial for use in the instruments for environmental monitoring of humidity.
基金the Educational Commission of Henan Province (No. 14B150036)the Natural Science Foundation of Henan Province (No. 142300410252)the Key Disciplines of Analytical Chemistry of Henan Province
文摘Two hydrazone ligands （E）-N＇-（2-hydroxy-5-methoxybenzylidene）-2-hydroxybenzo- hydrazide （HLa） and （E）-N＇-（3,5-dichloro-2- hydroxybenzylidene）-4-methoxybenzohydrazide （HLb） were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone ligands, two new structurally similar vanadium（V） complexes, [VOLaL].CH3OH （1） and [vOLbL] （2）, where L is the monoanionic form of benzohydroxamic acid （HL）, were prepared and characterized by IR and UV-Vis spectra, and single-crystal X-ray diffraction. Complex 1 crystallizes as the monoclinic space group P21/n, with a = 7.5208（10）, b = 15.490（2）, c = 20.8929（18） A, β = 96.373（2）°, V = 2418.9（5） A3, Z = 4, R = 0.0831, wR = 0.2607 and GOOF = 1.061. Complex 2 crystallizes as the monoclinic space group P21/c, with a = 11.8577（18）, b = 16.468（2）, c = 12.2288（18） A, β = 106.064（2）°, V= 2294.7（6） A3, Z = 4, R= 0.0741, wR= 0.1745 and GOOF= 1.014. X-ray analysis indicates that the complexes are mononuclear vanadium （V） species, with the V atoms located in the octahedral coordination. The hydrazone ligands and the complexes were evaluated for their antibacterial （Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence） and antifungal （Candida albicans and Aspergillus niger） activities by MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide） method.
基金the GIK Institute of Engineering Sciences and Technology for its support of this work
文摘A vanadium complex （VO2（3-fl）） and CNT composite film based temperature sensor is reported in this study. Surface-type silver electrodes were deposited on the glass substrates. A thin film of VOE（3-fl） and CNT composite was coated as a temperature-sensing material on the top of the pre-patterned Ag electrodes. The temperature-sensing principle of the sensor was based on the conductivity change of the coated sensing element upon heating or cooling processes. DC and AC （100 Hz） resistances of the temperature sensor decreased quasi- linearly with increasing the temperature in the range of 25-80 ℃. The overall resistance of the sensor decreases by 1.8-2.1 and 1.9-2.0 times at DC and AC voltage, respectively. The resistance temperature coefficients of the sensor were in the range of-（0.9-1.3）% and -（1.1-1.3）% at DC and AC voltage, respectively. The properties of the sensor studied in this work, make it beneficial to be used in the instruments for environmental monitoring of temperature.
基金The work was supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China(20073048)the NSF of Fujian province for financial support
文摘The new oxovanadium (V) complex, [PyH][VO2(L)] 1 (salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L; Hpy is protonated pyridine) was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-pyridine. Similarly, another new complex, [VO(L)(OCH3)] 2 was synthesized by refluxing VOSO4 and H2L in methanol-pyridine. Crystal data for 1: C19H15N3O5BrV, Mr= 496.2, monoclinic, P21/n, a = 7.1885(3), b = 9.2718(3), c = 28.803(1) A, β = 96.185(1)°, Z = 4 and V = 1908.6(1) A3; for 2: C15H12N2O5BrV, Mr= 431.1, monoclinic, P2,/n, a = 12.202(2), b = 8.045(2), c = 16.604(3) A, β = 101.29(3)°, Z = 4 and V = 1598.4(2) A3. The structures of 1 and 2 have been determined by X-ray analyses and reveal that the coordination environments of V atoms in both complexes are of square-based pyramid. Three of the four based donor atoms are from the tridentate 'ONO' donor ligand while the fourth is one terminal oxygen atom with the V(1) - O(3) distance 1.646(4) A for 1 and one -OCH3 group with the V(1)-O(3) distance 1.753(3) A for 2. The V(1)-O(4) terminals occupy the axial sites in both cases. The complexes are also characterized by IR and 1H NMR spectroscopies.
基金supported by the Scientific Research Common Program of Beijing Municipal Commission of Education,PRC (KM200910028011)
文摘Divanadium（Ⅴ） complex [VO（aptch）（μ-OCH3）]2（1） and two monovanadium（Ⅴ） complexes [VO（apfah））（OEt）]（2a and 2b,H2aptch = 2-hydroxyacetophenone thiophene-2-car-boxylic hydrazone,H2apfah = 2-hydroxyacetophenone 2-furoic acid hydrazone） have been synthesized and characterized.Single-crystal X-ray diffraction studies reveal that 1 is a cen-trosymmetric dimer bridged by two methoxido O-atoms.Complex 1 crystallizes in the monoclinic crystal system,space groups P21/c with a = 7.4825（4）,b = 17.0928（11）,c = 11.6961（7） ,β = 98.172（4）o,Z = 2,F（000） = 728,μ = 0.829 mm-1,the final R = 0.0457 and wR = 0.1137 for 2654 observed reflections with I 〉 2（I）.The vanadium（V） is coordinated to the tridentate ligand,ethanol molecule to form a distorted square-pyramidal geometry,complexes 2a and 2b.Although 2a and 2b have the same asymmetric unit,they belong to different space groups.Complex 2a crystallizes in the monoclinic crystal system,space groups P21/n with a = 10.2293（2）,b = 15.6660（3）,c = 10.6298（2） ,β = 116.259（1）o,Z = 4,μ = 0.676 mm-1;complex 2b crystallizes in the triclinic crystal system,space groups P with a = 8.2808（4）,b = 9.4704（5）,c = 10.0819（5） ,α = 86.133（3）,= 81.956（3）,γ = 80.248（3）o,Z = 2 and μ = 0.670 mm-1.The hydrogen bonds are found to exist in 2b only.The crystal structure is stabilized by intermolecular hydrogen bonds of C-H···O.
基金supported by the Scientific Research Common Program of Beijing Municipal Commission of Education, PRC (KM200910028011)
文摘A novel vanadium（V） oxoperoxo complex [VOO2（APTCH）（CH3OH）] （HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone） has been synthesized and characterized by IR, TGA and X-ray single-crystal structure determination. The complex crystallizes in the monoclinic system, space group P21/c with a = 11.232（2）, b = 10.762（2）, c = 112.613（3）, β = 99.44（3）°, V = 1504.1（5）3, Dc = 1.657 g·cm-3, Z = 4, F（000） = 768, μ = 0.827 mm-1, the final R = 0.0392 and wR = 0.1073 for 2266 observed reflections with I 〉 2σ（I）. Single-crystal X-ray diffraction studies reveal that the vanadium（V） is coordinated by a tridentate ligand, methanol molecule and peroxo group to form a pentagonal-bipyramidal geometry. The crystal structure is stabilized by intermolecular hydrogen bonds of O-H···N and C-H···O.
基金This project is supported by NNSF of China(60172003)Specialized Research Foundations of Shandong Province(11120106).
文摘A new heteronuclear complex, dimer [(2-OH2)2Ba2(H2O)4][VO2(tpa)]24H2O (tpa: 2,4,6-tripicolinate trianion), was synthesized and structurally determined by X-ray diffraction technique where all hydrogen atoms have been located directly. The coordination geometry of V(V) ion is a distorted trigonal bipyrimid and that of Ba(II) ion is a capped square antiprism. One 2-O bridging bond and two hydrogen bonds act between the coordination geometries. A 1-D extended porous construction containing 20-member cavities is observed in the crystal.
基金The work was supported by the Science Foundation of Liaocheng University
文摘Two novel VO(IV) Schiff base complexes, VO(SALHA)2[SALHA: salicyaldehyde- oxyammonia] and VO(o-VANHA)2 [o-VANHA: o-vanillin-oxyammonia], have been synthesized with salicyaldehyde or o-vanilline, hydroxylammonium chloride and vanadyl sulfate in absolute methanol, and their crystal structures were determined by single-crystal X-ray diffraction. The vanadium(IV) centers in both complexes are five-coordinate in a distorted square pyramidal geometry. VO(SALHA)2 (C14H12N2O5V, Mr = 339.20) crystallizes in the monoclinic system, space group P21/n with a = 14.716(9), b = 7.175(5), c = 14.716(9) ? b = 113.130(7), V = 1428.8(15) 3, Z = 4, Dc = 1.577 g/cm3, l = 0.71073 ? m(MoKa) = 0.720 mm-1, F(000) = 692, the final R = 0.0466 and wR = 0.0829 for 1561 observed reflections (I > 2s(I)). VO(o-VANHA)2 (C16H16N2O7V, Mr = 399.25) is of monoclinic, space group P21/n with a = 11.386(12), b = 10.405(10), c = 14.627(15) , b = 93.654(19), V = 1729(3) 3, Z = 4, Dc = 1.533 g/cm3, l = 0.71073 , m(MoKa) = 0.615 mm-1, F(000) = 820, the final R = 0.0513 and wR = 0.1129 for 1235 observed reflections (I > 2s(I)).
基金Supported by the National Natural Science Foundation of China(No.21071071)the Education Foundation of Dalian City in China(No.2009J21DW004)
文摘Two oxo-vanadium（IV） complexes, [VO（C2O4）（2,2′-bipy）（H2O）]·C2H5OH（1） and VO（C2O4）（phen）（H2O） （2）, where 2,2′-bipy=2,2′-bipyridyl, phen=1,10-phenanthroline, were synthesized as potential functional models of vanadium haloperoxidases（VHPOs） in mixed solvent of ethanol and water at room temperature. The complexes were characterized by elemental analysis, infrared（IR）, UV-Vis and X-ray crystallography. Structural analyses showed that vanadium atom was coordinated by a terminal oxygen, one oxygen atom from coordinated water, two oxygen atoms from the carboxylate group of oxalic acid, and two nitrogen atoms（N1 and N2） from 2,2′-bipy/phen. Central vanadium atoms in complexes 1 and 2 were both in a distorted-octahedral environment, and some intermolecular hydrogen bonding linkages were also observed in each complex. Bromination reaction activity of the two complexes was evaluated with phenol red as organic substrate in the presence of H2O2, Br-and phosphate buffer, indicating that they can be considered as a potential functional model of VHPO. In addition, thermal analysis was also performed and discussed in detail.
基金supported by the Science and Technology Planning Project of Hunan Province (2012FJ3050, 2012NK3067)the 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The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.
