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1.
TiO2 nanoparticles and H2Ti2O5·H2O, Na2Ti2O4(OH)2 nanotubes were synthesized by solvothermal method and their applications in the degradation of active Brilliant-blue (KN-R) solution were investigated. The experimental results revealed that the synthesized TiO2 nanoparticles had a good crystallinity and a narrow size distribution (about 4–5 nm); the obtained H2Ti2O5·H2O, Na2Ti2O4(OH)2 were tubelike products with an average diameter of 20–30 and 200–300 nm length. The three catalysts we synthesized had some hydroxyl groups and the maximum absorption boundaries of the samples were all red-shifted, which indicated the samples had a promising prospect in photocatalysis.

The results of the photocatalytic experiments indicated that the photocatalytic activity of the samples was: TiO2 > H2Ti2O5·H2O > Na2Ti2O4(OH)2, which was in good accordance with the fact of FTIR and UV–vis absorption spectra. The formation mechanism of these nanostructures was also discussed.  相似文献   


2.
A novel N6 macrocyclic ligand, L1 (2,8,14,20-tetramethyl-3,7,15,19,25,26-hexaaza-tricyclo[19.3.1.19,13]hexacosa-1(24),9,11,13(26),21(25),22-hexaene), was obtained by reduction of the 2 + 2 condensation product of 2,6-diacetylpyridine and propane-1,3-diamine. Zinc(II) complexes of L1, of a related N8 macrocycle, L3 (3,6,9,17,20,23,29,30-octaaza-tricyclo[23.3.1.1[11,15]]triaconta-1(28),1,13,15(30),25(29),26-hexaene), similarly prepared by 2 + 2 condensation of 2,6-diformylpyridine and diethylenetriamine and of a tetra N-2-cyanoethyl derivative of a homologue of L1 prepared from diformyl pyridine and ethane-1,2-diamine, L2 (3-[6,14,17-tris-(2-cyano-ethyl)-3,6,14,17,23,24-hexaaza-tricyclo[17.3.1.18,12] tetracosa-1(23),8(24),9,11,19,21-hexaen-3-yl]-propionitrile), were prepared. Structures were determined for [ZnL1](ClO4)2 · H2O, [ZnL2](NO3)2 and [Zn2L3(NO3)2](NO3)2 · H2O. The [ZnL1](ClO4)2 · H2O and [ZnL2](NO3)2 complexes present a mononuclear endomacrocyclic structure with the metal in an octahedral distorted environment coordinated by the six donor nitrogen atoms from the macrocyclic backbone while the complex [Zn2L3(NO3)2](NO3)2 · H2O is dinuclear with both metal atoms into the macrocyclic cavity coordinated by four donor nitrogen atoms from the macrocyclic framework and one oxygen atom from one monodentate nitrate anion, in a distorted square pyramidal arrangement.  相似文献   

3.
We reported here four structures of lanthanide–amino acid complexes obtained under near physiological pH conditions and their individual formula can be described as [Tb2(dl-Cys)4(H2O)8]Cl2 (1), [Eu43-OH)4(l-Asp)2(l-HAsp)3(H2O)7] Cl · 11.5H2O (2), [Eu8(l-HVal)16(H2O)32]Cl24 · 12.5H2O (3), and [Tb2(dl-HVal)4(H2O)8]Cl6 · 2H2O (4). These complexes showed diverse structures and have shown potential application in DNA detection. We studied the interactions of the complexes with five single-stranded DNA and found different fluorescence enhancement, binding affinity and binding stoichiometry when the complexes are bound to DNA.  相似文献   

4.
Three interpenetrated polymeric networks, {[Co(bpp)(OH-BDC)] · H2O}n (1) [Ni(bpp)1.5(H2O)(OH-BDC)]n (2) and {[Cd(bpp)(H2O)(OH-BDC)] · 2H2O}n (3), have been prepared by hydrothermal reactions of 1,3-bis(4-pyridyl)propane (bpp), 5-hydroxyisophthalic acid (OH-H2BDC), with Co(NO3)2 · 6H2O, Ni(NO3)2 · 6H2O and Cd(NO3)2 · 4H2O, respectively. Single-crystal X-ray diffraction analyses reveal that the three compounds all exhibit interpenetrated but entirely different structures. Compound 1 is a fourfold interpenetrated adamantanoid structure with water molecules as space fillers, in which bpp adopts a TG conformation (T = trans, G = gauche). Compound 2 is an interdigitated structure from the interpenetrated long arms of one-dimensional molecular ladders, while bpp in 2 adopts both TT and TG conformations. Compound 3 is a twofold interpenetrated three-dimensional network from a one-dimensional metal-carboxylate chain bridged by TG conformational bpp. The hydrogen bonding interactions in 1–3 further stabilize the whole structural frameworks and play critical roles in their constructions.  相似文献   

5.
Six mononuclear complexes [M(L1)2(H2O)4] (M = Co(II), 1a and M = Mn(II), 1b), [Cu(L1)2(H2O)2] (1c), [Cu(L1)2(H2O)(Py)2] (1d), [Cu(L3)(H2O)Cl] · H2O (3a) and [Co(Sal)(H2O)(Py)3] · 2ClO4 · H2O (3b) of phenoxyacetic acid derivatives and Schiff base were determined by single crystal X-ray diffraction. The Co(II) (1a) and Mn(II) (1b) complexes are isomorphous. X-ray crystal structural analyses reveal that these coordination complexes form polymeric structure via formation of different types of hydrogen bonding and π-stacking interactions in solid. Thermal analysis along with the powder X-ray diffraction data of these complexes shows the importance of the coordinated and/or crystal water molecules in stabilizing the MOF structure. Complexes 1a, 1c, 3a show marginal catalytic activity in the oxidation of olefins to epoxides in the presence of i-butyraldehyde and molecular oxygen.  相似文献   

6.
In this paper, pyrolysis of pine wood sawdust was carried out by microwave heating at ca. 470 °C under dynamic nitrogen atmosphere. Eight inorganic additives (NaOH, Na2CO3, Na2SiO3, NaCl, TiO2, HZSM-5, H3PO4, Fe2(SO4)3) were investigated in terms of their catalytic effects on the pyrolysis. All of the eight additives have increased yields of solid products greatly and decreased yields of gaseous products more or less. Yields of liquid products have not subjected to dramatic change. The incondensable gases produced from pyrolysis consist mainly of H2, CH4, CO and CO2. All of the eight additives have made these gases evolve earlier, among which the four sodium additives have the most marked effect. All the additives have made the amount of CH4 and CO2 decrease, while all of them except NaCl, TiO2 and Fe2(SO4)3 have made that of H2 increase and all of them except Na2SiO3 and HZSM-5 have made that of CO decrease. Alkaline sodium compounds NaOH, Na2CO3 and Na2SiO3 favor H2 formation most. The most abundant organic component in the liquid products from pyrolysis of untreated sample and samples treated by all the additives except H3PO4 and Fe2(SO4)3 is acetol. All the four sodium compounds favor acetol formation reaction and the selection increasing effect follows the order of NaOH > Na2CO3 ≈ Na2SiO3 > NaCl. TiO2 goes against the formation of acetol, HZSM-5 has no marked effect on acetol formation. The two dominant organic components identified in the liquid products from pyrolysis of H3PO4 and Fe2(SO4)3 treated samples are both fufural and 4-methyl-2-methoxy-phenol. A possible pathway for acetol formation is tentatively proposed.  相似文献   

7.
The reactions of Zn(NO3)2 · 6H2O and FeSO4 · 7H2O with 4-PDS (4-PDS = 4,4′-dipyridyldisulfide) and NH4SCN in CH3OH afforded the complexes [Zn(NCS)2(4-PDS)]n (1) and [Fe(NCS)2(4-PDS)2 · 4H2O]n (2), respectively, while the reaction of CoCl2 · 6H2O with 4-PDS in CH3OH gave the complex {[Co(4-PDS)2][Cl]2 · 2CH3OH}n, (3). These complexes have been characterized by spectroscopic methods and their structures determined by X-ray crystallography. The 4-PDS ligands in 1 are coordinated to the metal centers through the nitrogen atoms to form 1-D zigzag-chains, and the distorted tetrahedral coordination geometry at each zinc center is completed by a pair of N-bonded thiocyanate ligands. Compound 2 has a 1-D channel-chain structure and each octahedral Fe(II) metal center is coordinated by four 4-PDS ligands and two trans N-bonded thiocyanate ligands. Weak SS interactions in complex 1 link the 1-D chains into 2-D molecular sheets. In complex 2, the channel chains are interlinked through SS interactions to form molecular sheets, which interpenetrate through the SS interactions to form 3-D structures with large cavities that are occupied by the water molecules. Compound 3 also has a 1-D channel-chain structure with each square-planar Co(II) metal center coordinated by four 4-PDS ligands. Multiple C–HCl hydrogen bonds and SO interactions in 3 link the 1-D chains into 2-D structures.  相似文献   

8.
Lewis acid/base addition between Ln(NO3)3 · 6H2O (Ln = Pr, Nd, Sm, Eu, Tb and Lu) and H2salen [H2salen = N,N′-ethylenebis(salicylideneimine)] gives rise to an array of coordination polymeric structures. Crystal structural analysis reveals that Salen effectively functions as a bridging ligand in these compounds. The size of the lanthanide ions controls the structures of these Salen lanthanide complexes. Two representative structures with one dimensional and two dimensional topologies, viz. [Pr(H2salen)(NO3)3(CH3OH)2]n (1) and [Ln(H2salen)1.5(NO3)3]n [Ln = Pr (2), Nd (3), Sm (4), Eu (5), Tb (6) and Lu (7)] are reported. Luminescent spectra of complexes 4 and 5 exhibit characteristic metal-centered emission lines. However, the characteristic luminescence of the terbium(III) ion is not observed either in solution or in the solid state of complex 6.  相似文献   

9.
H3PW12O40/TiO2 nanometer photocatalyst was prepared by one step hydrothermal synthesis from H3PW12O40′nH2O and Ti(OBu)4,simultaneously realizing the load and modification of H3PW12O40.The catalyst was ...  相似文献   

10.
Cationic rhodium and iridium complexes of the type [M(COD)(PPh3)2]PF6 (M = Rh, 1a; Ir, 1b) are efficient precatalysts for the hydroformylation of 1-hexene to its corresponding aldehydes (heptanal and 2-methylhexanal), under mild pressures (2–5 bar) and temperatures (60 °C for Rh and 100 °C for Ir) in toluene solution; the linear to branched ratio (l/b) of the aldehydes in the hydroformylation reaction varies slightly (between 3.0 and 3.7 for Rh and close to 2 for Ir). Kinetic and mechanistic studies have been carried out using these cationic complexes as catalyst precursors. For both complexes, the reaction proceeds according to the rate law ri = K1K2K3k4[M][olef][H2][CO]/([CO]2 + K1[H2][CO] + K1K2K3[olef][H2]). Both complexes react rapidly with CO to produce the corresponding tricarbonyl species [M(CO)3(PPh3)2]PF6, M = Rh, 2a; Ir, 2b, and with syn-gas to yield [MH2(CO)2(PPh3)2]PF6, M = Rh, 3a; Ir, 3b, which originate by CO dissociation the species [MH2(CO)(PPh3)2]PF6 entering the corresponding catalytic cycle. All the experimental data are consistent with a general mechanism in which the transfer of the hydride to a coordinated olefin promoted by an entering CO molecule is the rate-determining step of the catalytic cycle.  相似文献   

11.
The optimized structures and proton transfer reactions of 3-methyl-5-hydroxyisoxazole and its water complexes (3-M-5-HIO · (H2O)n · (n = 0–3)) were computed at B3LYP and MP2 theoretical level. The results indicates that 3-M-5-HIO has four isomers (Ecis, Etrans, K1 and K2), and the keto tautomer, and K2 is the most stable isomer in the gas phase. Hydrogen bonding between 3-M-5-HIO and the water molecules can dramatically lower the barrier by the concerted transfer mechanism. Ecis · (H2O)3 → K1 · (H2O)3 and Ecis · (H2O)2 → K2 · (H2O)2 is found to be very efficient. Comparing with the proton transfer mechanism of 5-HIO shows that the methyl substitution prevents the intramolecular proton transfer.  相似文献   

12.
采用分步沉积法制备不同Sr/Ti 摩尔比例的Sr/TiO2催化剂, 以X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、傅里叶变换红外(FT-IR) 光谱、紫外-可见漫反射光谱(UV-Vis RDS)等手段对样品进行了表征, 以可见光催化降解亚甲基蓝为模型反应考察样品光催化活性. 结果表明, 催化剂的活性和结构随Sr/Ti 摩尔比(n(Sr)/n(Ti))的变化而变化, 当n(Sr)/n(Ti)≤3/2 时, 催化剂呈由TiO2和SrTiO3组成的球状结构; 而当n(Sr)/n(Ti)在3/2 与4/1 之间时, 催化剂呈片状结构, 且随着n(Sr)/n(Ti)增大, 催化剂组成由SrTiO3 和Sr24 变为Sr24和Sr(OH)2·H2O; 当n(Sr)/n(Ti)=9/1 时, 催化剂呈以Sr(OH)2·H2O为主的针状结构. 其中, n(Sr)/n(Ti)=4/1的样品表现出最高的光催化活性, 一级反应速率为SrTiO3钙钛矿催化剂的5.0倍, 商用P25的86.7倍.  相似文献   

13.
The pure TiO2 and Fe salts [Fe(C2O4)3,5H2O]-doped TiO2 electrodes were prepared by the hydrothermal method. The pure TiO2 or Fe-doped TiO2 slurry was coated onto the fluorine-doped tin oxide glass substrate by the Doctor Blade method and then sintered at 450 ℃. The Mott-Schottks, plot indicates that the fiat band potential of TiO2 was shifted positively after Fe-doped TiO2. The positive shift of the fiat band potential improves the driving force of injected electrons from the LUMO of the dye to the conduction band of TiO2. This study shows that photovoltaic efficiency increased by 22.9% from 6.07% to 7.46% compared to pure TiO2, and the fill factors increased from 0.53 to 0.63.  相似文献   

14.
Dan Wang  Shi-Xiong Liu   《Polyhedron》2007,26(18):5469-5476
Reactions among Cu(ClO4)2 · 6H2O, Cu(acac)2/VO(acac)2 and 3-methoxysalicylaldehyde Picoloylhydrazone in different solvents give three complexes, [Cu2L(acac)(H2O)2]ClO4 (1), [Cu4L2(acac)2(py)2](ClO4)2 (2) and (VO2)2L2Cu2(acac)2 (3) (acac = acetyl acetonate and py = pyridine). There is an extended 2D structure in complex 1 constructed by hydrogen bonds between the binuclear complex cation and the ClO4 anion, and an extended 1D structure in complex 2 constructed by weak ππ stacking interactions between neighboring cyclic tetranuclear complex molecules. Complex 3 is the first oxovanadium–copper complex with a bridging oxo oxygen atom between the V atom and the Cu atom. The solid-state photoluminescent properties of the three title complexes have been studied. There is an antiferromagnetic interaction in 1.  相似文献   

15.
Sn(CH3)2Cl2 exerts its antitumor activity in a specific way. Unlike anticancer cis-Pt(NH3)2Cl2 drug which binds strongly to the nitrogen atoms of DNA bases, Sn(CH3)2Cl2 shows no major affinity towards base binding. Thus, the mechanism of action by which tinorganometallic compounds exert antitumor activity would be different from that of the cisplatin drug. The aim of this study was to examine the binding of Sn(CH3)2Cl2 with calf thymus DNA and yeast RNA in aqueous solutions at pH 7.1–6.6 with constant concentrations of DNA and RNA and various molar ratios of Sn(CH3)2Cl2/DNA (phosphate) and Sn(CH3)2Cl2/RNA of 1/40, 1/20, 1/10, 1/5. Fourier transform infrared (FTIR) and UV–visible difference spectroscopic methods were used to determine the Sn(CH3)2Cl2 binding mode, binding constant, sequence selectivity and structural variations of Sn(CH3)2Cl2/DNA and Sn(CH3)2Cl2/RNA complexes in aqueous solution. Sn(CH3)2Cl2 hydrolyzes in water to give Sn(CH3)2(OH)2 and [Sn(CH3)2(OH)(H2O)n]+ species. Spectroscopic evidence showed that interaction occurred mainly through (CH3)2Sn(IV) hydroxide and polynucleotide backbone phosphate group with overall binding constant of K(Sn(CH3)2Cl2–DNA)=1.47×105 M−1 and K(Sn(CH3)2Cl2–RNA)=7.33×105 M−1. Sn(CH3)2Cl2 induced no biopolymer conformational changes with DNA remaining in the B-family structure and RNA in A-conformation upon drug complexation.  相似文献   

16.
CdII complexes with glycine (gly) and sarcosine (sar) were studied by glass electrode potentiometry, direct current polarography, virtual potentiometry, and molecular modelling. The electrochemically reversible CdII–glycine–OH labile system was best described by a model consisting of M(HL), ML, ML2, ML3, ML(OH) and ML2(OH) (M = CdII, L = gly) with the overall stability constants, as log β, determined to be 10.30 ± 0.05, 4.21 ± 0.03, 7.30 ± 0.05, 9.84 ± 0.04, 8.9 ± 0.1, and 10.75 ± 0.10, respectively. In case of the electrochemically quasi-reversible CdII–sarcosine–OH labile system, only ML, ML2 and ML3 (M = CdII, L = sar) were found and their stability constants, as log β, were determined to be 3.80 ± 0.03, 6.91 ± 0.07, and 8.9 ± 0.4, respectively. Stability constants for the ML complexes, the prime focus of this work, were thus established with an uncertainty smaller than 0.05 log units. The observed departure from electrochemical reversibility for the Cd–sarcosine–OH system was attributed mainly to the decrease in the transfer coefficient . The MM2 force field, supplemented by additional parameters, reproduced the reported crystal structures of diaqua-bis(glycinato-O,N)nickel(II) and fac-tri(glycinato)-nickelate(II) very well. These parameters were used to predict structures of all possible isomers of (i) [Ni(H2O)4(gly)]+ and [Ni(H2O)4(sar)]+; and (ii) [Ni(H2O)3(IDA)] and [Ni(H2O)3(MIDA)] (IDA = iminodiacetic acid, MIDA = N-methyl iminodiacetic acid) by molecular mechanics/simulated annealing methods. The change in strain energy, ΔUstr, that accompanies the substitution of one ligand by another (ML + L′ → ML′ + L), was computed and a strain energy ΔUstr = +0.28 kcal mol−1 for the reaction [Ni(H2O)4(gly)]+ + sar → [Ni(H2O)4(sar)]+ + gly was found. This predicts the monoglycine complex to be marginally more stable. By contrast, for the reaction [Ni(H2O)3IDA] + MIDA → [Ni(H2O)3MIDA] + IDA, ΔUstr = −0.64 kcal mol−1, and the monoMIDA complex is predicted to be more stable. This correlates well with (i) stability constants for Cd–gly and Cd–sar reported here; and (ii) known stability constants of ML complex for glycine, sarcosine, IDA, and MIDA.  相似文献   

17.
The H2O2-based epoxidation of bridged cyclic alkenes in a monophasic system containing low concentrations (<2 mM) of [Bu4nN]4[Pr2iNH3]2H[P{Ti(O2)}2W10O38]·H2O (1) (with two η2-peroxotitanium sites in the anion) has been studied in search of the catalytically active species involved. 31P NMR spectra of 1, measured under a variety of conditions, revealed that the active species was not hydroperoxotitanium complex [P{Ti(OOH)}2W10O38]7−or [P{Ti(OOH)}Ti(O2)W10O38]7−. The reaction pathways for the alkene epoxidation are discussed to understand the kinetics (especially the initial [H2O2] dependence). It was concluded that the net catalytic reaction for the epoxidation occurred through the two-electron oxidation at the hydroperoxotitanium site in the catalyst.  相似文献   

18.
A metal-organic complex, which has the potential property of absorbing gases, [LaCu6(μ-OH)3(Gly)6im6](ClO4)6 was synthesized through the self-assembly of La3+, Cu2+, glycine (Gly) and imidazole (Im) in aqueous solution and characterized by IR, element analysis and powder XRD. The molar heat capacity, Cp,m, was measured from T = 80 to 390 K with an automated adiabatic calorimeter. The thermodynamic functions [HT − H298.15] and [ST − S298.15] were derived from the heat capacity data with temperature interval of 5 K. The thermal stability of the complex was investigated by differential scanning calorimetry (DSC).  相似文献   

19.
The compound [Zn(H2O)4]2[H2As6V15O42(H2O)]·2H2O (1) has been synthesized and characterized by elemental analysis, IR, ESR, magnetic measurement, third-order nonlinear property study and single crystal X-ray diffraction analysis. The compound 1 crystallizes in trigonal space group R3, a=b=12.0601(17) Å, c=33.970(7) Å, γ=120°, V=4278.8(12) Å3, Z=3 and R1(wR2)=0.0512 (0.1171). The crystal structure is constructed from [H2As6V15O42(H2O)]4− anions and [Zn(H2O)4]2+ cations linked through hydrogen bonds into a network. The [H2As6V15O42(H2O)]6− cluster consists of 15 VO5 square pyramids linked by three As2O5 handle-like units.  相似文献   

20.
The title calixarene, dimanganese thiacalix[4]arene tetrasulfonate, was prepared and its crystal structure was determined. [Mn(H2O)6]2[thiacalix[4]arene tetrasulfonate]·0.5H2O crystallizes in the monoclinic system, P2(1)/m space group, with a=13.014 (6), b=14.146 (9), c=13.184 (7) Å, β=113.307 (10)°, V=2229 (2) Å3 and Dc=1.710 gcm−3, Z=2. The title calixarene exists in the solid state as bilayer structure. The hydrophobic organic layer consists of thiacalix[4]arene tetrasulfonate in an up-down fashion, whereas, the hydrophilic inorganic layer consists of hexaaquamanganese (II) which is linked to the former through a second-sphere coordination.  相似文献   

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