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Using unmodified Au nanoparticles as colorimetric probes for TNT based on their competitive reactions with melamine

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Chinese Chemical Letters 2014年第9期25卷 1271-1274页

作者： Xiao-Dong Xia Hao-Wen Huang key laboratory of theoretical chemistry and molecular simulation Minister of EducationSchool of Chemistry and Chemical EngineeringHunan University of Science and Technology

Gold nanoparticles （Au NPs） can serve as visualized colorimetric probes for various targets and modification-free sensing strategies are preferred. The donor-acceptor interaction between the electron-rich melamine （MA） and the electron-deficient trinitrotoluene （TNT） allows formation of a supramolecule in aqueous solution. Melamine alone makes the initially individual reddish Au NPs aggregate into gray/blue Au NP assemblies due to melamine forming multiple ligand sites toward the Au NPs. Interestingly, the preformed supramolecule of MA-TNT disenables aggregation of the Au NPs. Therefore the unmodified Au NPs provide facile colorimetric probes for TNT detection in aqueous solution. Rapid identification of TNT is established by naked eye inspection. By using spectrophotometer tools, quantification of TNT is accomplished with a linear range of 80μmol L-1 to 1.2 mmol/L-1 and a limit of detection （LOD） of 27μmol/L^-1. In contrast to previous strategy with surface-modified Au NPs, here a modification-free sensing strategy for TNT assay has been developed with greater convenience, rapidity, and cost-effectiveness.

关键词： Electron donor-acceptor interaction Gold nanoparticles Melamine Trinitrotoluene Colorirnetry

Tuning plasmon absorption of unmodified silver nanoplates for sensitive and selective detection of copper ions by introduction of ascorbate

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Chinese Chemical Letters 2014年第10期25卷 1403-1406页

作者： Xiao-Dong Xia Tian-Lun Wang Xiao-Yuan Yuan key laboratory of theoretical chemistry and molecular simulation Minister of EducationSchool of Chemistry and Chemical EngineeringHunan University of Science and Technology

Silver nanoplates as novel optical sensors for Cu^2＋ detection have been *** nanoplates are synthesized via previous H_2O_2-NaBH_4 cyclic oxidation-reduction *** introduction of ascorbate as mild reductants,Cu^2＋ ions are reduced into Cu~＋ and the Cu^＋ is further reduced to Cu,which is deposited on the surface of the silver *** deposition of the Cu on the surface of the silver nanoplates allows a significant red-shift of their plasmon ***,trace Cu^2＋ can be *** shift of the plasmon absorption wavelength of silver nanoplates is proportional to the Cu^2＋concentration over a range of 40-340 μmol L^（-1） with a limit of detection of 9.0 μmol L^（-1）.Moreover,such silver nanoplate-based optical sensors provide good selectivity for Cu^2＋ detection,and most other metal ions do not disturb its ***,the practicality of the proposed sensor was *** Cu^2＋assay is advantageous in its simplicity,selectivity,and cost-effectiveness.

关键词： Silver nanoplate Plasmon absorption Wavelength shift Optical sensor Copper ions Ascorbate

Benchmark Calculations on the Atomization Enthalpy,Geometry and Vibrational Frequencies of UF_6 with Relativistic DFT Methods

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Chinese Journal of Structural chemistry 2008年第8期27卷 967-974页

作者：肖海李隽 Institute of theoretical and Computational chemistry Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education Tsinghua UniversityBeijing 100084 China

Benchmark calculations on the molar atomization enthalpy, geometry, and vibrational frequencies of uranium hexafluoride （UF6） have been performed by using relativistic density functional theory （DFT） with various levels of relativistic effects, different types of basis sets, and exchange-correlation functionals. Scalar relativistic effects are shown to be critical for the structural properties. The spin-orbit coupling effects are important for the calculated energies, but are much less important for other calculated ground-state properties of closed-shell UF6. We conclude through systematic investigations that ZORA- and RECP-based relativistic DPT methods are both appropriate for incorporating relativistic effects. Comparisons of different types of basis sets （Slater, Gaussian, and plane-wave types） and various levels of theoretical approximation of the exchange-correlation functionals were also made.

关键词： UF6 atomization enthalpy relativistic effect density functional theory

Synthesis of Novel Spiro Thiazolo[3,2-a][1,3,5]triazines via 1,3-Dipolar Cycloaddition of Azomethine Ylide

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Chinese Journal of chemistry 2011年第1期29卷 97-101页

作者： Li, Xiaofang Liu, Haochong Zheng, Aiting Li, Zhikui Li, Guobin Yu, Xianyong Yi, Pinggui key laboratory of theoretical chemistry and molecular simulation of ministry of education Hunan Province College Key Laboratory of QSAR/QSPR School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan Hunan 411201 China

The 1,3-dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and acenaphthenequinone to 7-arylmethylidene-3-aryl-3,4-dihydro-2H-thiazolo[3,2-aJ[1,3,5]triazin-6（7H）-ones afforded novel dispiro[acenaphthylene-1,2’-pyrrolidine]-3＇,7″-[1,3]thiazolo[3,2-a][1,3,5]triazines in moderate yields. The structures of the products were determined and characterized thoroughly by NMR, MS, IR, elemental analysis and X-ray crystallographic analysis. The results of experiment indicated that this 1,3-dipolar cycloaddition proceeded with high stereoselectivity and regioselectivity.

关键词： thiazolo[3,2-a]triazine 1,3-dipolar cycloaddition azomethine ylide spiroheterocycle

Unexpected 1,3-Dipolar Cycloaddition Reaction of Thiazolo[3,2-a]pyrimidine Derivatives and Nitrilimine

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Chinese Journal of chemistry 2011年第4期29卷 741-744页

作者：李筱芳刘浩冲刘彬郑爱庭李国斌于贤勇易平贵 key laboratory of theoretical chemistry and molecular simulation of ministry of education Hunan Province College Key Laboratory of QSAR/QSPR School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan Hunan 411201 China

The 1,3-dipolar cycloaddition reactions of nitrilimine with thiazolo[3,2-a]pyrimidine derivatives was investigated. Bis-cycloadducts were obtained through a domino 1,3-dipolar cycloaddition/ring-opening/ring-opening/ 1,3-dipolar cycloaddition processes. The structures of the products were characterized thoroughly by NMR, IR, MS, elemental analysis together with X-ray crystallographic analysis.

关键词： 1,3-dipolar cycloaddition thiazolo[3,2-a]pyrimidine nitrilimine reaction mechanism synthesis

theoretical Study of Structure, Energetic, Hydrogen Bonds Strength and Intramolecular Proton Transfer of 2-（2-R （R=OH, NH2, SH） Phenyl （or Pyridyl）） Benzoxazoles （or Benzothiazoles）

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Chinese Journal of chemistry 2011年第4期29卷 650-654页

作者：易平贵彭洪亮汪朝旭于贤勇李筱芳梁永宏 key laboratory of theoretical chemistry and molecular simulation of ministry of education Hunan Province College Key Laboratory of QSAR/QSPR School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan Hunan 411201 China

The ground- and excited-state intramolecular proton transfer processes of 2-（2-R （R=OH, NH2, SH） phenyl （or pyridyl）） benzoxazoles （or benzothiazoles） are investigated by the DFT methods. The calculated results indicate that in the ground state there is a high correlation （R=0.9950） between the proton transfer barrier and the intramolecular hydrogen bonds （IMHB） strength. The increase of the strength of IMHB in the proton transfer processes leads to a larger barrier contributions. Intramolecular proton transfer process pathway is along with the minimal difference of change value in the IMHB angle. In the excited-state, there is a similar relationship between the IMHB and the bartier.

关键词： density functional calculations intramolecular proton transfer hydrogen bonds benzoxazole benzothiazole

Novel nanoporous palladium catalyst for electroreduction of hydrogen peroxide

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Rare Metals 2011年第4期30卷 332-336页

作者： YI Qingfeng NIU Fengjuan School of chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan 411201 China key laboratory of theoretical chemistry and molecular simulation （ministry of education of China） Hunan University of Science and Technology Xiangtan 411201 China

Titanium-supported nanoporous palladium catalyst （Pd/Ti） was prepared by a hydrothermal method using PdC12 as a precursor, ethylenediamine tetraacetic acid （EDTA） as a ligand, and formaldehyde as a reduction agent. Complex Pd-EDTA^2- is favorable for the formation of Pd particles with nanoscale sizes. The electroactivity of the Pd/Ti catalyst towards the electroreduction of hydrogen peroxide in 1 mol/L NaOH solution was evaluated by voltammetric techniques. Both linear scan voltammetric and chronoamperometric data present significantly large steady-state reduction current density of the hydrogen peroxide electroreduction on the prepared Pd/Ti catalyst. The results show that the prepared Pd/Ti catalyst is an effective electrocatalyst for the electroreduction of hydrogen peroxide in alkaline media.

关键词： electrocatalysis nanoporous materials palladium hydrogen peroxide fuel cells

Crystal structures and theoretical investigation of anti-/syn-2,4-diphenylpentane-and 2,4-di-p-tolylpentane-2,4-diols

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Journal of Central South University 2012年第5期19卷 1219-1225页

作者：焦银春曹晨忠赵小林 School of chemistry and Chemical Engineering Central South University School of chemistry and Chemical Engineering Hunan University of Science and Technology key laboratory of theoretical chemistry and molecular simulation of ministry of education Hunan University of Science and Technology

2,4-diphenylpentane- and 2,4-di-p-tolylpentane-2,4-diols were investigated employing experimental and density functional theory （DFT） method at B3LYP/6-31G （d） level. The structure of syn-2,4-di-p-tolylpentane-2,4-diol （2b） was characterized by X-ray diffraction and compared with the crystal structures of anti- and syn-2,4-diphenylpentane-2,4-diols （la and lb）. X-ray diffraction indicates that inter and intra-molecular hydrogen bonds are formed in the crystal structures. There is n-n staking interaction in lb and 2b. Good linear correlations and similar results are found between the experimental 1H and 13C NMR chemical shifts （6~exp） and GIAO （Gauge Independent Atomic Orbital） method calculated magnetic isotropic shielding tensors （acalc）. HOMO and LUMO molecular orbitals were calculated at the same levels with the different results. UV-vis absorption spectra of the compounds were recorded in EtOH, MeCN, n-BuOH and cyclohexane with different dielectric constants. It is found that the solvent effect is obvious when e is 24.85（EtOH）, 35.69（MeCN） and it is weak when e is decreased to 17.33（n-BuOH）, 1.18 （cyclohexane）.

关键词： X-ray crystallography hydrogen bonds nuclear magnetic resonance (NMR) density function theory (DFT) UV-visabsorption solvent effect

Investigation on two triphenylene based electron transport materials

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Science China chemistry 2019年第6期62卷 775-783页

作者： Minghan Cai Chongguang Zhao Dongdong Zhang Xiaozeng Song Lian Duan key laboratory of Organic Optoelectronics and molecular Engineering of ministry of education Department of ChemistryTsinghua University

Promoting electron mobility is the key to designing high performance electron transport materials(ETMs). Formation of intermolecular interaction can be helpful to enhance their electron mobilities as a result of more ordered molecular ***, to reveal the inherent influence of intermolecular π-π stacking on the electron mobilities, we designed two ETMs, namely,2,4-diphenyl-6-[3-(2-triphenylenyl)phenyl]-1,3,5-triazine(TPTRZ) and 2,4-diphenyl-6-[4′-(2-triphenylenyl)[1,1′-biphenyl]-3-yl]-1,3,5-triazine(TPPTRZ). Thermal, photophysical and electrochemical measurement results indicate they are good ETM candidates. Additionally, TPTRZ and TPPTRZ exhibit high electron mobilities of 3.60×10^(-5) and 3.58×10^(-5) cm^2V-1 s^(-1), respectively, at an electric field of 7×10~5 V cm^(-1). By taking X-ray single crystal structure, theoretical calculation and time of flight(TOF) results into consideration, it is revealed that strong intermolecular π-π stacking induced by planar triphenylene and triphenyltriazine units renders TPTRZ and TPPTRZ small energetic and positional disorder parameters, and results in their high electron mobilities thereby. By further enhancing intermolecular π-π stacking, ETMs with even higher electron mobilities can thus be anticipated.

关键词： organic light-emitting diode electron transport material electron mobility π-π stacking intermolecular interaction