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Materials Chemistry

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2006

Articles 61 - 87 of 87

Full-Text Articles in Chemistry

Conductivity Of Comb Polyether Pure Solid Polymer Electrolyte, Lin Ye Feb 2006

Conductivity Of Comb Polyether Pure Solid Polymer Electrolyte, Lin Ye

Journal of Electrochemistry

A comb polymer was synthesized through cationic ring-opening polymerization starting from a monomer 3-hydroxymethyl-3-methyl-oxetane.The ion conductivity was measured by CHI660A electrochemical station under various lithium salt concentrations and various temperatures.The highest ion conductivity was recorded to be 10~(-4.43)S/cm at room temperature and 10~(-3.44)S/cm at 80 ℃.DSC results showed that the segment moves more difficultly with the increasing of lithium salts concentration.XPS found the existence of aggregating lithium ions in POE5 and POE10,and it suggested that POE20 had a suitable lithium concentration for polymer electrolyte.

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Effects Of Sulfide Ions On The Inhibiting Efficiency Of Eda As A Copper Corrosion Inhibitor In Dilute Hcl Solution, Wen-Juan Qu, Rong-Gui Du Feb 2006

Effects Of Sulfide Ions On The Inhibiting Efficiency Of Eda As A Copper Corrosion Inhibitor In Dilute Hcl Solution, Wen-Juan Qu, Rong-Gui Du

Journal of Electrochemistry

The anticorrosion action of EDA on copper in dilute HCl solution and the effect of sulfide ions on the inhibiting efficiency were studied by the Tafel plot method.The corrosion potential of Cu shifted to more positive value and the corrosion current density decreased after the addition of Na_(2)S to the solution.The results indicated that sulphide ions could increase the inhibiting efficiency of EDA because of the synergistic inhibition effect between EDA and Na_2S,resulting from the adsorption of HS~(-)on the surface of Cu,facilitated the adsorption of EDA to form a highly protective adsorbed layer which prevented Cu from corrosion.

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Degradation Of Aniline Wastewater By Electro-Heterogeneous Catalysis Reactor, Wei-Li Liu Feb 2006

Degradation Of Aniline Wastewater By Electro-Heterogeneous Catalysis Reactor, Wei-Li Liu

Journal of Electrochemistry

The treatment of aniline wastewater was investigated using novel electro-heterogeneous catalysis reactor.The effects of applied cell voltage,electrolysis lime,pH value and the electrolyte on electrolysis were investigated.The experimental results show that the reactor with a cell voltage of 30 V,an electrolysis time of 1 h,pH value of 7 and a salinity of 800 mg/L can achieve the best removal efficiency on aniline,which is more efficient than the sole electrochemical reactor.

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Studies On Pva-Cmc-Koh-H_2o Alkaline Polymer Electrolytes, An-Bao Yuan Feb 2006

Studies On Pva-Cmc-Koh-H_2o Alkaline Polymer Electrolytes, An-Bao Yuan

Journal of Electrochemistry

A given amount of sodium carboxymethyl cellulose(CMC)was added to PVA complex and thus the PVA-CMC-KOH-H_(2)O alkaline polymer electrolyte with this modification was prepared.The properties of the polymer electrolyte films were characterized by AC impedance,cyclic voltammetry,differential thermal analysis and infrared spectroscopic analysis methods.The polymer electrolyte exhibited a high ionic conductivity,typically 10~(-2)S·cm~(-1) with an electrochemical stability window of about 1.6 V on stainless steel blocking electrodes.The influence of the film composition such as KOH,H_(2)O and CMC on ion conductivity was investigated.In addition,a preliminary study was carried out on the polymer electrolyte for Ni/MH battery.It was shown that the Ni/MH battery with the …

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Effects Of Srb Biofilm And Corrosion Product Films On Corrosion Behavior Of Carbon Steel, Jing Lin Feb 2006

Effects Of Srb Biofilm And Corrosion Product Films On Corrosion Behavior Of Carbon Steel, Jing Lin

Journal of Electrochemistry

Electrochemical techniques and surface analysis techniques were applied to study corrosion characteristic of A3 steel.The effects on corrosion behavior of A3 steel by sulfate-reducing bacteria(SRB)(biotic media)and corrosion product(abiotic media)were studied.The results showed that biofilms and corrosion product films play different role during different stages.Biofilms were easier flaky with increasing of its thickness.Non-uniform biofilms reduced pitting corrosion of the specimens.The corrosion product films formed under abiotic conditions were more adherently to the surface of the metal than those formed in biogenic media.

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Electrochemistry And Structures Of Silicon Surface, Gregory X.Zhang Feb 2006

Electrochemistry And Structures Of Silicon Surface, Gregory X.Zhang

Journal of Electrochemistry

Accurate control and fabrication of silicon surface structures from atomic scale to micrometer scale,which may be randomly associated with surface roughness or have well defined patterns,is critical for the per-formance and reliability of electronic devices.Electrochemical reactions of silicon in solutions involved in wetcleaning and etching of silicon wafer play an importantrole in determining the structures of silicon surface.Atre-mendous amount of researches have been done in the last several decades to understand and control a range ofcomplex electrochemical reactions at silicon/solution interface and their relations to the resulted surface struc-tures.The findings generated from these research efforts have been compiled and integrated …

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Special Photoelectrochemical Response Of Nano-Crystalline Tio_2 Electrode, Bi-Bo Lan, Jian-Zhang Zhou, Yan-Yan Xi, Hong-Xiang Chen, Guang-Hua Yao, Zhong-Hua Lin Feb 2006

Special Photoelectrochemical Response Of Nano-Crystalline Tio_2 Electrode, Bi-Bo Lan, Jian-Zhang Zhou, Yan-Yan Xi, Hong-Xiang Chen, Guang-Hua Yao, Zhong-Hua Lin

Journal of Electrochemistry

The nano-crystalline TiO_2 electrodes were prepared by spread method,electrodeposition and sol-gel method.The experimental results show that the nano-crystalline TiO_2 electrodes have special photoelectrochemical response-the photocrrent-potential curves appear peaks.The special photoelectrochemical behaviors of nano-(crystalline) TiO_2 electrodes are ascribed to nano-structure as well as special light induced redox reaction mechanism of nano-crystalline semiconductor electrodes.

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Electroless Nickel Plating On Carbon Nanotube With Non-Palladium Activation Procedure, Guang-Hui Hu, Hui-Huang Wu, Yangfang-Zu Yangfang-Zu Feb 2006

Electroless Nickel Plating On Carbon Nanotube With Non-Palladium Activation Procedure, Guang-Hui Hu, Hui-Huang Wu, Yangfang-Zu Yangfang-Zu

Journal of Electrochemistry

A new procedure of surface activation without using palladium salt was proposed for electroless nickel plating on carbon nanotubes.In the procedure,carbon nanotubes were oxidized by nitric acid and then neutralized with NaOH to create carboxyl surface groups which were used to adsorb Ni~(2+)ions,thereafter the adsorbed Ni~(2+)ions were chemically reduced into Ni nano-particles as a catalytic center for electroless nickel deposition,all these were further confirmed by infrared absorption spectra and electron microscopic observations.The results indicate that the procedure is feasible to electroless nickel plating on carbon nanotubes.The different morphology of deposits obtained from electroless plating was also discussed.

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Electro-Generated Feo_4~(2-) Using Modified Chitosan Cation Exchange Membrane, Huai-Zhen Zhong, Ri-Yao Chen, Xi Zheng, Zhen Chen Feb 2006

Electro-Generated Feo_4~(2-) Using Modified Chitosan Cation Exchange Membrane, Huai-Zhen Zhong, Ri-Yao Chen, Xi Zheng, Zhen Chen

Journal of Electrochemistry

The chitosan cation membrane was prepared by crosslinked 2% and doped with 1% H_(2)SO_(4).The products were marked as MCS.The physical properties and the ion exchange capacity of MCS were studied.Compared to the non-modified membrane,it was found that chemical modifications contributed to improving ion exchange capacity from 0.25 to 2.09 meq/g.Results was also suggested that the MCS can be used as a separator when producing sodium ferrate flocculent using electrochemical process.

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The Effect Of Solution Concentration On Properties Of Ru-Ti-Ir Oxide Anode Coatings, Wang Ke Feb 2006

The Effect Of Solution Concentration On Properties Of Ru-Ti-Ir Oxide Anode Coatings, Wang Ke

Journal of Electrochemistry

The anode coatings of Ru-Ti-Ir oxide with various solution concentrations were prepared by thermal decomposition.The scanning electron microscope(SEM),energy dispersive X-ray detector(EDX),X-ray diffraction(XRD),accelerated life,polarization curve,cyclic voltammetry and electrochemical impedance.spectroscopy(EIS)tests were carried out.The results showed that there was an obvious effect of solution concentrations on the morphology of the coatings,but little effect on polarization of chlorine evolution.Voltammetric charges and double layer capacitances of anode coatings had a tendency to fall down firstly then increase afterwards as the solution concentration increased.

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Mechanism Of Self Discharge Performance Improvement In The Ni-Mh Batteries With Naoh Electrolyte, Xiao-Feng Li Feb 2006

Mechanism Of Self Discharge Performance Improvement In The Ni-Mh Batteries With Naoh Electrolyte, Xiao-Feng Li

Journal of Electrochemistry

The self-discharge performance and charge efficiency at 60 ℃ for Ni-MH battery can be markedly enhanced by using NaOH electrolyte instead of KOH electrolyte.Both the results of electrochemical impedance spectroscopy and cyclic voltammetry tests indicate that the separation of H_2 from the negative electrode may be partly blocked in the former because of the change of the adsorption/desorption behavior of H on the surface of the negative electrode,thus results in an improvement of self-discharge performance of the battery.

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Oxygen Enrichment Effect Of Ceo_2 To The Cathode Performance Of Proton Exchange Membrane Fuel Cell, Xiang-Li Hou, Hong-Feng Xu, Jian-Hua Dong, Xin Sun Feb 2006

Oxygen Enrichment Effect Of Ceo_2 To The Cathode Performance Of Proton Exchange Membrane Fuel Cell, Xiang-Li Hou, Hong-Feng Xu, Jian-Hua Dong, Xin Sun

Journal of Electrochemistry

CeO_2 was added to Pt/C catalyst in the cathode of PEMFC by both sol and impregnation methods.The samples were evaluated by TEM,cyclic voltammogram techniques and proton exchange membrane fuel cell performance test.The addition of CeO_2 obviously improved the performance of PEMFC and represented a notable function of oxygen enrichment in the cathode side.But with the addition of CeO_2,part of the catalyst surface was covered and led to the performance drop of the PEMFC.The best content of CeO_2 is 1% when it is added by impregnation method and 3% when it is added by sol method.

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Preparation Of Spinel Limn_2o_4 Cathode Materials For Li-Ion Batteries Based On Sol-Gel Process, Xiang-Ming He Feb 2006

Preparation Of Spinel Limn_2o_4 Cathode Materials For Li-Ion Batteries Based On Sol-Gel Process, Xiang-Ming He

Journal of Electrochemistry

Spinel LiMn_(2)O_(4) was prepared from CH_(3)COOLi·2H_(2)O,Mn(CH_(3)COO)_(2) and adipic acid based on sol-gel process.XRD analysis showed that when the sintering temperature increased,the crystallinity increased,and the capacity also increased.However,its cycleability reached a maximum value at 750 ℃.The sintering duration also influenced on the capacity.The optimized performance was obtained when the sintering was carried out at 750 ℃ for 20 h.Under these conditions,as-prepared spinel LiMn_(2)O_(4) presented the initial discharge capacity of 130 mAh g~(-1) and 125 mAh g~(-1) at 15~(th) cycle.

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Electrocatalytic Oxidation Of Glucose On Nano Pt/C Electrode, Cui-Lian Chen Feb 2006

Electrocatalytic Oxidation Of Glucose On Nano Pt/C Electrode, Cui-Lian Chen

Journal of Electrochemistry

Nano Pt/C electrocatalysts were prepared by intermittent microwave heating method.The electrooxidation of glucose on smooth Pt and～Pt/C electrodes has been studied and compared.The results showed that the electrochemical properties on nano Pt/C were improved due to the reduction of the overpotential and the increase in the kinetic rate.The surface area would be significantly increased when the particle size of the catalyst was reduced to nano-scale,resulting in the increase in the activity.The enhancement in the resistance to poisoning could be explained that the oxygen-containing species are easier to react with poisoning species on nano Pt/C and re-active the electrode.

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Potential Distributions On External Tank Bottom Under Cathodic Protection Of Deep Well Anode, Yan-Xia Du, Guo-Zhong Zhang, Gang Liu Feb 2006

Potential Distributions On External Tank Bottom Under Cathodic Protection Of Deep Well Anode, Yan-Xia Du, Guo-Zhong Zhang, Gang Liu

Journal of Electrochemistry

Potential distributions of deep well anodic electric field on external tank bottom were derived according to the basic law of electromagnetic field and the geometry characteristics of cathodic protection system.Making use of electric field superposition principle,considering the action of anodic and cathodic electric fields,the potential distributions on external tank bottom under the protection of deep well anode were studied.The calculated results were compared and agred well with the measured data.

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The Complex Of Pasp And Tungstate As Inhibitors Of Cupronickel B10′S Corrosion In 3% Nacl Solution, Qun-Jie Xu Feb 2006

The Complex Of Pasp And Tungstate As Inhibitors Of Cupronickel B10′S Corrosion In 3% Nacl Solution, Qun-Jie Xu

Journal of Electrochemistry

AC impedance and polarization curve measurements were conducted to study the effects of environ-ment-friendly inhibitors PASP,Na_(2)WO_(4)and their complexes on the corrosion of cupronickel B10 in 3%NaCl solution.The results indicate that PASP or Na_(2)WO_(4)alone does inhibit the corrosion of B10,and most effectiveconcentrations are 40 mg/L and 60 mg/L for PASP and Na_(2)WO_(4),respectively.With the total concentration of 40mg/L for the complex inhibitors,the optimum complex ratio of PASP to Na_(2)WO_(4)was 3:1.The complex of such a combination showed a significantly synergetic inhibition effect on the corrosion of B10.

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Electrochemical Reduction Behavior Of Benzaldehyde In The Ionic Liquids, Ning Zhao, Wen-Ju Dong Feb 2006

Electrochemical Reduction Behavior Of Benzaldehyde In The Ionic Liquids, Ning Zhao, Wen-Ju Dong

Journal of Electrochemistry

In this paper,the electrochemical reduction of benzaldehyde was investigated in C_4MIMBF_(4)、(C_(6)MIMBF_(4)) and C_(8)MIMBF_(4) ionic liquids by cyclic linear sweep voltammetry,cyclic square-wave voltammetry and chronocoulometry.Benzaldehyde exhibits two successive one-electron irreversible reduction(E_(P1)=-1.39 V,E_(P2)=1.69 V) with GC electrode in C_(4)MIMBF_(4),the voltammetric data for benzaldehyde give diffusion coefficients of 1.5 10~(-8)cm~(2)/s and 1.3 10~(8)cm~2/s.There is one current peak in C_(6)MIMBF_(4)and C_8MIMBF_4 ionic liquids due to their stronger alkalinity then C_4MIMBF_4.The decay time of the charging current became longer in C_(4)MIMBF_(4)、C_(6)MIMBF_(4)、C_(8)MIMBF_(4),and slower heterogeneous kinetics in(C_(6)MIMBF_(4)) and C_(8)MIMBF_(4) ionic liquids.

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2006 National Conference On Corrosion Electrochemistry And Measuring Methods Feb 2006

2006 National Conference On Corrosion Electrochemistry And Measuring Methods

Journal of Electrochemistry

No abstract provided.

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Posterminaries: Plain Text, Alexander H. King Jan 2006

Posterminaries: Plain Text, Alexander H. King

Alexander H. King

You just can’t win an argument with an English professor.

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Gold Nanoparticles Propulsion From Surface Fueled By Absorption Of Femtosecond Laser Pulse At Their Surface Plasmon Resonance, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed Jan 2006

Gold Nanoparticles Propulsion From Surface Fueled By Absorption Of Femtosecond Laser Pulse At Their Surface Plasmon Resonance, Wenyu Huang, Wei Qian, Mostafa A. El-Sayed

Wenyu Huang

Femtosecond laser irradiation of assembled nanoprisms on a quartz substrate at their strong absorbing surface plasmon resonance frequency causes their propulsion from the substrate. SEM and AFM show that the particles fly while keeping their prismatic shape, but they decrease in size by an amount that can be calculated assuming atomic sublimation. Several mechanisms are mentioned, but the sublimation mechanism, which rapidly builds up pressure under the particle and propels it away from substrate, is discussed in detail. From the kinetic energy given to the flying nanoparticle, an initial velocity of ∼160 m/s (∼360 miles/h) is calculated. The dependence of …

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Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman Jan 2006

Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman

Alexander H. King

Thermal effects on domain orientation in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) have been investigated by using in situ x-ray diffraction with an area detector. In the case of a soft PZT, it is found that the texture parameter called multiples of a random distribution (MRD) initially increases with temperature up to approximately 100 °C and then falls to unity at temperatures approaching the Curie temperature, whereas the MRD of hard PZT and PT initially undergoes a smaller increase or no change. The relationship between the mechanical strain energy and domain wall mobility with temperature is discussed.

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Solid-Solid Phase Transformation Via Internal Stress-Induced Virtual Melting, Significantly Below The Melting Temperature. Application To Hmx Energetic Crystal, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, Blaine W. Asay Jan 2006

Solid-Solid Phase Transformation Via Internal Stress-Induced Virtual Melting, Significantly Below The Melting Temperature. Application To Hmx Energetic Crystal, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, Blaine W. Asay

Valery I. Levitas

We theoretically predict a new phenomenon, namely, that a solid−solid phase transformation (PT) with a large transformation strain can occur via internal stress-induced virtual melting along the interface at temperatures significantly (more than 100 K) below the melting temperature. We show that the energy of elastic stresses, induced by transformation strain, increases the driving force for melting and reduces the melting temperature. Immediately after melting, stresses relax and the unstable melt solidifies. Fast solidification in a thin layer leads to nanoscale cracking which does not affect the thermodynamics or kinetics of the solid−solid transformation. Thus, virtual melting represents a new …

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Nmr Studies Of Lysozyme Surface Accessibility By Using Different Paramagnetic Relaxation Probes, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Luisa Bracci, Angela Pui-Ling Tong, Wing-Tak Wong, Neri Niccolai Jan 2006

Nmr Studies Of Lysozyme Surface Accessibility By Using Different Paramagnetic Relaxation Probes, Andrea Bernini, Ottavia Spiga, Vincenzo Venditti, Filippo Prischi, Luisa Bracci, Angela Pui-Ling Tong, Wing-Tak Wong, Neri Niccolai

Vincenzo Venditti

Paramagnetic probes, whose approach to proteins can be monitored by nuclear magnetic resonance (NMR) studies, have been found to be of primary relevance for investigating protein surfaces' accessibility. Here, a Gd(III) neutral complex which contains two metal ions, [Gd2(L7)(H2O)2], is suggested as a paramagnetic probe particularly suited for systematic NMR investigation of protein surface accessibility, due to an expected high relaxivity and to the lack of electric charge which could favor specific interactions. Hen egg white lysozyme has been used as a model system to verify the absence of preferential approaches of this paramagnetic probe to specific protein moieties by …

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Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin Jan 2006

Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin

Chemistry Faculty Publications

We report in detail the preparation of two substituted terephthalic acids: 2‐sulfomethylterephthalic acid (1) and 2‐phosphonoterephthalic acid (2). Efficient, short syntheses have been developed for both compounds. They are potentially useful monomers for construction of acid‐pendant polymer chains.

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Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin Jan 2006

Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin

Chemistry Faculty Publications

We are presenting the preparation, characterization and density functional theory (DFT) studies {B3LYP/6-31+G(d)) of several reiated classes of N-nitrosocarbamates and N-nitrosoureas. The iong-range goal is the design and preparation of compounds, which would undergo photochemical or hydrolytic decomposition, to yield stabilized cyclic cations that can serve as alkylating agents at various nucleophilic centers, including DNA bases.

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A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond Jan 2006

A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond

Articles

A neutral 2-site chloride selective compound has been developed (3), based on a 1,3- alternate tetrasubstituted calix[4]arene providing a preorganised supramolecular scaffold. The resultant supramolecular cavity is amongst the first to combine urea functional groups bridged with single methylene spacers to pyrene moieties. It combines a naturally and synthetically proven H-bonding system with the elegant ratiometric fluorescent signalling properties of an intramolecular pyrene excimer system, triggered by conformational changes upon anion coordination. The excimer emission of 3 is quenched, with a simultaneous rise in the monomer emission solely by the chloride anion amongst a wide variety of anions tested. 3 …

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Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond Jan 2006

Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond

Articles

The current work is amongst the first to examine the potential usefulness of the nitrile functional group in potentiometric analytical sensors for soft metals. Nitrile functionality has hereby been incorporated into a calix[4]arene skeleton to give a series of new cation selective hosts. The analytical sensing behaviour of these hosts was examined by Ion Selective Electrode (ISE) based potentiometry. In all cases a preference for soft metals was observed, explained primarily in terms of soft–soft compatibility between calix[4]arene nitrile hosts and metal guests in combination with a classical ‘lock and key’ best fit mechanism. Hosts 2, 3 and 4 showed …

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