bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methanol electrooxidation on smooth platinum modified with Ru: The influence of Ru coverage and potentials on oxidative current and products
Authors: Wang Hong‐Sen 
Published: September 2010

AbstractMethanol oxidation on smooth Pt electrode modified with different coverage of Ru was studied using cyclic voltammetry and potential step combined with differential electrochemical mass spectroscopy. The current efficiency of formed CO2 was calculated from faraday current and ion current of m/z = 44. The results show that Ru modified Pt electrode with the coverage of ca. 0.3 has the highest catalytic activity for methanol electrooxidation, i.e. faraday current and the current efficiency of CO2 at the low potentials reach to the maximum. In addition, Ru loses its co‐catalytic properties at the high potentials.
Influences of the hydrophobicity of the heme‐binding pocket on the properties and functions of cytochrome b5 mutants
Authors: Gan Jian‐Hua , Wang Yun‐Hua , Wu Jian , Huang Zhong‐Xian , Xia Zong‐Xiang 
Published: September 2010

AbstractThe mutation sites of the four mutants F35Y, P40V, V45E and V45Y of cytochrome b5 are located at the edge of the hemebinding pocket. The solvent accessible areas of the “pocket interior” of the four mutants and the wild‐type cytochrome b5 have been calculated based on their crystal structures at high resolution. The change in the hydrophobicity of the heme‐binding pocket resulting from the mutation can be quantitatively described using the difference of the solvent accessible area of the “pocket interior” of each mutant from that of the wild‐type cytochrome b5. The influences of the hydrophobicity of the heme‐binding pocket on the protein stability and redox potential are discussed.
Sterols from the fungus Catathelasma imperiale
Authors: Yang Sheng‐Ping , Xu Jun , Yue Jian‐Min 
Published: September 2010

AbstractEight ergostane‐type sterols and three their derivatives (one mono‐linoleate and two mono‐glucosides) were isolated from the ethyl acetate soluble fraction of the fungus Catathelasma imperiale. Two of them are novel compounds, namely 22E, 24R‐ergosta‐7,22‐diene‐3β,5α‐diol‐6β‐inoleate (1) and 22E,24R‐ergosta‐7,22‐diene‐3β,5β,6α‐triol (5) with an uncommon cis‐fused A/B ring. Structures of these compounds were demonstrated on the basis of their chemical evidences and spectroscopic methods, especially 2D NMR techniques.
Novel photo‐induced coupling reactions of 9‐fluorenylidene‐malononitrile or 1,1‐diphenyl‐2,2‐dicyanoethylene with 10‐methyl‐9,10‐dihydroacridine. A study on the photophysics of the reaction
Authors: Jiang Hong , Liu Yon‐Cheng , Wang Guan‐Wu , Wu Li‐Zhu , Tung Chen‐Ho 
Published: September 2010

Abstract9‐Fluorenylidenemalononitrile (FDCN) or 1, 1‐diphenyl‐2,2‐dicyanoethylene (DPCN) reacted with 10‐methyl‐9,10‐dihydroacridine (AcrH2) under irradiation (λ 320 nm) to give couping products. In order to gain further insight into the mechanism of the photo‐induced reaction, the photophysics of the reactions of FDCN or DPCN with AcrH2 have been investigated by using UV‐vis spectroscopy, fluorescence spectroscopy, excitation spectroscopy and time‐resolved fluorescence spectroscopy, respectively. The results show that FDCN or DPCN interacts with AcrH2 in the ground states to form a charge transfer complex, which further reacts to give the coupling product upon. irradiation.
Investigation of Chemiluminescence with Electrogenerated Reagents and Its Analytical Application
Authors: Zhang Zhu‐Jup , Li Bao‐Xin , Zheng Xing‐Wang 
Published: September 2010

AbstractIn this paper, studies on chemiluminescence (CL) systems with electrogenerated reagents, including BrO−, CIO−, Br2, [Cu‐(HIO6)2]5‐, H2O2, Mn3+, Co3+ and Ag2+, are described. The analytical applications of the CL system with electrogenerated reagents are reviewed.
A Quick Estimate of the Correlation Energy for Alkanes
Authors: Li Shu‐Hua , Li Wei , Ma Jing 
Published: September 2010

AbstractWithin the localized molecular orbital description, the intra‐and interorbital pair correlation energies calculated with the coupled cluster doubles (CCD) theory have been obtained for methane, ethane, propane, butane, isobutane, pentane, isopentane and neopentane using the 6–31G* basis set. The results showed the quantitative transferability of pair correlation energies and gross orbital correlation energies within this series of molecules. Based on the gross orbital correlation energies of five sample alkanes (butane, isobutane, pentane, isopentane and neopentane), we have derived a simple linear relationship to estimate the CCD correlation energy for an arbitrary large alkane. The correlation energy predicted by this simple relationship remarkably recovers more than 98.9% of the exact CCD correlation energy for a number of alkanes containing six to eight carbon atoms. The relative stability of less branched isomers can be correctly predicted.
NaA Zeolite Membrane with High Performance Synthesized by Vapor Phase Transformation Method
Authors: Cheng Zhi‐Lin , Chao Zi‐Sheng , Lin Hai‐Qiang , Wan Hui‐Lin 
Published: September 2010

AbstractNaA zeolite membrane was synthesized with high permeance on porous alumina substrate by the vapor phase transformation method. The membranes were characterized by XRD and SEM techniques. The XRD results showed that the membranes after the synthesis time of 24 h consisted of the pure NaA zeolite crystals. The SEM results showed that the membranes after the synthesis time of 48 h consisted of intergrown zeolite crystals. The H2 permeance of the NaA zeolite membranes was higher than 2.0 × 10−6 mol/(Pa · m2 · s), and the maximum of the gas H2/C3H8 permselectivity was 7.15, which is higher than the corresponding Knudsen diffusion selectivity of which is 4.69.
Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Difluoroamine Complex
Authors: Ju Xue‐Hai , Xiao He‐Ming , Xia Qi‐Ying 
Published: September 2010

AbstractAb initio calculations were carried out for difluoroamine complexes at the HF and MP2 levels with different basis sets. The BSSE correction was included with counterpoise procedure. The dimer, trimer and tetramer were all found to exhibit two minima. The corrected binding energies are ‐8.87, ‐19.19 and ‐33.81 kJ · mol−1 at the MP2/6–311G* *//HF/6–311G* * level for the more stable dimer, trimer and tetramer, respectively. At the G2 level, the binding energy for the cyclic dimer is ‐10.86 kJ · mol−1. There are two types of complexes: cyclic and chain. The contribution of cooperative effect to the interaction energy is up to 12.9% of the binding energy in the cyclic complexes, but negligible in the chain ones. There exist weak hydrogen bonds which involve six and eight F H contacts at ca. 0.23–0.24 nm in the cyclic trimer and cyclic tetramer, respectively. The intermolecular interaction is an exothermic process under 400.0K accompanied by a decrease in the probability.
Dinuclear Pentacarbonyl Tungsten Complex Bridged by Bis (3,5‐dimethylpyrazol‐1‐yl) methane
Authors: Zhao Xue‐Mei , Tang Liang‐Fu , Yang Pan , Wang Ji‐Tao 
Published: September 2010

AbstractA new bis (pyrazol‐1‐yl) methane ligand, [Ph2 (HO) CCH (3,5‐Me2Pz)2, Pz= pyrazole] (1), with a bulky substituent on the methine carbon atom has been successfully synthesized by the reaction of bis(3,5‐dimethylpyrazol‐1‐yl) methyllithium with benzophenone. Treatment of this ligand with W(CO)6 under UV‐irradiation in THF at room temperature afforded a novel dinuclear complex CH2[3,5‐Me2PzW(CO)5]2 (2) with loss of the Ph2CO fragment, which was characterized by IR, 1H NMR spectra and elemental analyses as well as the X‐ray single crystal diffraction analysis. This compound crystallizes in the or‐thorhombic space group Pbcn, with a = 1.7690(3) nm, b = 1.4460 (3) nm, c = 1.2994 (2) nm, Z = 4, V = 3.3239 (10) nm3, Dc = 1.775 g · m−3, μ = 6.967 mm−1, F (000) = 1672, R1 = 0.0414 and wR2 = 0.0988. Bis(3,5‐dimethylpyrazol‐l‐yl) methane acts as a bridging bidentate ligand in this complex, which links two W(CO)5 fragments. In addition, heating this complex under reflux in 1,2‐dimethoxyethane (DME) gives the known chelated mononuclear complex CH2(3,5‐Me2Pz)2‐W(CO)4 (3).
Palladium‐Catalyzed Addition of Carbon Monoxide and Carbon Tetrachloride to 1‐Octene in Supercritical Carbon Dioxide
Authors: Zhang Qun‐Jian , Sun Jun‐Hua , Jiang Huan‐Feng , Ouyang Xiao‐Yue , Cheng Jin‐Sheng 
Published: September 2010

AbstractThe Pd‐catalyzed addition of carbon monoxide and carbon tetrachloride to 1‐octene gave coadduct [alkyl 2‐(2, 2, 2‐trichloroethyl)octanoate] as the major product in supercritical carbon dioxide by using pyridine as the base. It was found that the selectivity and the yield of coadduct were greatly affected by the pressure of carbon dioxide, the reaction temperature and the amounts of alcohol and base used.
Synthesis of Novel Anionic Receptors with (Thio) urea and Amide Binding Sites and the Recognition Properties for Anions
Authors: Wu Jin‐Long , Wei Lan‐Hna , Zeng Zhen‐Ya , Liu Shun‐Ying , Gong Rui , Meng Ling‐Zhi , He Yong‐Bing 
Published: September 2010

AbstractTwo new neutral receptors (1 and 2) containing (thio) urea and amide groups were synthesized by simple steps in good yields. The binding properties for anions of 1 and 2 were characterized by UV‐vis and fluorescence spectra. Receptor 1 had an excellent selectivity for AcO− in comparison with other anions. The association constants of 1 · AcO− and 2 · p‐NO2PhOPO23− were higher than those of other anions (Cl−, Br−, I−, H2PO−4 and p‐NO2PhO−). In particular, an obvious color change was observed from light yellow to golden yellow upon addition of AcO− to the solution of 1 in DMSO. The results of non‐linear curve fitting by UV‐vis and fluorescence spectral data indicate that a 1:1 stoichiometry complex is formed between compound 1 or 2 and anions through a hydrogen bonding interaction.
Prediction on Critical Micelle Concentration of Nonionic Surfactants in Aqueous Solution: Quantitative Structure‐Property Relationship Approach
Authors: Wang Zheng‐Wu , Huang Dong‐Yang , Gong Su‐Ping , Li Gan‐Zuo 
Published: September 2010

AbstractIn order to predict the critical micelle concentration (cmc) of nonionic surfactants in aqueous solution, a quantitative structure‐property relationship (QSPR) was found for 77 nonionic surfactants belonging to eight series. The best‐regressed model contained four quantum‐chemical descriptors, the heat of formation (ΔH), the molecular dipole moment (D), the energy of the lowest unoccupied molecular orbital (ELUMO) and the energy of the highest occupied molecular orbital (EHOMO) of the surfactant molecule; two constitutional descriptors, the molecular weight of surfactant (M) and the number of oxygen and nitrogen atoms (nON) of the hydrophilic fragment of surfactant molecule; and one topological descriptor, the Kier & Hall index of zero order (KH0) of the hydrophobic fragment of the surfactant. The established general QSPR between Ig(cmc) and the descriptors produced a relevant coefficient of multiple determination: R2 = 0.986. When cross terms were considered, the corresponding best model contained five descriptors ELUMO. D, KH0, M and a cross term nON · KH0, which also produced the same coefficient as the seven‐parameter model.
Synthesis, Structure and Optical Limiting (OL) Properties of a Novel Incomplete Cubane‐like Cluster [PPh4] [(η5‐C5Me5) WS3‐(CuBr) (Cul)2 (μ‐dppm)]
Authors: Yu Hong , Xu Qing‐Feng , Ji Shun‐Jun , Lang Jian‐Ping , Sun Zhen‐Rong 
Published: September 2010

AbstractReaction of [PPh4][η5‐C5Me5)WS3] with Cul, CuBr and bis‐(diphenylphosphino)methane (dppm) (molar ratio = 1:2:1:1) in MeCN gave rise to [PPh4][(η5‐C5Me5)WS3 (CuBr)(Cul)2‐(μ‐dppm)] (1) in high yield. Compound 1 crystallizes in the monoclinic, space group P21/n with lattice parameters: a = 1.2906(4) nm, b = 1.5006(8) nm, c = 3.1484(6) nm, β = 92.12(2)°, V = 6.093(3) nm3, Z = 4. The structure of the anion of 1 contains an incomplete WS3Cu3 cubane‐like core in which two Cul units are bridged by a dppm ligand. The W‐Cu distances vary in the range of 0.2644(1)–0.2793(1) nm. The optical limiting (OL) properties of 1 in MeCN were measured with the laser pulse‐width of 12‐ns at 532 nm, and the nanosecond OL effect may be due to the reverse saturable absorption (RSA) related to the excited triplet states.
A New Triterpenoid Saponin and a New Glycoside from Epigynum aurilum
Authors: Cao Jian‐Xin , Lai Guo‐Fang , Wang Yi‐Fen , Yang Liu‐Bing , Luo Shi‐De 
Published: September 2010

AbstractA new triterpenoid saponin with novel sugar moiety (1), a new trisaccharide derivative (2), as well as a known monosaccharide derivative (3), were isolated from the dried stem of Epigynum aurilum. The structures of compounds 1 and 2 were determined by MS and NMR spectram analyses.
A Novel Proton Sensor with Luminescence and Color Signaling Based on Platinum(II) Terpyridyl Acetylide Complex
Authors: Yang Qing‐Zheng , Wu Li‐Zhu , Wu Zi‐Xin , Zhang Li‐Ping , Tung Chen‐Ho 
Published: September 2010

AbstractA novel sensitive probe for proton based on platinum(II) terpyridyl acetylide complex by monitoring the changes both in luminescence and color is described.
Synthesis and Crystal Structure of a Puckered Rhombus Grid‐like Coordination Polymer with Bridging Ligand Containing Sulfanyl Linker
Authors: Han Lei , Luo Jun‐Hua , Hong Mao‐Chun , Wang Rui‐Hu , Lin Zheng‐Zhong , Cao Rong 
Published: September 2010

AbstractA new coordination polymer with sulfide moieties, [Co(ptmb)2] · 0.25H2O (ptmb=4–(4‐pyridylthiomethyl)‐benzoate), was synthesized by self‐assembly of Co(NO3)2 · 6H2O with Hptmb under solvothermal conditions. X‐ray single crystal diffraction study shows that it is a 2D layer structure consisting of puckered rhombus grid with dimensions 1.175 nm ×1.110 nm.
Hydrothermal Synthesis and Properties of Open‐Framework Mixed‐valence Iron Phosphates Fe2lll Fell1.5(PO4)3 with Three‐dimensional Structure
Authors: Duan Li‐Ying , Liu Fu‐Chen , Wang En‐Bo , Li Yang‐Guang , Hu Chang‐Wen , Xu Lin 
Published: September 2010

AbstractThe open‐framework iron phosphate Fe2lllFe1.5ll,(PO4)3 was hydrothermally synthesized and characterized by elemental analysis, IR, EPR, XPS and single crystal X‐ray diffraction analysis. The title compound crystallized in the triclinic, space group P1 with a=0.64724(4) nm, b=0.79651(6) nm, c=0.94229(5) nm, a= 104.447(2)°. β= 108.919(4)°. y= 101.741(4)°, V=0.42302(5) nm3, Z= 1 and RI (wR2)=0.0307 (0.0793). Crystal data were collected on a Rigaku R‐AXIS RAPID IP diffractometer with Mo Ka (γ=0.071073 nm) at 293(2) K in the range of 2.43°<Õ <27.46°. The structure of 1 consists of 19 non‐hydrogen atoms including three and a half crystallographically independent Fe and three P atoms. Fe(1) connects its symmetrical Fe(1A) through bridging oxygen forming a dimer and the dimers are connected by Fe(4) forming an infinite staircase‐like chain. Fe(2) and Fe(3) connect the infinite chains into a layer with bridging oxygen. Layers are interconnected via Fe(4) forming the six‐membered and eight‐membered channel systems.
Synthesis and Crystal Structure of a Two‐dimensional Silver(I)‐Iron(III) Heteronuclear Coordination Polymer: {[Ag,Fe2(SCN)12(H2O)2] [(inaH)2(H2O)2]}n
Authors: Li Xiu‐Ling , Tong Ming‐Liang , Niu De‐Zhong , Chen Jiu‐Tong 
Published: September 2010

AbstractThe 2‐D heteronuclear coordination polymer {[Ag4Fe2(SCN)12(H2O)2] (inaH)2(H2O)2}n(1) (inaH is the abbreviation of protonated isonicotinic acid) with chemical formula C24Ag4Fe2N14O8S12has been synthesized and characterized by single crystal X‐ray diffraction, elemental analysis and IR spectroscopy. The Ag2S2rings connect two kinds of octahedral geometries of Fe(III) ions, [Fe(NCS)6]3–and Fe(H2O)2(NCS)4]−units with bridging thiocyanate ions leading to 2‐D [Ag4Fe2(SCN)12(H2O)22–anion framework. Four kinds of rings including the unprecedented thirty‐two membered Ag4Fe4(SCN)8rings share comers or edges in the 2‐D anion layer structure. All thiocyanates coordinate to the metal ions according to the HSAB principle with N atoms binding to the Fe(III) ions and with S atoms binding to Ag(I) ions. Pronoated ina cations stabilize the layer structure as counter ions and hydrogen bonds were formed within the pronoated in a cations dimer and between the dimers and the lattice waters. Crystal data:Mr=1560.44, triclinic,P1,a=0.76082(1) nm, b=0.9234 nm, c= 1.85611(4) nm,a=103.0170(10)°, β=93.7780(10)°,y=97.4080(10)°,V= 1.25385(3) nm3, Z=1, μ(Mo Kα)=2.650 mm−1,Dc,=2.067 g · cm−3,F(000)=758,R1=0.0412. wR2=0.1003.
Analysis of the Nucleoside Content of Cordyceps sinensis Using the Stepwise Gradient Elution Technique of Thin‐layer Chromatography
Authors: Ma King‐Wah , Chau Foo‐Tim , Wu Jian‐Yong 
Published: September 2010

AbstractNucleoside is the main class of active components in Cordyceps sinensis. Thin‐layer chromatography (TLC) is one of the most commonly used methods in pharmacopoeias for analyzing chemical components of herbal medicine. Since the isocratic elution method cannot be applied successfully in TLC analysis for separating all the nucleoside components, the stepwise gradient elution has been developed in this work to separate eight nucleoside standards with success. In this way, quantitative analyses of the samples of Cordyceps sinensis were achieved via the proposed TLC procedure coupled with the scanning densitometric techniques of CAMAG and TLCQA methods for qualitative and quantitative analysis.
Synthesis and Crystal Structure of Di‐n‐butyltin(IV) Complex with 2‐Oxo‐propionic Acid (4‐Pyridinecarbonyl) Hydrazone
Authors: Liu Hong‐Wen , Lu Wen‐Guan , Tao Jia‐Xun 
Published: September 2010

AbstractThe novel complex di‐n‐butyltin(IV) 2‐oxo‐propionic acid (4‐pyridinecarbonyl) hydrazone, (n‐C4H9)2Sn‐[O2CC(CH3)=N‐N=C(‐O)C5N‐4] (H2O) has been synthesized and its structure has been determined by X‐ray diffraction analysis. The complex crystallizes in orthorhombic system with space groupPca21. Crystal data:a=2.7540(9) nm,b=0.9676(3) nm,c=1.5750(5) nm, V=4.197(2) nm3,Dc=1.444 g/cm3, Z=8. μ= 1.241 mm−1.F(000)= 1856,R1=0.0462 andwR2=0.1001. In the crystals of the title complex, the tin atom is in six‐coordination with a distorted octahedral geometry, three oxygen atoms [O(1), O(3) and O(4)] and one nitrogen atom N(1) forming the equatorial plane and C(10)‐Sn(1)‐C(14) being the axis. Two molecules form a dimer with weak interactions of Sn‐O bonding and hydrogen bonds.
An Alternative Method for Anomeric Deacetylation of Per‐acetylated Carbohydrates
Authors: Li Ying‐Xiae , Li Yu‐Wen , Zhaivg Wei , Guan Hua‐Shi 
Published: September 2010

AbstractAn alternative method for anomeric deacetylation of fully acetylated carbohydrates has been developed using imidazole in methanol.
Crystal Structure and Thermal Decomposition Mechanism of [K(DNP)(H2O)0.5]
Authors: Ma Gui‐Xia , Zhang Tong‐Lai , Zhang Jian‐Guo , Shao Bing , Li Yu‐Feng , Song Jiang‐Chuang , Yu Kai‐Bei 
Published: September 2010

AbstractThe new coordination polymer, [K(DNP)(H2O)0.5]n(DNP=2, 4‐dinitrophenol) was prepared by the reaction of 2,4‐dinitrophenol with potassium hydroxide. The molecular structure was determined by X‐ray single‐crystal diffraction analysis, FT‐IR techniques, and elemental analysis. The crystal is monoclinic, space group C(2)/c with the empirical formula of C6N2O5.5K, Mr=231.21. The unit cell parameters are as follows: a=2.0789(3) nm, b= 1.2311(2) nm. c=0.7203(1) nm. β=109.611(15)°, V=1.7366(4) nm3, Z=4. 0, = 1.769 g/cm3, F(000)=936, μ (Mo Kα) =0.617 mm−1. The potassium ions coordinate with all the oxygen atoms of phenolic hydroxyl group and nitro‐group of different 2,4‐dinitrophenol (DNP) ligands with high coordination number, and form a god cross‐linked three‐dimensional net structure of which makes the complex with god stabilities. The thermal decomposition of [K(DNP)(H2O)0.5]n has only an intense exothermic process in the temperature range of 338–343 °C corresponding to a mass loss of 75.029s. The final decomposition residue is potassium isocyanide.
Synthesis, Crystal Structure and Magnetic Property of Sanwich‐Type Heteropolyoxometalate Na9[(Na(H2O),}3{Cu(H20)}3(BiW9O33)2] 42H2O
Authors: Xue Gang‐Lin , Wang Hu‐Lin , Xie Zhi‐Hai , Shi Qi‐Zhen , Wang Ji‐Wu , Wang Da‐Qi 
Published: September 2010

AbstractThe heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33) 42H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3 · 5H2O with CuCl2 · 2H2O at pH≠6. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are: a = 1.410(3) nm, b=2.338(5) nm, c=3.173(6) nm, β=98.06(4)°. V= 10.354(35) nm3. monoclinic crystal system, space group: C2/c, Z = 4, R1= 0.0471. wR2 = 0.0642 I>2σ(I)]. R1= 0.1371, wR2 = 0.0868 (all data). [(Na(H2O)2}3{Cu(H2O)}3W9O33)2]9– has D34 symmetry. IR, UV‐vis spectra, TG curve and magnetic property of the complex were also discussed. The compound exhibits an antiferromagnetic coupling with J= ‐8.08 cm−1 and g =2.21.
Study on Syntheses and Anti‐bacterial Activities of Some New Transition Metal Complexes with Schiff Base Ligand Containing Pyridine and Amide Moieties
Authors: Li Mei‐Ying , Hu Pei‐Zhi , Zhu Jun‐Cheng , Liu Yi , Xu Kuo‐Xi 
Published: September 2010

AbstractSeveral new transition metal complexes using Schiff base containing pyridine and amide moieties (N, N′ ‐bis(ß‐salicylaliminoethyl)‐2, 6‐pyridinedicarboxylic amide, H1L) as the ligand have been prepared. Their compositions and structures are corroborated by elemental analysis. IR, W, 1H NMR, DTA‐TG and molar conductivity data. Their anti‐bacterial activities have been studied by microcalorimetry. The result shows that the ligand and all complexes are potential anti‐bacteria reagent and their inhibitory capacities are concentration‐depended. The Mn complex has the strongest inhibitory capacity.
Direct Electrochemical Oxidation of NADPH at a Low Potential on the Carbon Nanotube Modified Glassy Carbon Electrode
Authors: Chen Jing , Cai Chen‐Xin 
Published: September 2010

AbstractNADPH can be directly oxidized on a carbon nanotube modified glassy carbon (CNT/GC) electrode in phosphate buffer solution (pH=6.0) with a diminution of the overpotential of more than 700 mV. The anodic peak currents increase linearly with the increase of concentration of NADPH in the range of 5×10−‐1 to 1×10−‐1 mom with a detection limit of about 1×10−‐1 mol/L. The CNT/GC electrode exhibits high sensitivity, low potential and stability in detecting NADPH and thus might be used in biosensors to study the electrocatalytic reaction of important de‐hydrogenase‐based biological systems.
Fluorometric Investigation of the Acid‐Base and Complexation Behaviour of Tetracycline and Oxytetracycline
Authors: Li Hong‐Xia , Zhang Jun‐Jie , He Xi‐Wen , Li Guo‐Jiang 
Published: September 2010

AbstractThe widely used antibiotics tetracyclines have been effectively used for ailing heart attack, ulcer cure and gene therapy. The actual mechanism of their activity has been proposed to link with the complexes with many metal ions. However, the sites at which complex formation takes place are not well established. In the present work, the deprotonation sequence of tetracycline (TC) and oxytetracycline (OTC), and their specific group used to bind europium ion were investigated by examining the character of fluorescence of TC and OTC as well as that of their complexes. It was concluded that the site of complexation is coordinated with the deprotonation sequence changing with the acidity/basicity of the solution. And it was inferred that five hydrogens in TC and OTC could be dissociated. The deprotonation sequence is as follows: C(3) hydroxy, C(10) phenol, C(4) dimethylamine, C(12) hydroxy and C(12a) hydroxy. The corresponding complexation site changed with pH increase in solution as follows: C(2) acylamino and C(3) hydroxy moiety, C(10)‐C(11) ketophenol moiety, C(4) dimethylamine and C(3) hydroxy moiety, C(11)‐C(12) β‐diketone moiety, C(12) hydroxy and C(12a) hydroxy moiety, and C(12) hydroxy and C(1) ketone moiety respectively.