bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Study of the Dissolution of Some Atomic and Diatomic Species in the Square and Hexagonal 2‐D Helium Lattices
Authors: Zanjanchi Farzaneh , Sabzyan Hassan
Published: May 2015

Dissolution of some industrially relevant atomic and diatomic species (Ar, Ne, H, O, H2, N2 and O2) in the 5 × 5 2‐D hexagonal and square helium lattices, as the model of the liquid helium cryogen, has been studied using ab initio MP2/6‐31++G computations. Structural, electronic and thermochemical properties have been calculated and analyzed for these solution lattices. Results of these calculations show that dissolution of Ar, Ne, H and H2 species is more favored at higher temperatures. A reverse trend is observed for the dissolution of O, N2 and O2 species. A staggered orientation is preferred by all diatomic species in both lattices. Results of this study also show that breakage of the O2 molecule becomes slightly easier in the 2‐D helium lattices as compared with that of the H2 molecule. Effect of the cavity geometry and size, and position of the solute in the lattice have also been studied. Analysis of the results shows that the range of the interaction between the solute and solvent atoms is only one helium layer.
Simple and Sensitive Electrochemiluminescence Method for Determination of Bisphenol a Based on its Inhibitory Effect on the Electrochemiluminescence of Luminol
Authors: Zhuang Ya‐Feng , Zhang Jin‐Tao , Cao Gui‐Ping
Published: May 2015

An electrochemiluminescence inhibition method has been developed for the determination of bisphenol A based on studying the inhibition phenomena of bisphenol A to the electrochemiluminescence of luminol. There is a linear relationship between the inhibitive intensity of electrochemiluminescence and the concentration of bisphenol A in the range of 4.4 × 10−7 to 2.2 × 10−5 mol/l. The method was successfully applied to the determination of bisphenol A in hot water in contact with commercially available table‐water bottle samples.
Reaction HFCO + 2H2O — Calculated Mechanisms
Authors: Tsai Wu‐Hung , Ho Jia‐Jen
Published: May 2015

Three possible reaction mechanisms of methanoyl fluoride with 2H2O include a concerted and a stepwise hydrolysis of HFCO into HCOOH + HF, and a pure catalytic decomposition of HFCO into HF + CO. Among these, the two H2O molecules acting as catalyst to decompose HFCO has the lowest calculated barrier, 25.1 kcal/mol with respect to the reactant‐adduct complex, whereas the barriers for the concerted and stepwise hydrolytic reactions in which one H2O acts as a reactant and the other H2O as catalyst are similar, 30.8 kcal/mol for concerted and 29.9 kcal/mol for stepwise. The formation of transoid HCOOH in the hydrolysis of HFCO is more favorable than cisoid HCOOH.
Study on the Liquid‐Solid Flotation Separation of Cadmium by Ammonium Sulfate‐Potassium Iodide‐Cetylpyridine Chloride‐Water System
Authors: Tu Chang‐Qing , Wen Xin‐Rong
Published: May 2015

The liquid‐solid flotation separation behaviors of Cd2+ in ammonium sulfate‐potassium iodide‐cetylpyridine chloride‐water system and the conditions for the separation of Cd2+ from other metal ions were studied. The results showed that in the presence of 1.0 g (NH4)2SO4 and when the dosage of 0.1 M potassium iodide was 2.0 mL and 0.01 M cetylpyridine chloride (CPC) solution was 1.0 mL respectively, the formed water‐insoluble ternary association complex of KI‐CPC‐Cd floated above water phase and liquid‐solid phases were formed with clear interface. In this condition, Zn2+, Mn2+, Fe2+, Co2+, Ni2+ and Al3+ could not be floated and Cd2+ was floated quantitatively at pH 5.0. Therefore, the quantitative separation of Cd2+ from the above metal ions could be achieved. The quantitative flotation separation determination of Cd2+ in the sample of synthetic water and industrial waster water was performed, and the results agreed well with those by AAS method. The recoveries were 97.2%∼102.4%, and the RSD was 1.8%.
Trace Determination of Benzalkonium Chlorides in River and Wastewater by Capillary Electrophoresis following Solid‐Phase Extraction Coupled with Salting‐Out Extraction
Authors: Liu Hsueh‐Ying , Ding Wang‐Hsien
Published: May 2015

Trace levels analysisbenzalkonium chlorides (BAKs) in river water and wastewater treatment plants (WWTP) effluents were determined by capillary electrophoresis (CE) following solid‐phase extraction (SPE) and salting‐out extraction. Salting‐out extraction using an appropriate ratio of sodium chloride (NaCl) and acetonitrile (ACN) mixed with concentrated SPE elutant was capable of providing more than 500‐fold enhancement in detection sensitivity. The ratios of ACN and NaCl for salting‐out extraction were investigated and optimized. Matrix interference was eliminated by salting‐out extraction. Limits of quantitation of BAK homologues were achieved at 0.1 μg/L in 250 mL water samples. Recoveries of BAKs in various spiked water samples ranged from 70% to 84% with relative standard deviation (RSD) less than 9%. Trace amounts of total BAKs were detected in river water and WWTP effluent samples ranging from 27 to 145 μg/L at the first time by CE.
Preparation and Photocatalytic Activity of TiO2 Films on Silica Glass Substrates by Assembly Technique
Authors: Chen Ru‐Fen , Zhang Cui‐Xuan
Published: May 2015

Nanostructured TiO2 coating films on silica glass substrates were prepared by the assembly technique. TiO2 colloids were synthesized employing the sol‐gel method using TiCl4 as a precursor. The effect on the surface structures which was caused by the polyethylene glycol (PEG) added to the precursor solution and the photocatalytic activity were studied. The experimental results showed that the cobble‐like TiO2 coating films were synthesized at 500 °C. On the surface of the samples, TiO2 films exhibited uniform shape and a narrow size distribution. The result of proper PEG added to the precursor solution led to the decreasing of the size of TiO2 particles and the increasing of the surface area of the samples. The photocatalytic activity of TiO2 films with PEG was higher than that of samples without PEG.
Membrane Transport of Pb(II) with a Cooperative Carrier Composed of Dibenzyldiaza‐18‐Crown‐6 and Palmitic Acid
Authors: Kazemi Sayed Yahya
Published: May 2015

A chloroform membrane system containing a given mixture of dibenzyldiaza‐18‐crown‐6 and palmetic acid was applied for transport of Pb2+ ions. The transport was capable of moving metal ions “uphill”. Thus, it was possible to follow the transfer of Pb(II) from the aqueous source phase to the organic layer and from the organic layer to the receiving phase. The effects of thiosulfate concentration in the receiving phase, palmetic acid and dibenzyldiaza‐18‐crown‐6 concentration in the organic phase on the efficiency of the transport system were examined. By using S2O32− ion as metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is 96 ± 1.5%. The selectivity and efficiency of lead transport from aqueous solution containing Cu2+, Tl+, Ag+, Co2+, Ni2+, Mg2+, Zn2+, Hg2+, Cd2+, Ca2+ were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of Ag+ and Cu2+ were diminished drastically.
Extractive Spectrophotometric Methods for Determination of Clarithromycin in Pharmaceutical Formulations Using Bromothymol Blue and Cresol Red
Authors: Shah Jasmin , Jan M. Rasul , Manzoor Suraya
Published: May 2015

Two simple and sensitive extractive spectrophotometric methods have been described for the analysis of clarithromycin in pure form and in pharmaceutical formulations. The methods involved formation of yellow colored chloroform extractable ion‐association complexes of clarithromycin with bromothymol blue (BTB) and cresol red (CR) in buffered aqueous solution at pH 4. The extracted complexes showed maximum absorbance at 410 and 415 nm for BTB and CR, respectively. Beer's law is obeyed in the concentration ranges 0.1–20 μg mL−1 and 2.0–20 μg mL−1 of clarithromycin with molar absorptivity of 2.01 × 104 and 4.378 × 103 for BTB and CR, respectively. The composition ratio of the ion‐association complex was clarithromycin: BTB and CR = 1:1 as established by Job's method. The methods have been applied to the determination of drug in commercial formulations. The results of analysis were validated statistically and through recovery studies.
New Approaches for the Synthesis of Thiazoles and Their Fused Derivatives with Antimicrobial Activities
Authors: Wardkhan Wagnat W. , Youssef Mohamed A. , Hamed Faten I. , Ouf Salama A.
Published: May 2015

The 2‐ethoxy carbonyl methylene thiazol‐4‐one (3) reacts with acetophenone (4) to give the ethyl 2‐(4‐oxo‐4,5‐dihydro‐thiazol‐2‐yl)‐3‐phenyl‐2‐butenoate (5). The reactivity of the latter product towards aromatic aldehydes 6a‐d, cyanomethylene reagents 9a,b, aromatic aldehydes 13a‐d, phenylisothiocyanate (16), elemental sulfur and aromatic amines (20a‐c) was studied to give arylidene, pyridine, thiophene and anilide derivatives. Some of the newly synthesized derivatives were used to synthesize fused derivatives. The antimicrobial activities of the newly synthesized products were tested in vitro for antimicrobial activity against two bacterial isolates, one saprophytic (Escherichia coli) and the other parasitic (Xanthomonas citri) and for antifungal activity against one saprophytic (Aspergillus fumigatus) and two phytopathogenics (Rhizoctonia solani and Fusarium oxysporum).
A Novel Method for the Synthesis of 4(3H)‐Quinazolinones
Authors: Jing Xiao‐Bi , Li Zhen , Pan Xin , Shi Yao‐Cheng
Published: May 2015

Different metal perchlorates were screened to catalyze the three‐component reaction of anthranilic acid, triethyl orthoformate and amines to afford quinazolin‐4(3H)‐ones in solvent‐free conditions. Ni(ClO4)2 or Zn(ClO4)2 was demonstrated to be efficient to catalyze the reaction.
Convenient, Easy and Highly Regioselective Preparation of Haloalcohols from the Reaction of Epoxides with Elemental Halogen Catalyzed by Hexamethylenetetramine (HMTA)
Authors: Naeimi Hossein
Published: May 2015

The highly regioselective cleavage of epoxides into corresponding vicinal haloalcohols with elemental halogen has been catalyzed by hexamethylenetetramine (HMTA). This method occurred under neutral and mild conditions with high yields and short reaction times in various aprotic solvents even when sensitive functional groups were present.
Effect of Indole‐3‐Acetic Acid Analogs on the Differentiation of HL‐60 Cells
Authors: Lien Jin‐Cherng , Jiang Yu‐Dong , Chen Chun‐Jen , Kuo Sheng‐Chu , Huang Li‐Jiau
Published: May 2015

In continuing search for novel cell differentiation agents, a series of derivatives of indole‐3‐acetic acid and indole‐3‐carboxylic acid were prepared and tested against HL‐60 cells for their differentiation and antiproliferation activities. Among them, N‐ethyl‐1‐benzylindole‐3‐carboxamide (14) was the most potent, whereas N‐methyl 1‐benzylindole‐3‐acetamide (5) and N‐methyl 1‐benzylindole‐3‐carboxamide (13) synergistically potentiated with all‐trans‐retinoic acid to induce cell differentiation as well as antiproliferation. Our results indicate that these compounds are effective cell differentiation and antiproliferation agents in combination with retinoic acid.
A New Set of Amino Acid Descriptors for the Development of Quantitative Sequence‐Activity Modelings of HLA‐A*0201 Restrictive CTL Epitopes
Authors: Liang Gui‐Zhao , Shu Mao , Li Sheng‐Shi Zl.
Published: May 2015

A new set of amino acid descriptors, SZOTT (Scores of Zero dimension, One dimension, Two dimension, Three dimension) was derived from principal component analysis on a matrix of 1369 descriptors including 0D, 1D, 2D and 3D information of 20 coded amino acids. SZOTT scales were then employed to represent structures of HLA‐A*0201 restrictive CTL epitopes, and further, quantitative sequence‐activity modelings (QSAMs) were constructed based on partial least squares and back‐propagation artificial neural networks. Satisfying results show that structural information related to biological activities of HLA‐A*0201 restrictive CTL epitopes can be preferably represented by SZOTT scales, which may be a useful structural representation technique for study of QSAMs of peptides.
The One‐Pot Synthesis of 2,4,5‐Triaryl‐Imidazoles Using Heteropolyacids as Heterogeneous and Recyclable Catalysts
Authors: Heravi Majid M. , Sadjadi Samaheh , Oskooie Hossein A. , Hekmatshoar Rahim , Bamoharram Fatemeh F.
Published: May 2015

2,4,5‐triaryl imidazoles were obtained in high yields with excellent purity from the condensation of benzaldehydes, NH4OAc and 1,2‐diketone in the presence of a catalytic amount of various heteropolyacids (HPAs).
Hypervalent Iodine(III) Sulfonate Mediated Synthesis of α‐Thiocynanatoketones in a Task‐Specific Ionic Liquid [bmim]SCN
Authors: Huang Hsin‐Yu , Wang Huey‐Min , Hou Rei‐Sheu , Cheng Hui‐Ting , Chen Ling‐Ching
Published: May 2015

The task‐specific ionic liquid (TSIL) and 1‐n‐butyl‐3‐methylimidazolium thiocynanate, ([bmim]SCN) were used as the medium as well as the reactant for the synthesis of α‐thiocynanatoketones by the reaction with α‐sulfonyloxy aryl ketones. Significant rate enhancements and improved yields have been observed.
Trimethylsilylation of Hydroxyl Group with 1,1,1,3,3,3‐Hexamethyldisilazane (HMDS) Catalyzed by Tribromomelamine (TBM)
Authors: Ghorbani‐Choghamarani Arash , Zolfigol Mohammad Ali , Hajjami Maryam , Jafari Shila
Published: May 2015

Tribromomelamine (TBM) can be used as a novel catalyst for the trimethylsilylation of alcohols and phenols with 1,1,1,3,3,3‐hexamethyldisilazane (HMDS). A wide variety of hydroxyl groups were selectively protected in CH2Cl2/CH3CN under mild conditions.
Plasmonic Properties and Size Programming: A Quantitative Study for Photosynthesized Gold Nanoparticles
Authors: Ou Chun‐Chang , Yeh Hui‐Wen , Chang Fang‐Yi , Yang Chung‐Sung
Published: May 2015

A novel two‐component peak quantitative spectra deconvolution model is employed to elucidate the relationship between the plasmonic properties and the concentration‐dependent Au nanocrystals nucleation. The reactions with the initial concentration of starting reagent NaAuCl4 from 0.75 mM to 0.1 mM are monitored. The peak area variation between component peak (b), large size nanoparticles (d ≥ 8.1 nm), and component peak (a), small size nanoparticles (d ≤ 8.0 nm), demonstrates that the initial concentration of NaAuCl4 plays a decisive factor to determine the (b/a) ratio, i.e. the growth progresses of Au nanoparticles. If the initial concentration of NaAuCl4 is higher than 0.2 mM, two independent growth progresses of Au nanoparticles are observed, and a continuous λmax blue‐shift of surface plasmon absorption peak accompanied with the second growth progress is measured. On the other hand, in the reactions with the initial concentration of NaAuCl4 lower than 0.2 mM, only one crystal growth progress of Au nanoparticles is shown, and the blue‐shift phenomenon of absorption peak induced by the second crystal growth progress no longer exists.
Synthesis of Nano‐Sized Zinc Oxide Photocatalyst by Combustion Method
Authors: Lin Cheng‐Shiung , Hwang Chyi‐Ching
Published: May 2015

The objective of this research was to use combustion synthesis to create a nano‐sized ZnO photocatalyst using citric acid as the fuel and zinc nitrate as the oxidant. The starting materials were mixed in a stoichiometric ratio, and a slurry precursor with high homogeneity was formed. The precursor was ignited at room temperature, resulting in dry, loose, and voluminous ZnO powders. The powders, characterized by SEM, TEM and XRD, showed a particle size range of 40 to 80 nm with a wurtzite structure. The ZnO powders were introduced as a photocatalyst for the degradation of methyl orange, which was adopted as a model compound. UV light (6W) was used as the irradiation source to induce synthesized ZnO powders to perform catalytic activity. The photocatalytic reaction was executed in 40 mL of a 10 ppm methyl orange aqueous solution under 254 nm UV illumination. In this work, it was observed that both UV light and ZnO powders are needed for the photocatalytic reaction. In addition, it was found that increasing the amount of ZnO powder present in the MO (methyl orange‐C14H14N3NaO3S) solution did not correlate directly with an increase in photocatalytic ability. It was found that the scattering problem of UV light also needs to be considered. The optimized photocatalytic degradation ratio in this work reached 92.7%.
Theoretical Study of Heterocyclic Nitro Compounds for Use as Novel Explosives and Propellants
Authors: Ju Xue‐Hai , Wang Zun‐Yao , Qiu Ling
Published: May 2015

The heats of formation (HOFs) of heterocyclic nitro compounds were obtained by using a density functional theory B3LYP method with 6‐31G* and 6‐311+G** basis sets. The isodesmic reactions designed for the evaluation of HOFs keep most of the basic ring structures of the title compounds and thus ensure the credibility of the results. The values of HOFs are 567.90, 874.29 and 975.83 kJ/mol at the B3LYP/6‐31G* level for hexanitrohexazaadamantane (A), nonanitrononaza‐tetracyclo[7.3.1.13,7.15,11] pentadecane (B) and tetranitrotetrazacubane (C) respectively. The predicted detonation velocities of the title compounds are larger than, and detonation pressures are much larger than that of the widely used 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX). The dissociation energy for the weakest C‐N bonds in the cage skeleton of the title compounds are 137‐144 kJ/mol at the B3LYP/6‐31G* level.
Synthesis and Fluorescent Properties of 2‐Arylamino‐5‐(3‐Aryl‐1‐Phenyl‐Pyrazol‐4‐Yl)‐1,3,4‐Thiadiazoles
Authors: Li Cun‐Kui , Cao Ling‐Hua
Published: May 2015

A series of novel pyrazolyl‐substituted 1,3,4‐thiadiazole derivatives (6a‐6d, 7a‐7d, 8a‐8d) were prepared by cyclization of the intermediate 3‐aryl‐l‐phenyl‐pyrazol‐4‐ylformaldehyde 4′‐phenylthiosemicarbazones with 0.5 M ferric chloride solution. The structures of the new compounds were confirmed by IR, 1H NMR and elemental analysis. Simultaneously, the compounds were detected by fluorescence spectrophotometer and had preferable fluorescence activity.
Synthesis of 3‐Aryl‐2,5‐Dihydro‐1‐Benzoxepines from Phenol via Ring‐Closing Metathesis
Authors: Tsai Jui‐Chi , Li Sie‐Rong , Chen Liang‐Yeu , Chen Po‐Yuan , Joung Jia‐Ying , Shu Chung‐Jung , Lo Yu‐Fuan , Lin Chun‐Nan , Wang Eng‐Chi
Published: May 2015

In this paper, the synthesis of 3‐aryl‐2,5‐dihydro‐1‐benzoxepines is described. While the reaction was started from phenol and based on the sequential reactions such as Claisen rearrangement, O‐alkylation, Wittig reaction, and ring‐closing metathesis (RCM), a series of new 3‐aryl‐1‐benzoxepines were prepared in good overall yields.
Speciation Analysis of Dissolved Copper in Wastewater with Azocarmine B by Light‐Absorption Ratio Variation Combined with Continuous Flow Analysis
Authors: Wang Hong‐Yan
Published: May 2015

The sensitive complication between Cu(II) and of azocarmine B (ACB) at pH 6.03 was characterized by the spectral correction method and the complex Cu(ACB)2 was formed. Because of a good selectivity, this reaction was used for the determination of Cu(II) by the light‐absorption ratio variation approach combined with the continuous flow analysis (CFA). The limit of detection of Cu(II) is 0.04 mg/L, the recovery is between 97 and 100% and about 30 samples could be analyzed per hour by CFA. By means of the recommended method, the organic species and inorganic ion species of Cu(II) in two wastewater samples were determined respectively and the former occupies less than 20% of total dissolved Cu(II).
Assay of Phenformin Hydrochloride in Pharmaceutics by Coupling with Sodium Nitroprusside
Authors: Wang Min , Zhang Yan , Li Quan‐Min
Published: May 2015

A novel and simple spectrophotometric method for the determination of phenformin hydrochloride using sodium nitroprusside as chromogenic reagent is developed in this paper. The experiment indicates that the sodium nitroprusside can react with the phenformin hydrochloride in a basic solution to form a product with colored N‐nitrosamines. The stoichiometric ratio of phenformin hydrochloride and sodium nitroprusside is 1:3 in the product. The maximal absorption wavelength (λmax) of the product is 520 nm, ϵ520 = 2.2 × 103 Lmol−1cm−1. A Good linear relationship is obtained between the absorbance (A) and the concentration (C) of phenformin hydrochloride in a wide range of 0.20‐400 μg mL−1. The equation of the linear regression is A = 0.03461 + 0.00907C (μg mL−1) with a linear correlation coefficient of 0.9991. The detection limit is 0.13 μg mL−1, and the relative standard deviation (R.S.D.) is 0.19%. The method is successfully applied to the determination of phenformin hydrochloride in tablet forms, and satisfactory recoveries are obtained.
Quantitative Analysis of Nicorandil in Commercial Tablets by Spectrophotometry
Authors: Rahman Nafisur , Ahmad Yasmin , Azmi Syed Najmul Hejaz , Sulaiman Saba A. J.
Published: May 2015

The main aim of this work is to develop and validate a spectrophotometric method for the determination of nicorandil in commercial tablets. The method is based on the reduction of the nitroxy ethyl group of nicorandil into carbonyl compound and nitrite ion by NH4Cl and Zn dust. The nitrite ion thus formed reacts with potassium iodide and starch in dilute HCl medium to form a blue product, which absorbs maximally at 550 nm. Beer's law is obeyed in the concentration range 0.4‐4.0 μg mL−1 with molar absorptivity of 7.92 × 104L mol−1 cm−1. The detection limit is 0.017 μg mL−1. The reaction conditions are optimized and validated as per the International Conference on Harmonisation guidelines (USA). The proposed method has been applied successfully for the determination of nicorandil in commercial tablets. The results of analyses are compared statistically with those of the author's spectrophotometric method, which confirmed that there is no significant difference between the methods compared.
Separation and Retention Behavior of Aromatic Carboxylic Acid Isomers by High‐Performance‐Liquid‐Chromatography Using β‐Cyclodextrin Bonded Phase with Diamine‐s‐Triazine Moiety
Authors: Lin Chen‐Hsing , Chen Chih‐Yu , Chang Shu‐Wen , Wu Jong‐Chang , Liu Yu‐Chih , Lin Ching‐Erh
Published: May 2015

A β‐cyclodextrin (β‐CD) bonded phase with diamine‐s‐triazine moiety was prepared. The separation and retention behavior of the isomers of five aromatic carboxylic acids, including toluic acid, aminobenzoic acid, nitrobenzoic acid, hydroxybenzoic acid, and naphthoic acid were investigated by a high‐performance liquid chromatography (HPLC) using the β‐CD bonded phase prepared. The influence of mobile phase pH in the range of 2.7‐3.6 on the retention of these analytes was examined. The isomers of the aromatic carboxylic acids, with the exception of nitrobenzoic acid, were optimally and effectively separated at pH 2.7, while the three isomers of nitrobenzoic acid could be well separated at pH 3.3. Compared with the chromatographic results obtained previously on the amine‐s‐triazine‐β‐CD bonded phase, the retention factors of the isomers of aromatic carboxylic acid on the diamine‐s‐triazine‐β‐CD bonded phase increase to a relatively much greater extent. Thus, the functionality of the spacer arm of the bonded phase playing an important role in the retention of aromatic carboxylic acid isomers is demonstrated. The results also imply that the hydrogen‐bonding interaction and the mechanism of anion exchange sorption as well may contribute significantly to the retention mechanisms.
Coordination Behavior of a D‐Penicillaminato Aurate(I) Metalloligand Toward Coblat(III) Centers
Authors: Konno Takumi , Toyota Atsushi , Igashira‐Kamiyama Asako
Published: May 2015

Treatment of (NH4)[Au(D‐Hpen‐S)2](D‐H2pen = D‐penicillamine) with CoCl2·6H2O in an acetate buffer solution, followed by air oxidation, gave neutral AuICoIII and anionic AuI3CoIII2 polynuclear complexes, [Au3Co3(D‐pen‐N,O,S)6]([1]) and [Au3Co2(D‐pen‐N,S)6]3− ([2]3−), which were separated by anion‐exchange column chromatography. Complexes [1] and [2]3− each formed a single isomer, and their structures were determined by single‐crystal X‐ray crystallography. In [1], each of three [Au(D‐pen‐S)2]3−metalloligands coordinates to two CoIII ions in a bis‐tridentate‐N,O,S mode to form a cyclic AuI3CoIII3 hexanuclear structure, in which three [Co(D‐pen‐N,O,S)2]− octahedral units and six bridging S atoms adopt trans(O) geometrical and R chiral configurations, respectively. In [2]3−, each of three [Au(D‐pen‐S)2]3− metalloligands coordinates to two CoIII ions in a bis‐bidentate‐N,S mode to form a AuI3CoIII2 pentanuclear structure, in which two [Co(D‐pen‐N,S)3]3− units and six bridging S atoms adopt ∧ and R chiral configurations, respectively.
Aromatization of Hantzsch 1,4‐Dihydropyridines in Solventless System Using Glycinium Chlorochromate
Authors: Hekmatshoar Rahim , Rezaei Akram , Haghighi Masoumeh , Ojghaz Azadeh Jafari , Sajadi Sodeh
Published: May 2015

Glycinium chlorochromate (GCC) supported onto silica gel was used as an effective oxidizing agent for the aromatization of 1,4‐dihydropyridines to corresponding pyridine.
Determination of Cu, Fe, Pb and Zn by Flame‐AAS after Preconcentration Using Sodium Dodecyl Sulfate Coated Alumina Modified with Complexing Agent
Authors: Ghaedi Mehrorang , Niknam Khodabakhsh , Shokrollahi Ardeshir , Niknam Ebrahim
Published: May 2015

A sensitive and simple method for the simultaneous preconcentration of trace transition and heavy metal ions is reported. The method is based on the adsorption of Cu, Fe, Pb and Zn on N,N′‐Diacetyl‐4‐bromo‐2,6‐di(aminomethyl)anisole (DABDAMA) loaded on sodium dodecyl sulfate (SDS) coated alumina. The metal content on the complexes are eluted using 6 mL of 2 mol l−1 nitric acid. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a low RSD. The method has been successfully applied for these metals content evaluation in samples including soil, blood and vegetable samples.
Aspects of Living Radical Polymerization Mediated by Cobalt Porphyrin Complexes
Authors: Peng Chi‐How , Li Shan , Wayland Bradford B.
Published: May 2015

Living radical polymerization (LRP) of methyl acrylate (MA), acrylic acid (AA), and vinyl acetate (VAc) mediated by cobalt(II) porphyrin complexes ((TMP)CoII·, (TMPS)CoII·) are reported. The polymeric products with relatively low polydispersity and controlled number average molecular weight (Mn) based on one polymer chain per cobalt complex demonstrate the living characters of the polymerization process. The formation of block copolymers of poly(methyl acrylate)‐b‐poly(vinyl acetate) (PMA‐b‐PVAc) and poly(methyl acrylate)‐b‐poly(vinyl pyrrolidone) (PMA‐b‐PVP) demonstrate another important feature of LRP and extend the application of cobalt porphyrin mediated radical polymerization to a wider array of functionalized monomers. Kinetic studies using 1H NMR to follow the formation of orGano‐cobalt complexes reveal that two mechanisms, reversible termination (RT) and degenerative transfer (DT), occur during the polymerization process. MA and VAc polymerization mediated by cobalt porphyrin complexes are used to illustrate the properties of these two LRP pathways and evaluate the kinetic and thermodynamic properties for several of the central reactions.
Water‐Dragging Ability of Aromatic Compounds in Octanol‐Water Systems: A Quantitative Approach by Spectra Deconvolution
Authors: Chang Ya‐Ting , Chang Fang‐Yi , Chen Yi‐Kwan , Lee Ching‐Ju , Yang Chung‐Sung
Published: May 2015

This is the first time that the water‐dragging ability of aromatic compounds partitioning in octanolwater biphasic systems is experimentally estimated by a quantitative spectral deconvolution model. The water‐dragging amount, Δ f value, measured by the quantitative model is based on the integrations of peak area increments of component peaks deconvoluted from O‐H modes of water and octanol molecule, recorded by a Fourier‐transformed infrared spectrophotometer. The stoichiometry hydration capacity, Δ fw, is derived from the corresponding Δ f values. Without any tedious experimental procedure or complicated modeling calculation, the Δ fw value is able to give the required solute‐water hydration information. Such an advantage can't be provided by other techniques applied in the field of water‐dragging ability investigation. Six aromatic compounds were used for the method validation. The Δ fw data obtained by this model are generally consistent with literature‐known values. The efficiency of this quantitative spectral deconvolution model can solve the state of aggregations and the structure of hydrates existing in the organic phase. Moreover, this deconvolution model also has the ability to be extended further to investigate the environmental and biological problems related to the organic chemical portioning in the aqueous and non‐aqueous phases.
Design of an Imipramine‐Selective Electrode Based on an Ion‐Pair and its Application to Pharmaceutical Analysis
Authors: Javanbakht Mehran , Safaraliee Leila , Ganjali Mohammad Reza , Abdouss Majid , Norouzi Parviz , Faridbod Farnoush , Fard Solmaz Eynollahi
Published: May 2015

Ion‐selective electrodes play an important role in pharmaceutical analysis due to their simplicity, rapidity and accuracy over some other analytical methods. This research introduces the design of an ion‐pair of imipramine‐tetraphenyl borate (IMP‐TPB) based PVC membrane sensor for IMP hydrochloride determination. Effect of the membrane composition, the pH influence and the effect of lipophilic anionic additives on the response characteristics of the electrode were investigated. After a series of experiments, the best electrode performance was accomplished with a membrane composition of 30% PVC, 63% DBP, 5% (IMP‐TPB) and 2% (NaTPB). This electrode illustrated a fast (15 s), stable and Nernstian response across a relatively wide IMP hydrochloride concentration range (10−5 to 10−5 M), in the pH range of (3.0–8.0), and it can be used for at least two months without any measurable change in sensitivity. Additionally, the interference between IMP and several drugs and common inorganic anions was negligible as shown by the potentiometric selectivity coefficient data. The membrane sensor was successfully applied to the determination of IMP in tablets and human urine samples, and very good recovery results were obtained.
Preparation of Tube‐Like ZrO2/NaCl by Microemulsion Method
Authors: Gao Lin , Song Xiu‐Qin
Published: May 2015

On the basis of w/o microemulsion and surfactant template‐assembly technology, tube‐like ZrO2/NaCl was prepared using sodium bicarbonate as precipitant. The w/o microemulsion consisted of a nonionic surfactant OP emulsifier, cosurfactant pentanol and oil hexamethylene alkyl. The morphology, structure, and optical properties of the tube‐like ZrO2/NaCl have been studied by SEM, XRD, FTIR, UV‐vis, and PL techniques.
Effect of Sulfation of Zirconia on Catalytic Performance in the Dehydration of Aliphatic Alcohols
Authors: Hsu Ya‐Sun , Wang Yin‐Lan , Ko An‐Nan
Published: May 2015

Catalytic dehydration of 2‐propanol and that of 1‐butanol were performed at atmospheric pressure and 150–300°C over ZrO2 and sulfated ZrO2 (S/ZrO2) in a fixed‐bed, tubular reactor. The catalysts were characterized with XRD, elemental analysis, FT‐IR, N2 physisorption, TG/DTA, TPD, and TPR. The main structures of ZrO2 and S/ZrO2 were monoclinic and tetragonal, respectively. As ZrO2 was modified with sulfuric acid, its surface area and acid amount were greatly increased, whereas the pore volume, the pore diameter, and the particle size were reduced. Both samples owned weak basicity. For both reactions, only dehydration products of alkene and ether were obtained. The alcohol conversion enhanced remarkably with the catalyst acid amount and the surface area as well as the reaction temperature. In addition, the ether selectivity on S/ZrO2 decreased with raising the reaction temperature. The activation energy was 81.0 kJ/mol in the propene formation from 2‐propanol over S/ZrO2. The corresponding value was 94.4 kJ/mol for the dehydration of 1‐butanol.
Capillary Electrophoretic Separation of Tricyclic Antidepressants Using 1‐Alkyl‐3‐Methylimidazolium‐Based Ionic Liquids as Background Electrolyte
Authors: Tsai Chia‐Ying , Yang Ching‐Fei , Whang Chen‐Wen
Published: May 2015

A capillary electrophoretic (CE) method coupled with the use of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (1E‐3MI‐TFB) ionic liquid as background electrolyte (BGE) has been developed for the simultaneous separation of nine tricyclic antidepressants, viz. amitriptyline (Ami), clomipramine (Clo), desipramine (Des), fluphenazine (Flu), imipramine (Imi), nortriptyline (Nor), promazine (Pro), thioridazine (Thi) and trimipramine (Tri). Resolution of TCAs with similar molecular structures and pKa values was accomplished by minute manipulation of the electrophoretic velocities of TCAs via reversed electroosmotic flow (EOF) generated by adsorption of 1E‐3MI cations onto the capillary wall. The optimal separation was obtained with a 50 mM 1E‐3MI‐TFB as the sole BGE at pH 3. Symmetric peaks with efficiencies up to 2.4 × 105 plates/m were achieved. RSD values on migration times and peak areas were in the ranges of 0.63–0.95% and 3.41–6.34% (n = 4), respectively. The role of different alkyl groups on the imidazolium cations was also investigated.
Study on the Binding of Chloride Ion to Hemoglobin Using Electromotive Force Method
Authors: Wang Gong‐Ke , Lu Yan , Yan Chang‐Ling
Published: May 2015

The electromotive force of the concentration cell, in which both half‐cells contain the same concentration of sodium chloride, and one of which also contains hemoglobin (Hb), was measured on the isoelectric point of Hb (pH = 6.70). On the basis of Scatchard equation, a stepwise binding model and an improved calculation method were presented. Using the new calculation method, the number of the chloride‐binding sites on Hb molecule and the corresponding binding constants were calculated. The results show that there are three classes of binding groups on a Hb molecule, the number of the binding sites and the corresponding binding constants are n1 = 1, K01 = 245; n2 = 8, K02 = 3.50; n3 = 8, K03 = 1.91, respectively. The factors of influencing the interaction between Cl− and Hb molecule were clarified, and that the differences between our results and the results of computer modeling, as well as the results of molecular dynamics simulation were also discussed.
Mild Oxidation of Oxime Derivatives with KMnO4 in Ionic Liquid Media
Authors: Safaei‐Ghomi Javad , Hajipour Abdol Reza
Published: May 2015

In this research, potassium permanganate in the presence of a catalytic amount of [bmim]Br under solvent free conditions is used as an efficient and chemoselective method for oxidative cleavage of some oximes to corresponding carbonyl compounds. This experiment was carried out in mild conditions without any further oxidation of aldehydes to corresponding acids.
Nucleophilic Solvent Participation in the Solvolysis of Tertiary Bromoalkanes
Authors: Liu Kwang‐Ting , Hou Su‐Jiun , Tsao Meng‐Lin
Published: May 2015

The solvolysis of 2‐bromo‐2‐methylpropane (1B), 2‐bromo‐2‐methylbutane (2B), 2‐bromo‐2, 3‐di‐methylbutane (3B), 2‐bromo‐2, 3, 3‐trimethylbutane (4B), 3‐bromo‐3‐methylpentane (5B), 3‐bromo‐2, 3‐dimethylpentane (6B), 3‐bromo‐2, 2, 3‐trimethylpentane (7B), 3‐bromo‐3‐ethylpentane (8B), 3‐bromo‐3‐ethyl‐2‐methylpentane (9B) and 2‐bromo‐2, 4, 4‐trimethylpentane (11B) in 15 to 21 solvents was studied, and correlation analyses by using the single‐ and dual‐parameter Grunwald‐Winstein equations (Eqns 1 and 2) were examined. Substrates 7B, 9B and 11B showed excellent linear relationship (R ≥ 0.997) in the logk ‐ YBr plots and indicated limiting SN1 mechanism for the solvolysis. On the other hand, bromides 1B‐6B and 8B gave linear correlations (R = 0.987–0.996) with the dual‐parameter (YBr and NOTs) equation (2) only, which indicated the presence of significant nucleophilic solvent participation. Normal trends of reactivity due to the relief of B‐strain could be found in the poorly nucleophilic trifluoroethanol. Similar to the corresponding chlorides, the overwhelming influence of nucleophilic solvent assistance results in the observed inverse order of reactivity: k(2B) > k(3B), k(5B) > k(6B) and k(8B) > k(9B).
A Mild Method for the Protection of Aldehydes as Dithioacetals and Dithiolanes Catalyzed by I2 Generated in Situ Using Fe(NO3)3.9H2O/NaI Under Heterogeneous Conditions
Authors: Rostami Amin , Nik Heidar Ali Alavi , Roosta Zahra Toodeh , Khazaei Ardeshir
Published: May 2015

Structurally diverse aromatic aldehydes were thioacetalated in a clean and efficient reaction with ethane‐1, 2‐dithiol and thiophenol based on the use of I2 generated in situ from Fe(NO3)3.9H2O/NaI. The reaction occurs in good to high yield in dichloromethane at room temperature and the use of toxic and corrosive molecular iodine is avoided.
Computational Study on the Unconventional Hydrogen‐Bonded F–H···C Systems
Authors: Liao Hsin‐Yi
Published: May 2015

The F–H···YZ2 (Y = C, Si, BH, A1H;Z = H, PH3) systems were examined using density functional theory calculations. The main focus of this work is to demonstrate that the chemistry of Y(PH3)2 exhibits a novel feature which is a central Y atom with unexpected high basicity. Further, the hydrogen bond strength can be adjusted by the substitution of H atoms of YH2 by PH3 groups. The FH···C(PH3)2 system has the strongest hydrogen bond interaction, which is larger than a conventional hydrogen bond. In addition to electrostatic interaction, donor‐acceptor interaction also plays an important role in determining the hydrogen bond strength. Therefore, a carbon atom can not only be the hydrogen bond acceptor but also can create an unusual stabilized hydrogen bond complex. Also, X3B–YZ2 (X = H, F; Y = C, Si, BH, A1H;Z = PH3, NH3) systems were examined, and it was found that the bond strength is controlled predominately by the HOMO‐LUMO gap (ΔIP). The smaller the ΔIP, the larger the bond dissociation energy of the B–Y bond. In addition, NH3 is a better electron‐donating group than PH3, and thus forms the strongest donor‐acceptor interaction between X3B and Y(NH3)2.
XANES Spectroscopic Studies of the Phase Transition in Gd2Zr2O7
Authors: Lee Yu‐Hsuen , Chen Jin‐Ming , Lee Jyh‐Fu , Kao Huey‐Chuen I.
Published: May 2015

The structural phase transition from fluorite to pyrochlore and the strength of the coordination bond of Zr–O in Gd2Zr2O7 were investigated by XANES spectra of both O and Zr K‐edge. The energy difference of the O K‐edge absorption spectra at 532 and 536 eV was assigned to the crystal field splitting energy of the 4d orbital (ΔE4d, t2g and eg) of the Zr ion. Also, in the samples prepared at higher temperatures, the 536 eV peak moves slightly to higher energy, whereas the absorption energy of 532 eV peak does not shift. A correlation between ΔE4d and the strength of interaction between Zr (4d) and O (2p) orbitals has been found. Furthermore, two Zr K‐edge absorptions at 18020 and 18030 eV of Gd2Zr2O7 have been observed; the splitting energy (ΔE), peak intensity ratio (I18030/I18020), and FWHM of the first derivative of the absorption curve depend on the preparation temperatures. The effect of crystal symmetry and Zr‐O bonding character on the XANES spectral profile was discussed.
Determination of Silver by Flame Atomic Absorption Spectrometry after Preconcentration on Naphthalene Modified with Dithizone
Authors: Fathi M. R. , Pourreza N. , Purweis S.
Published: May 2015

A solid‐phase extraction method for preconcentration of silver and consequent determination by atomic absorption spectrometry is described. The method is based on the adsorption of silver on naphthalene modified with dithizone in a column. The adsorbed silver is eluted from the column with a thiourea solution and determined by flame atomic absorption spectrometry. The adsorption conditions including pH, reagent concentration, eluent volume, flow rate and interfering ions were investigated. The calibration graph was linear in the range 10–1000 ng mL−1 of Ag in the initial solution with r = 0.9998. The limit of detection based on 3Sb was 3.9 ng mL−1. The relative standard deviation for ten replicate measurements of 40 and 600 ng mL−1 of Ag was 4.4% and 0.9%, respectively. The method was applied to the determination of silver in mineral, radiology film and wound dressing samples.
On‐Line Selective Solid‐Phase Extraction of Copper with a Surface Ion Imprinted Silica Gel Sorbent
Authors: Guo Jia‐Jia , Su Qing‐De , Gan Wu‐Er
Published: May 2015

Copper(II)‐ion imprinted silica gel (Cu‐IISG) sorbent was synthesized by surface imprinting technique and was employed as a selective solid‐phase extraction material for on‐line preconcentration and separation, then coupled with atomic absorption spectrometry (AAS) determination of Cu(II). The higher selectivity coefficient of Cu‐IISG for Cu(II) in the presence of competitive ions such as Fe(III), Ni(II) and Zn(II) was above 411, which was 35 times of NISG. The static adsorption capacity and dynamic adsorption capacity were 41.11 mg g−1 and 16.20 mg g−1, respectively. The Cu‐IISG offered a fast kinetics for the adsorption and desorption of Cu(II), which can be used for on‐line preconcentration and detection. Two certified reference materials of GBW07301a sediment and GBW07401 soil were analyzed and the determined values were in a good agreement with the certified values. The developed method was also successfully applied to the determination of trace copper in tea leaf with satisfactory results (recovery between 96.3% and 102.3%).
One‐Step Electrodeposited Carbon Nanotube/Zirconia/Myoglobin Film for Direct Electron Transfer and Electrocatalysis
Authors: Qu Song , Pei Su‐Peng , Zhou Shi‐Lin , Gu Ying‐Ying
Published: May 2015

A nanobiocomposite film consisted of zirconia, multiwalled carbon nanotubes (MWNTs) and Myoglobin (Mb) was electrochemically deposited on the electrode. Direct electron transfer for the immobilized Mb was realized and high electrocatalytic efficiency toward H2O2 was observed. The proposed biosensor via a simple one‐step electrodeposition method displayed a broader linear range and a lower detection limit for H2O2, as compared with those CNT or ZrO2 based biosensor. The linear range is from 2 × 10−6 M to 1 × 10−3 M with the detection limit of 6 × 10−7 M. The present strategy provides a simple and effective method to assemble CNT, ZrO2 and enzyme nanohybrid on the electrode and expands the scope of CNT‐based electrochemical devices.
Classifying Human Haptoglobin Phenotypes on Native‐PAGE Using a Modified Coomassie Brilliant Blue R 250 Staining
Authors: Liau Chun‐Yi , Ueng Kwo‐Chang , Lin Chung‐Sheng
Published: May 2015

There are three types of human Haptoglobin, Hp 1‐1, Hp 2‐1, and Hp 2‐2, each characterized by a distinct combination of the two α chains of the holoprotein. A modified Coomassie Brilliant Blue R 250 (mCBB‐R250) staining method for detecting the phenotypes of human blood haptoglobin molecules is presented. Addition of excess hemoglobin to the sample allowed specific formation of different haptoglobin‐hemoglobin complexes, which, in turn can be separated into distinctive migration pattern on native‐PAGE and stained by CBB‐R250. The typing results are consistent with that using Western blotting. In comparison to the existing methods for haptoglobin typing, our method is comparable in accuracy, and is easier to carry out. The results on typing of 29 plasma samples from Taipei Blood Center were also presented.
Application of Cloud Point Extraction for Copper, Nickel, Zinc and Iron Ions in Environmental Samples
Authors: Ghaedi Mehrorang , Niknam Khodabakhsh , Niknam Ebrahim , Soylak Mustafa
Published: May 2015

A cloud point extraction procedure was presented for the preconcentration of copper, nickel, zinc and iron ions in various samples. After complexation by 2‐(6‐(1H‐benzo[d]imidazol‐2‐yl)pyridin‐2‐yl)‐1H‐benzo[d]Imidazole (BIYPYBI), analyte ions are quantitatively extracted in Triton X‐114 following centrifugation. 1.0 mol L−1 HNO3 nitric acid in methanol was added to the surfactant‐rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for BIYPYBI, Triton X‐114 and HNO3 and bath temperature, centrifuge rate and time were optimized. Detection limits for Cu2+, Fe3+, Zn2+ and Ni2+ ions was 1.4, 2.2, 1.0 and 1.9 ng mL−1, respectively. The preconcentration factors for all ions was 30, while the enrichment factor of Cu2+, Fe3+, Zn2+ and Ni2+ ions was 35, 25, 39 and 30, respectively. The proposed procedure was applied to the analysis of real samples.
Polar Constituents from Sageretia Thea Leaf Characterized by HPLC‐SPE‐NMR Assisted Approaches
Authors: Shen Ca‐Jane , Chen Chien‐Kuang , Lee Shoei‐Sheng
Published: May 2015

Nine glycosides (1–9) were characterized from the n‐butanol‐soluble fraction of the ethanolic extract of the leaves of Sageretia thea by the general approach. Among these, Compounds 6 and 7 were identified as a mixture. Application of HPLC‐SPE‐NMR in two selected fractions led to the separation of this mixture and the characterization of three additional minors (10–12). Among these, 7‐O‐methylmyricetin 3‐O‐α‐l‐arabinofuranoside (8) is a new natural product and eight compounds, i.e. glucofragulin A (1), quercetin‐3‐O‐α‐l‐arabinopyranoside (5), 3‐O‐β‐d‐galactopyranoside (6), 3‐O‐β‐d‐glucopyranoside (7), and 3‐O‐α‐l‐arabinofuranoside (11), myricetin‐3‐O‐α‐l‐arabinofuranoside (9) and 3‐O‐β‐d‐glucopyranoside (10), and quercetrin (12), are found for the first time from the title plant.
Synthesis of Glucosylguanidinohydrazones under Microwave Promotion and Ultrasound Irradiation
Authors: Chen Hong‐Mei , Cao Ling‐Hua
Published: May 2015

Guanylhydrazone derivatives were obtained by the condensation of glucosylated aminoguanidines with 3‐formylchromones in refluxing THF. Target compounds were synthesized by conventional method, microwave promotion and ultrasound irradiation methods. The structure of all new compounds was confirmed by IR, 1H NMR, 13C NMR spectral data and elemental analyses.
Reusable and Efficient Cul/TBAB‐Catalyzed Iodination of Terminal Alkynes in Water under Air
Authors: Chen Shao‐Nung , Hung Tzu‐Ting , Lin Tze‐Chiao , Tsai Fu‐Yu
Published: May 2015

An environmentally‐friendly and operationally‐simple process for the synthesis of 1‐iodoalk‐1‐ynes under mild conditions catalyzed by CuI/TBAB in water under air was developed in this study. Catalyst loadings of CuI as low as 1–2 mol% gave 1‐iodoalk‐1‐ynes in good to high yields, and the residual aqueous solution after extraction with hexane could be reused for the next reaction without any treatment.
Photocatalytic Degradation of Ethyl tert‐Butyl Ether in Aqueous Solution Mediated by TiO2 Suspensions: Parameter and Reaction Pathway Investigations
Authors: Lu Chung‐Shin , Chiang Tien‐Yu
Published: May 2015

Degradation of ethyl tert‐butyl ether (ETBE) with UV/TiO2 was studied by solid‐phase microextraction and gas chromatography‐mass spectrometry. The complete removal of 0.1 g L−1 of ETBE was achieved after 20 h of treatment. Factors such as pH of the system, catalyst and substrate concentration, and the presence of anions influenced the degradation rate. Establishment of the degradation pathway was made possible by a thorough analysis of the reaction mixture, which identified the main intermediate products generated. The possible degradation pathways were proposed and discussed in this research. The attack on the C–H bond in ETBE by ·OH forms an alkyl radical, which consequently produces a peroxyl radical upon reaction with oxygen. Peroxyl radicals react with one another and produce an alkoxy radical. The β‐bond fragmentation of the alkoxy radical produces different intermediates.