bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoinduced Electron Transfer Research to Build Model Compounds of Artificial Photosynthesis and Solar Energy Conversion
Authors: Ganguly T. , Pal S. K.
Published: May 2015

In this article various novel synthesized dyads and triad systems containing organic based electron donor and acceptor compounds linked together by flexible and rigid spacers have been described which undergo very fast (˜ ps) charge separation reactions and relatively slow energy destructive charge recombination. Various techniques have been discussed to enhance the survival duration of the charge‐separated products, resulted from photoinduced electron transfer reactions, by retarding the energy wasting charge recombination process. It has been hinted that these systems should form the basis of future artificial photosynthetic and solar energy conversion devices.
Room Temperature Ionic Liquids as Media for Photophysical Studies
Authors: Mandal Prasun K. , Paul Aniruddha , Samanta Anunay
Published: May 2015

In this article, we first present a brief introduction on room temperature ionic liquids based on substituted imidazolium salts that have been the focus of extensive studies in recent years. Subsequently, we summarize some of the photophysical studies made in these ionic liquids. Finally, we discuss the suitability of the imidazolium ionic liquids in optical studies taking into consideration their absorption and fluorescence behavior.
A New Approach of Flow Graph Theory Applied in Physical Chemistry
Authors: Socol Marius , Baldea Ioan
Published: May 2015

An alternative method for solving homogenous and non‐homogenous differential equation systems used in chemical kinetics and pharmacokinetics on the basis of flow graph principles has been proposed. The classical method of solving these systems with flow graphs involves the employment of Laplace transform before depicting a flow graph and the inverse Laplace transform after using Mason's rules. A short description of flow graph algebra has been presented. One model very often encountered in pharmacokinetics was solved by both flow graph methods in order to make a comparison. Our proposed method is simpler and more direct, eliminating the Laplace transforms. The calculus is made directly on the base of the flow graph representing the image of reaction scheme (pharmacokinetic model).
Cyclohexene Hydroconversion Using Monometallic and Bimetallic Catalysts Supported on γ‐Alumina
Authors: Aboul‐Gheit Ahmed K. , Abdel‐Hamid Sohair M. , Aboul‐Fotouh Sameh M. , Aboul‐Gheit Noha A. K.
Published: May 2015

The hydroconversion of cyclohexene (CHE) using monometallic catalysts containing 0.35wt% of Pt, Pd, Ir or Re on a γ‐alumina support, as well as bimetallic catalysts containing combinations of 0.35wt% Pt with 0.35wt% of either Pd, Ir or Re on γ‐alumina, were investigated in a plug flow‐type fixed‐bed reactor. The Cyclohexene (CHE) feed was injected continuously with a rate of 8.33 × 10−3mole h−1 on 0.2 g of catalyst using a simultaneous hydrogen gas flow of 20 cm3 min−1 throughout a broad reaction temperature range of 50–400 °C. The dispersion of the metals in the catalysts was determined via H2 or CO chemisorption. The activities of the monometallic catalysts were found to be in the order: Pd > Pt > Ir > Re, whereas those of the bimetallic catalysts were in the order: PtPd > PtIr > PtRe.

Cyclohexene hydrogenation and dehydrogenation reactions using the current mono‐ and bimetallic catalysts were kinetically investigated applying the absolute reaction rate theory, whereby reaction rate constant, activation energy, enthalpy and entropy of activation were computed to explain surface variations on these catalysts.
The Adsorption, Thermal Desorption and Photochemistry of Methyl Iodide on an Ag‐Covered TiO2(110) Surface
Authors: Su Chaochin , Chen Chih‐Chieng , Tsai Chih‐Song , Lin Jong‐Liang , Lin Jiing‐Chyuan
Published: May 2015

The thermal reactions and photochemistry of monolayer methyl iodide (CH3I) on a silver covered TiO2(110) surface have been studied using combinative techniques of temperature programmed desorption (TPD) and x‐ray photoelectron spectroscopy (XPS). About ˜ 60% of CH3I at monolayer coverage on Ag/TiO2(110) dissociates between 130 and 200 K yield adsorbed CH3 and I, with the rest desorbing molecularly at a peak temperature of 200 K in a TPD study. Photochemistry of CH3I on Ag/TiO2(110) is wavelength dependent. Irradiation of monolayer CH3I by 404 nm photon causes C‐I bond dissociation and CH3 desorption. Upon 290 nm, UV irradiation, the depletion of CH3I(a) is dominated by photodesorption of molecular CH3I.
Intermolecular Se···I Interactions Identified in Cu11(μ9‐Se)(μ3‐I)3[Se2P(OEt)2]6 Form a One Dimensional Polymeric Chain
Authors: Hunga Chiu‐Mine , Chu Yi‐Hua , Santra Bidyut K. , Liaw Ben‐Jie , Wang Ju‐Chun , Liu C. W.
Published: May 2015

The undecanuclear copper cluster Cu11(μ9‐Se)(μ3‐I)3[Se2P(OEt)2]6 1, has been isolated along with Cu8(μ8‐Se)[Se2P(OEt)2]6 2, from the reaction of NH4Se2P(OEt)2, Cu(CH3CN)4PF6, and Bu4NI in a molar ratio of 3:2:2 in diethyl ether. The molecular formulation of 1 was confirmed by elemental analysis, positive FAB mass spectrometry, multinuclear NMR (1H, 31P, and 77Se), and X‐ray diffraction. In cluster 1 eleven copper atoms adopt the geometry of a 3,3,4,4,4‐pentacapped trigonal prism with a selenium atom in the center. The coordination geometry for the central, nonacoordinated selenium atom is tricapped trigonal prismatic. In addition, the central core Cu11Se is further stabilized by three iodides and six dsep ligands. Besides, weak inter‐molecular Se···I interactions (3.949–3.972 Å) are uncovered and form a one dimensional polymeric chain.
Total Solubility Determination of Mixtures Containing Ampicillin Anhydrate and Ampicillin Trihydrate
Authors: Liu Chen‐Lun , Chang Tian‐Chan , Wu Shu‐Min , Chiang Huey‐Jenn
Published: May 2015

The dissolved concentrations of ampicillin anhydrate, ampicillin trihydrate, and their mixtures were experimentally determined. For 100% ampicillin anhydrate and 100% ampicillin trihydrate cases, the dissolved concentration (mg/mL) was equal to the total amount of 100% ampicillin anhydrate and 100% ampicillin trihydrate in 1 mL solution up to the solubility (10.8 mg/mL) of 100% ampicillin anhydrate and the solubility (5.4 mg/mL) of 100% ampicillin trihydrate. For an ampicillin anhydrate to ampicillin trihydrate mixture ratio of 75:25, the relationship between the dissolved concentration and the total amount of the mixture in 1 mL solution was the same as the 100% ampicillin anhydrate case. As for the ampicillin anhydrate to ampicillin trihydrate mixture ratios of 50:50 and 25:75, the total solubility of 10.8 mg/mL could be reached at greater amounts of the mixtures. A model of diffusion‐controlled dissolution rate mechanism with two experimental solubilities, 10.8 mg/mL for ampicillin anhydrate and 5.4 mg/mL for ampicillin trihydrate, was used to successfully interpret the solubility data.
Flow Injection Analysis of Ascorbyl Glucoside in Cosmetics by a Disposable Printed‐Circuit Board Waste Modified Electrode
Authors: Shih Ying , Zen Jyh‐Myng
Published: May 2015

Ascorbyl glucoside, i.e., ascorbic acid 2‐glucoside (AA‐2G), is anew type of stable vitamin C derived compound used in many cosmetic skin‐lightening formulations, but rarely studied in the literature. In this study, a screen printed electrode modified with copper‐enriched printed circuit‐board waste (designated as CuPCB/SPE) was applied to study the electrochemical characteristics of AA‐2G. Cyclic voltammogram of the CuPCB/SPE showed an electrocatalytic oxidative feature at ˜0.6 V vs. Ag/AgCl in 0.15 M NaOH solution. Flow injection analysis coupled with the CuPCB/SPE was further developed for sensitive AA‐2G determination. The calibration plot was linear in the window of 2.5–160 ppm with slope and regression coefficient of 0.0169 μA/ppm and 0.9971, respectively. The detection limit (S/N = 3) was 0.247 ppm. Real sample analysis was demonstrated for different skin‐lightening cosmetic products with appreciable results.
Synthesis of 2‐Phenylthiazoles from α‐Tosyloxyketones and Thiobenzamide in [Bmim][PF6] Ionic Liquid at Ambient Temperature
Authors: Hou Rei‐Sheu , Wanga Huey‐Min , Tsai Hsing‐Hui , Chen Ling‐Ching
Published: May 2015

The room temperature ionic liquid, 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate [bmim][PF6] is used as a ‘green’ recyclable alternative to classical molecular solvents for the cyclocondensation of α‐tosyloxyketones with thiobenzamide to prepare 2‐phenylthiazoles in good yields.
High Resolution NMR Spectroscopic Study of Complexation of Hydroxyzine Hydrochloride with β‐Cyclodextrin in Aqueous Solution
Authors: Ali Syed Mashhood , Maheshwari Arti , Upadhyay Santosh Kumar , Nam Kye Chun
Published: May 2015

Hydroxyzine hydrochloride forms two 1:1 inclusion complexes with β‐cyclodextrin in aqueous solution as confirmed by the 1H NMR titration and ROESY studies. One complex is formed by the deep penetration of the chlorophenyl ring from the wider rim side, while the mode of entry of the phenyl ring into the β‐CD cavity is not clear. The stoichiometry and overall association constant of the complexes have been determined by the treatment of 1H NMR shift data. Some chiral discrimination by the host between the two enantiomers of hydroxyzine hydrochloride is also indicated.
Synthesis and Reactions of Some New Pyrrolylfuro[2,3‐d]Pyrimidines and Pyrrolopyrazinofuropyrimidines
Authors: Abdel‐Mohsen SH. A. , Abdel‐Hafez SH. H. , Geies A. A.
Published: May 2015

5‐Amino‐4‐methyl‐2‐phenyl‐6‐substitutedfuro[2,3‐d]pyrimidines (2a‐c) were reacted with 2,5‐dimethoxytetrahydrfuran to afford the pyrrolyl derivatives 3a‐c. Compound 3a was chosen as intermediate for the synthesis of poly fused heterocycles incorporated furopyrimidines moiety 4–11. Some of the synthesized compounds were screened for their antibacterial and antifungal activities.
Volumetric Properties for the Electrolyte (NaCl, NaBr and NaI) Monosaccharide (D‐Mannose and D‐Ribose)‐Water Systems at 298.15 K
Authors: Zhuo Ke‐Lei , Zhao Yang , Yang Li‐Xia , Liu Qian , Wang Jian‐Ji
Published: May 2015

Densities have been measured for the electrolyte (NaCl, NaBr and NaI)‐monosaccharide (D‐mannose and D‐ribose)‐water solutions at 298.15 K. These data have been used to calculate the apparent molar volumes of the saccharides (VΦ,S) and electrolytes (VΦ,E) in the studied solutions. Infinite dilution apparent molar volumes, VΦ,S0 and VΦ,E0, have been evaluated, together with the standard transfer volumes of the saccharides (ΔtVS0) from water to aqueous electrolyte solutions and those of the electrolytes (ΔtVE0) from water to aqueous saccharide solutions. It was shown that both the ΔtVS0 and ΔtVE0 values are positive and increase with increasing molalities of sodium halides and saccharides, respectively. Overall, the ΔtVS0 and ΔtVE0 values have the order of NaCl > NaBr > NaI except for NaI‐ribose and NaI‐ribose. Volumetric interaction parameters for the electrolyte‐monosaccharide pairs in water were obtained and interpreted by the stereochemistry of the monosaccharide molecules and the structural interaction model.
Studies on the Spectral Behavior between Protein with Poniacyl Carmine 2B and its Analytical Application
Authors: Wei Qin , Li Yan , Duan Cai‐Hong , Ma Hong‐Min , Du Bin
Published: May 2015

In this paper, the spectral behavior of protein and Poniacyl Carmine 2B (PC 2B) has been studied by spectrophotometric method. The conditional constants, apparent combination constant K and maximum binding number n, were used to express the combination ability of the reactions between PC 2B and protein under a set of given conditions. The Sandell index s was used to express the sensitivity of the determination of protein. The factors, acidity, PC 2B concentration and the ionic strength, were discussed by the change of apparent combination constant and maximum binding number. It was found that acidity of the solution, PC 2B concentration and ionic strength had a significant effect on the sensitivity of the assay of protein. Under the optimal conditions, the apparent combination constant K and the maximum binding number n were 2.36 × 106 L mol−1 and 95, respectively. With further investigation, it was found that the Scatchard model was suitable in treating the data obtained in the experiments. In the buffer medium of HCl‐KCl at 1.87, the addition of protein made the maximum absorption of the system move from 527 nm to 513 nm. Its apparent molar absorptivity is 4.46 × 105 Lmol−1 cm−1 at 513 nm. Beer's law is obeyed in the range of 0 ˜ 55 μg mL−1. The system developed in this paper has been used for the determination of protein in milk powder successfully.
A Convenient Oxidation of 5‐Substituted Pyrazol‐3(2H)‐Ones Into Methyl 2‐Alkynoates Using Poly[4‐(Diacetoxyiodo)Styrene]
Authors: Huang Zhen‐Zhong , Sheng Shou‐Ri , Liu Xiao‐Ling , Lin Shu‐Ying , Huang Ren‐Sheng
Published: May 2015

An operationally simple oxidation of 5‐substituted pyrazol‐3(2H)‐ones to the corresponding methyl‐2‐alkynoates in good yields with a mediated poly[4‐(diacetoxyiodo)styrene] system in methanol and acetonitrile at room temperature was carried out. The polymeric reagent can be regenerated and reused as an environmentally benign reagent.
Supramolecular Assembly of Triangulo Pd(II) Diimine Complexes Containing Triply‐Bridging Sulfide Ligands
Authors: Tzeng Biing‐Chiau , Wu Ya‐Ling , Kuo Jau‐Huei
Published: May 2015

We report here a substituent effect of diimines on the solid‐state assembly of interesting triangulo Pd(II) complexes, [(Pd(d‐t‐bpy))3(μJ3‐S)2][NO3]2 1·[NO3]2 and [(Pd(bpy))3(μ3‐S)2][ClO4]2 2·[ClO4]2 (d‐t‐bpy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine, bpy = 2,2′‐bipyridine). 2·[ClO4]2 shows the intermolecular π···π interactions leading to the formation of one‐dimensional frameworks, whereas 1·[NO3]2 only shows the discrete structure in the solid state, featuring an interesting herring‐bone arrangement. The variation in structural motifs from 1·[NO3]2 to 2·[ClO4]2 is expected to be dominated by the substituent's steric hindrance for the diimine ligand. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to a substituent's modification of the diimine ligand.
Preparation and Characterization of a Cobalt‐Containing Mono‐Phosphine Ligand and its Coordinated Molybdenum Complex
Authors: Huang Yi‐Luen , Wang Min‐Ging , Hong Fung‐E
Published: May 2015

A cobalt‐containing monodentate phosphine [(μ2‐PPh2CH2PPh2‐κ2P)Co2(CO)4][μ2‐η2‐PhC≡CP(i‐Pr)2] 2f, was prepared from the reaction of (μ2‐PPh2CH2PPh2‐κ2P)Co2(CO)6 1 with PhC≡CP(i‐Pr)2. It was accompanied by an oxidized compound, [(μ2‐PPh2CH2PPh2‐κ2P)Co2(CO)4][μ2‐η2‐PhC≡CP(=O)(i‐Pr2)] 2fo during the chromatographic process. Further reaction of 2f with Mo(CO)6 resulted in the formation of a 2f‐ligated molybdenum complex 4, [(μ2‐PPh2CH2PPh2‐κ2P)Co2(CO)4][μ2‐η2‐PhC≡CP(i‐Pr2)‐κP]‐Mo(CO)5.
Sorption Studies of Nickel ions Onto Sawdust of Dalbergia Sissoo
Authors: Habib‐ur‐Rehman  , Shakirullah Mohammad , Ahmad Imtiaz , Shah Sher , Hameedullah
Published: May 2015

Sawdust of Dalbergia sissoo, a byproduct of sawmills, was found to be a promising adsorbent for the removal of nickel ions from aqueous solution. Sorption of nickel ions onto sawdust of Dalbergia sissoo was studied using the batch technique. Kinetics studies show that nickel ions sorption process obeys a first order rate law. The applicability of the Langmuir and Freundlich models for the data was tested. Both the models adequately describe the experimental data of the biosorption of nickel ions. The sorption capacities and energies were calculated. Langmuir parameters Xm and K1 were found to increase with rise in temperature; Freundlich constants 1/n and Kf have been evaluated for 293K, 303K, 313K and 323K. Thermodynamic parameter ΔH° = 4.80 kJ mol−;1 shows that sorption of nickel ions onto sawdust is an endothermic process.
A Coated Graphite Thorium‐Ion Selective Potentiometric Sensor Based on a Calix[4]arene Bearing Phosphoryl Groups
Authors: Hassanzadeh P. , Yaftian M. R. , Bahari Z. , Matt D.
Published: May 2015

5,11,17,23‐Tetra‐tert‐butyl‐25,26,27,28‐tetrakis(diphenylphosphinoylmethoxy)calix[4]arene (1)has been used for the preparation of a graphite coated thorium ion‐selective electrode (Th4+‐ISE). The plasticized PVC membrane containing 30% PVC, 58% ortho‐nitrophenyloctylether (NPOE), 4% sodium tetraphenylborate (NaTPB) and 8% ionophore was directly coated on a graphite rod. This sensor gave good Nernstian responses with a slope of 15.5 ± 0.1 mV/decade over a concentration range of 1 × 10−5 −1 × 10−3 M of thorium ions with a limit of detection of 7.9 × 10−6 M. The dynamic response time of the electrode to achieve a steady potential was found to be about 15 seconds. The potential of the prepared sensor was independent of the pH variation in the range 2.3–4.0. The selectivity relative to several mono‐, di‐ and tri‐valent metal ions, i.e. Li+, Na+, K+, Ag+, NH4+, Sr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, La3+, Sm3+, Dy3+, Er3+ and Y3+ was examined. This electrode can be used for 6 months without any considerable divergences in the potential response. The sensor was successfully used as an indicator electrode for the potentiometric titration of a thorium solution using a standard solution of EDTA.
Voltammetric Studies on Chromotrope 2B‐Protein Interaction and Its Analytical Application
Authors: Sun Wei , Jiao Kui , Han Jun‐Ying , Xu Gui‐Yun
Published: May 2015

In this paper the interaction of chromotrope 2B (Ch2B) with proteins was studied by the electrochemical method. Ch2B is an azo dye and shows irreversible electrochemical responses on the mercury electrode in a pH 3.0 Britton‐Robinson (B‐R) buffer solution. After the addition of human serum albumin (HSA) into the Ch2B solution, an interaction took place, and a supramolecular complex was formed in the mixed solution. The electrochemical parameters of the Ch2B‐HSA interaction system were calculated and compared. The results showed that in the absence and presence of HSA in Ch2B solution, the electrochemical parameters such as the formal potential E0, the electrode reaction standard rate constant ks, etc. showed no significant changes, which indicated that an electro‐inactive supramolecular biocomplex was formed. The free concentration of Ch2B in reaction solution was decreased, and this resulted in the decrease of the peak current. The binding constant and the binding ratio were calculated as 7.85 × 109 and 1:2, respectively, and the interaction mechanism was discussed. Based on the decrease of the peak current, this new electrochemical method was proposed for the determination of HSA in the concentration range of 2.0˜25.0 mg/L with the linear regression equation as ΔIp′ (nA) = 50.56C (mg/L) — 6.72 (γ = 0.995). This method was further used to determine other different kinds of proteins, such as bovine serum albumin (BSA), oval albumin, etc‥ The new method was successfully applied to detect the content of albumin in healthy human serum samples with the results in good agreement with the traditional Coomassie Brilliant Blue G‐250 spectrophotometric method.
Synthetic Approaches to Some Polymethine Asycyanine Colorants; Impact of Functional Additives & Chain Elongation on Visible Electronic Spectra
Authors: Ansari Abdus Samad , Narayan Bhupender , Kunwar Ganesh Kr.
Published: May 2015

Twenty one new chromophoric chain β‐substituted polymethine asycyanine (CCBSPA) colorants have been synthesised by catalytic condensation of (i) 4‐dimethylaminophenylbutadientylphenyl ketone; (ii) 4‐dimethylbutadienyl‐4‐nitrophenyl ketone; and (iii) 4‐dimethylaminophenylbutadienyl‐4‐methyl‐phenyl ketone with 2‐methyl quinoline methiodide and 2‐methyl‐6‐substituted quinoline methiodides using piperidine as catalyst & ethanolic DMF as solvent.

These colorants were synthesized with the object to study the impact of various functional groups and chain lengthening on visible electronic spectra. All the colorants showed increase in electronic spectra whether electron withdrawing or donating. These colorants also absorb at higher wavelengths when compared to the previously reported butadienylene chain asycyanino‐colorants.
Trichodiene Synthase: Synthesis and Inhibition Kinetics of 12‐Fluoro‐farnesylphosphonophosphate for Sesquiterpene Cyclases
Authors: Chen Yi‐Lin , Chiu Hsien‐Tai
Published: May 2015

trans, trans‐Farnesyl diphosphate (FPP) serves as a universal substrate for a large family of sesquiterpene cyclases that are responsible for biosynthesis of more than 300 structurally diverse sesquiterpenes in nature. A new FPP substrate analogue, 12‐fluoro‐farnesylphosphonophosphate (12‐F‐F‐CH2PP), was synthesized in this paper for applications on kinetic and mechanistic studies of the enzyme family. Trichodiene synthase (TS), a sesquiterpene cyclase, catalyzes the conversion of trans, trans‐farnesyl diphosphate (FPP) to trichodiene. 12‐F‐F‐CH2PP was tested as a potential inhibitor of TS. Inactivation and inhibition kinetic experiments showed that 12‐F‐F‐CH2PP was not a mechanism‐based inactivator for TS; instead, a mixed‐type reversible inhibition was observed with inhibition constants Ki1 = 2.33 ± 0.50 μM and Ki2 = 25.80 ± 7.70 μM, values close to those previously determined for farnesylphosphonophosphate, Ki1 = 3.25 μM and Ki2 = 9.10 μM. Although 12‐F‐F‐CH2PP did not irreversibly inactivate TS, this new analogue serves as a potential active‐site directed inactivator and mechanistic probe of other sesquiterpene cyclases and FPP‐utilizing enzymes, which utilize FPP as a common acyclic substrate.
Synthesis and Molecular Recognition of Molecularly Imprinted Polymer with Ibuprofen as Template
Authors: Hung Chin‐Yin , Huang Yun‐Tzu , Huang Han‐Hung , Hwang Ching‐Chiang
Published: May 2015

Ibuprofen and ketoprofen are chemically similar non‐steroidal anti‐inflammatory drugs widely used in the treatment of arthritis. Using a molecular imprinting technique, a simple and rapid method was developed for the simultaneous separation and determination of ibuprofen and ketoprofen. Molecular imprinting introduces artificial binding sites into a synthetic polymer matrix, allowing it to exhibit selective rebinding of template molecules. Imprinted polymers can be regarded as an HPLC stationary phase, important for pharmaceutical analysis.

Most molecularly imprinted polymers (MIPs) are synthesized by free radical polymerization of functional monomers, resulting in an excess of crosslinking monomers. In this study, MIPs have been prepared with a ibuprofen template, which can form intramolecular hydrogen bonds. Methacrylic acid (MAA) and ethyleneglycol dimethacrylate (EGDMA) were used as the functional monomer and cross‐linker, respectively. Bulk polymerization was carried out at 4 °C under UV radiation. The resulting MIP was ground into 25˜44 μm particles, which were slurry‐packed into analytical columns. Template molecules were removed by methanol‐acetic acid (9:1, v/v). We evaluated the template binding performance of the MIP using HPLC, with ultraviolet (UV) detection at 234 nm. Chromatographic resolution of ibuprofen and ketoprofen on the MIPs were appraised using buffer/acetonitrile (45/55, v/v) as the mobile phase. Results show that the MIPs prepared using ibuprofen as the template had a significant molecular imprinting effect. The method was successfully applied to the separation and analysis of ibuprofen and ketoprofen in pharmaceuticals.
Synthesis of 1,3,4‐Oxadiazoles and 1,3‐Thiazolidinones Containing 1,4,5,6‐Tetrahydro‐6‐pyridazinone
Authors: Tao Jing , Cao Ling‐Hua , Wang Cai‐Fang , Wang Duo‐Zhi
Published: May 2015

The reaction of 1,4,5,6‐tetrahydro‐6‐pyridazinone‐3‐carboxylic acid hydrazides (1) with aromatic aldehydes afforded 1,4,5,6‐tetrahydro‐6‐pyridazinone‐3‐carbonyl aromatic aldehyde hydrazones (2a‐2g). Heterocyclic derivatives linked 1,3,4‐oxadiazole obtained by cyclocondensation of 2a‐2g with acetic anhydride in absolute ethanol, and 2a‐2g cyclized with mercaptoacetic acid in DMF in the presence of anhydrous ZnCl2 afforded the 1,3‐thiazolidinone derivatives. The structures of the new compounds were established by elemental analyses, IR, 1H NMR and MS spectral data.
Separation of Phenols from the Leaves of Toona Sinensis (Meliaceae) by Capillary Electrophoresis
Authors: Hsieh Ming‐Mu , Chen Chung‐Yi , Hsieh Shu‐Ling , Hsieh Sung‐Fei , Lee Pak‐Hing Ben , Li Cheng‐Ta , Hsieh Tian‐Jye
Published: May 2015

A micellar electrokinetic capillary chromatography (MEKC) method, using UV detection, was developed for the determination of polyphenols in Toona sinensis (Meliaceae); the procedure involved precipitation of polyphenols from the leaves of T. sinensis using methanol. The structures can be established with fifteen compounds including methyl gallate, gallic acid, kaempferol, quercitin, quercitrin, rutin, kaempferol‐glucoside, catechin, epicatechin, stearic acid, palmitic acid, β‐sitosterol, stigmasterol, β‐sitosteryl‐glucoside, and stigmasteryl‐glucoside by spectroscopic analysis. However, there has been no investigation to quantitate the polyphenols that form T. sinensis. Thus, seven polyphenols of T. sinensis with UV absorbance, catechin (C), epicatechin (EC), methyl gallate (MG), rutin (R), gallic acid (G), quercitrin (Q), and kaempferol (K) were separated within 10 min with a 40 cm uncoated fused‐silica column, with the RSD < 3% (migration times), voltage at 15 kV using this method. On‐column detection was carried out at 254 nm. The detection limit of this method for all analytes ranged from 19.5 to 0.02 μM (RSD < 3.1%). The method provided a rapid and sensitive identification of polyphenols of interest in T. sinensis and is suitable for biological activity studies.
Synthesis of Phenanthridines by Flash Vacuum Pyrolysis of N‐benzylideneanilines
Authors: Hsu Yao‐Teng , Chou Chin‐Hsing
Published: May 2015

SS‐FVP of N‐benzylidene‐4‐methoxyaniline (3b) and FVP of N‐benzylidene‐2‐chloroaniline (3c)at 850–950 °C yielded phenanthridine (2) and its derivatives through gas phase electroncyclization.
Photoluminescence of I‐VII Semiconductor Compounds. Sensitized Luminescence from “Deep States” Recombination in CuBr/AgBr Nanocrystals
Authors: Hwang L. C. , Wei T.H. , Hsia Y. L. , Li C. M. , Tu P. L. , Wen T. C.
Published: May 2015

The photoluminescence (PL) properties of CuBr and CuBr/AgBr semiconductor nanocrystals (NCs) embedded in borosilicate glasses are measured under band‐to‐band excitation by a 355‐nm Nd YAG laser. We observed emission from CuBr (peaked at 520 nm) doped glass, which is associated with deep states in CuBr NCs. We also observed the sensitized blue to orange‐red emission in CuBr/AgBr‐glass systems (peaked at 520 and 570 nm), in which the luminescence intensity of CuBr decreases with increasing AgBr concentrations, while it is enhanced significantly around 570 nm. The results are discussed by the possible energy transfer between them, or by the multi‐exitonic recombination process which ejects an excited carrier from CuBr to AgBr NCs.
Computational Studies on Insertion Reaction of Germynes
Authors: Cheng Mu‐Jeng , Cheng Hsin‐Mei , Chu San‐Yan
Published: May 2015

This paper describes theoretical studies on the insertion reaction of germynes XC ≡ GeY (X,Y=H, Cl and F) at the carbon site into a C‐H bond of CH4 performed at the QCISD(T)/6–311G*//QCISD/6–31G* level of theory. This work was inspired by the observation by Sakamoto, Kira, and coworkers on the carbene‐like reaction mode for stannyne (RC≡SnR′). Due to the limitation in the computation for the tin atom, the study was carried out on germyne compounds instead. We found that the valence state of the germyne moiety in the transition state and reaction product can be well represented by the triplet germyne. It has a bifunctional electronic structure of a triplet cabene joined to a singlet germylene (Structure 1).
Two New 3D Networks Co(II) Complexes Constructed via the Bridging Dicyanamide and 2,2′‐Bipyrimidine Ligands: Structures and Magnetic Properties
Authors: Chen Chiu‐Wang , Wei Ho‐Hsiang , Lee Chin‐Jhan
Published: May 2015

Two new complexes [Co(bipym)(dca)](dca) (1) and [Co(bipym)(dca)]2(ClO4)2 (CH3OH)·2H2O (2) (dca = dicyanamide, bipym = 2,2′‐bipyrimidine) have been synthesized and their structuresl magnetically characterized. Complex 1 crystallizes in amonoclinic system P21/n space group, Z = 4, with a = 9.3710(2), b = 15.0690(3), c = 9.8920(2) Å, β = 92.4780(10)°. Complex 2 crystallizes in a monoclinic system C2/c space group, Z = 4, with a = 16.4190(3), b = 17.0880(3), c = 12.1130(2) Å, and β = 95.1070 (10)°. The crystal structure in 1 and 2 is a three‐dimensional network contraction through the bridging 1,5‐dca and bipym ligands. Temperature dependence of magnetic measurements show antiferromagnetic couplings in all cases with J = −7.22 for 1, and −7.11 cm−1 for 2, respectively.
Controlling Length and Monitoring Growth of Gold Nanorods
Authors: Chen Hao‐Ming , Liu Ru‐Shi
Published: May 2015

In this paper, we report a new approach, which could fabricate gold nanowires by controlling the volume of growth solution. The shape evolutions ranging from fusiform nanoparticles to 1‐D rods was observed. Increasing the addition of growth solution can control the length of nanorods. The length of rods can be extended to 2 μm, and nanorods with aspect ratios of up to ˜ 70 could be obtained. Moreover, X‐ray absorption spectroscopy (XAS) is applied herein to elucidate the growth mechanism of gold nanorods. The gold ions were directly reduced to gold atoms by ascorbic acid during the reaction, and then gold atoms were deposited on the surface of gold seeds that were introduced into the reaction. Extended X‐ray absorption fine structure (EXAFS) confirmed the growth of gold and the environment around Au atoms over the reaction. The XAS are expected to have wide applications in the growth of gold and other related materials.
Multi‐Channel Piezoelectric Crystal Gas Sensor with Principal Component Analysis for Organic Solvent Pollutants from Polymer Plants
Authors: Wang Ya‐Ling , Shih Jeng‐Shong
Published: May 2015

A multi‐channel piezoelectric (PZ) quartz crystal gas sensor coated with various organic adsorbents and a home‐made microcomputer interface for data processing have been fabricated for the detection of various organic vapors such as methanol, formic acid, propionaldehyde, carbon disulfide and N,N‐dimethyl formamide which are generally used as solvents in the polymer industry. The home‐made computer interface includes a digital Altera and an Intel‐8255 data processing system. The Principal Component Analysis (PCA) method was employed to analyze the frequency response signals from each channel with different coating materials and was applied to select the appropriate coating materials for these organic vapors. A dataset for the multi‐channel sensor with 29 PZ quartz crystals for these organic vapors was collected. Six representative coating materials such as C60‐polyphenyl acetylene (C60‐PPA), polyethylene glycol, Nafion, triphenyl phosphine, cryptand‐22 and polyvinyl pyrrolidone were selected after comparing the correlation between the 29 coating materials and the first four principal component (PC) factors of the PCA analysis. The 5 organic vapors can be effectively distinguished clearly by the six‐channel piezoelectric crystal sensor and which can be obviously found from the PCA Scores Map. Furthermore, different organic vapors tend to have distinguishing profile discrimination maps with the six channel PZ crystal sensor. The profile discrimination maps can be applied as fingerprints for these organic molecules. The six‐channel PZ crystal sensor has quite good detection limits for these organic vapors. Furthermore, the multivariate linear regression (MLR) analysis was also employed to compute the concentrations of methanol and carbon disulfide in the mixture of organic vapors.
Intramolecular Heck Reaction of Aryl Halide Tethered with Dienes as Acceptors: Studies of their 6‐endo‐trig versus 6‐exo‐trig Selectivities
Authors: Hon Yung‐Son , Hsu Yu‐Chia , Cheng Chia‐Yi
Published: May 2015

The palladium‐catalyzed intramolecular coupling reactions of aryl bromides tethered with conjugated dienoates give a 1 H‐isochromene ring system via 6‐endo‐trig cyclization almost exclusively. However, both 6‐endo‐trig and 6‐exo‐trig cyclizations are competitive processes in the palladium‐catalyzed intramolecular coupling reactions of aryl bromides tethered with conjugated dienones.
En Route to Improved Antimalarial Peroxides Following the Natural Role Model Artemisinin
Authors: Griesbeck Axel G. , El‐Idreesy Tamer T.
Published: May 2015

The synthesis of a series of 5‐cyclopropyl substituted 1,2,4‐trioxanes 3a‐3f by a sequence of singlet oxygen ene reaction with the 1‐cyclopropylated allylic alcohol 1 and subsequent peroxyacetalization reaction with aldehydes and ketones, respectively, is described. An important side reaction is the formation of cross‐peroxyacetalization products 4 and 5 from the Lewis‐acid catalyzed cleavage of the initially formed β‐hydroperoxy alcohol 2. The in vitro antimalarial activities of several derivatives 3 against Plasmodium falciparum are remarkably high.
Synthesis and Properties of Triptycene‐Diaminostilbene Hybrid Systems
Authors: Yang Jye‐Shane , Yan Jyu‐Lun
Published: May 2015

The synthesis, electronic spectra, and thermal and electrochemical properties of two triptycene‐capped trans‐4,4′‐diaminostilbenes (1Me and 1Ph) are reported in order to evaluate their applicability as blue light‐emitting materials in organic light‐emitting diodes (OLEDs). For comparison, the fluorescence properties of the planar analogs 2Me and 2Ph are also investigated. High fluorescence quantum yields (0.72–0.78) are observed for 1Me and 1Ph in THF, presumably due to a large barrier for the nonradiative double‐bond torsion reaction in the singlet excited state. In the spin‐cast thin films, the fluorescence quantum efficiencies become lower (0.15–0.26) and the fluorescence spectra are red‐shifted. Compared to 1Me and 1Ph, 2Me and 2Ph display even larger fluorescence shifts and fluorescence quenching, which can be attributed to their more planar structures that favor intermolecular π‐stacking in the solid state. The glass transition temperatures for 1Me and 1Ph are 113 and 120 °C, respectively, and the decomposition temperatures 341 and 375 °C, respectively. Cyclic voltammograms of 1Me and 1Ph show two reversible redox waves, corresponding to two monoelectronic oxidation processes of the amino groups forming radical cation and dication species.
(2,2′‐Bipyridine)palladiumdichloride Derivatives as Recyclable Catalysts in Heck Reactions
Authors: Lu Norman , Chen Jeng‐Yung , Fan Chi‐Wen , Lin Yan‐Chou , Wen Yuh‐Sheng , Liu Ling‐Kang
Published: May 2015

Fluorous ponytailed [PdCl2(4,4′‐bis(RfCH2OCH2)‐2,2′‐bpy)], (Rf = CF3(CF2)2 2a, HCF2(CF2)3 2b, HCF2(CF2)7 2c, and non‐fluorous [PdCl2(4,4′‐bis(CH3)‐2,2′‐bpy)] 3 were prepared and successfully employed in the catalyst reusage studies running the homogeneous Heck reaction of C6H5I and H2C=CHCO2CH3, the catalysts being recycled for 8 consecutive runs without loss of activity and the recovery procedure being the direct vacuum distillation of mixtures to take advantage of the very high thermal stability of these PdCl2(2,2′‐bpy) derivatives.
Catalytic Reaction of Para‐Isopropylbenzaldehyde with Propionaldehyde over Solid Base Catalysts
Authors: Shiau Shin Yi , Ko An‐Nan
Published: May 2015

3‐(4‐Isopropyl‐phenyl)‐2‐methyl‐acrylaldehyde (4IP2MA) was synthesized from propionaldehyde (PA) and para‐isopropylbenzaldehyde (IPB) via cross aldol condensation over alkaline earth metal oxides or Al2O3‐MgO mixed oxides (AM) at 120–190 °C by using a batch reactor. The catalytic activity is enhanced with the base amounts of both alkaline earth metal oxides and the mixed oxides. The reaction system is free of diffusional limitation at a stirring speed larger than 600 rpm. Increasing the catalyst weight, reaction temperature, reaction time and IPB/PA mol ratio enhances the PA conversion, whereas the 4IP2MA selectivity remains small change except for IPB/PA ratio. Favorable results occur on the PA conversion and the 4IP2MA selectivity for the reaction in nonpolar solvents of cyclohexane and benzene. Reused catalysts of MgO and AM exhibit no catalyst decay. For the formation of 4IP2MA, the reaction mechanism is proposed and the apparent activation energy is calculated.
Synthesis and Biological Evaluation of 5′‐Triazole Nucleosides
Authors: Lee Lenselot , Chang Kai‐Hsuan , Valiyev Famil , Liu Hsing‐Jang , Li Wen‐Shan
Published: May 2015

The first series of 5′‐triazole cytidines 1a‐d and adenosines 2a‐c was prepared and evaluated for inhibitory potency toward α‐2,3‐sialyltransferase. The synthesis of target compounds was achieved by converting the 5′‐alcohol of protected nucleosides to the azide derivatives, which were then coupled with the alkynes by copper(I)‐catalyzed cycloaddition to give protected 5′‐triazole nucleosides 3a‐d/7a‐c, followed by deprotection. 5′‐Triazole adenosines 2a‐c were less efficient inhibitors of α‐2,3‐sialyltransferase than their cytidine analogues 1a‐d. 1d was the most active compound with an IC50 of 37.5 μM. These results suggested that the hydrophobic functionality and the cytidine group are clearly required for the improved binding.
Synthesis and Anti Tuberculostatic Activity of Novel 1,3,4‐Oxadiazole Derivatives
Authors: Yar M. Shahar , Siddiqui A. Ahmad , Ashraf Ali M.
Published: May 2015

A series of novel 2,5‐disubstituted 1,3,4‐oxadiazole derivatives were synthesized and tested for their in vitro antimycobacterial activity. Some compounds showed interesting activity against a strain of Mycobacterium tuberculosis H37Rv. The result of the antimycobacterial activity tests revealed that 2‐(2‐naphthyloxymethyl)‐5‐phenoxymethyl‐1,3,4‐oxadiazole (IVd) exhibited > 90% inhibition at MIC ˜6.25.
Calculation of the Viscosity of Simple Fluids Based on the Rainwater‐Friend Theory
Authors: Hashemi Fariba S. , Tafreshi Saideh S.
Published: May 2015

Viscosities of noble gases have been calculated over a wide temperature‐pressure range. Simple and accurate Tang‐Toennies potential of the noble gases are used in the Chapman‐Enskog calculation of the zero density viscosity and in the Rainwater‐Friend theory to determine the initial density dependence of the viscosity. At densities beyond the range of the theory (up to 46 mol.dm−3), a variant of the residual viscosity is developed. A correlation function for the calculation of viscosity over the whole range of density is presented. A comparison of the calculated and experimental values of the viscosity yields an average absolute deviation of 1.5%.
Spherical Zinc Oxide Nano Particles from Zinc Acetate in the Precipitation Method
Authors: Hsieh Cheng‐Hsien
Published: May 2015

The liquid precipitation method using zinc acetate dihydrate was applied for the synthesis of uniform and spherical ZnO nanoparticles. The ultrafine zinc oxid was prepared in a water‐ethanol mixture solution. The solution containing zinc cation was soluble in water. The surface‐active agent triethanolamine (TEA) was soluble in ethanol. Then alkali precipitated by adding n‐propylamine. The spherical zinc oxide particle morphology was found to be highly dependent on the zinc salt concentration, ethanol‐water ratio, and the surface‐active agent additive. The process can produce white ZnO powder of 50–90 nm in size. The morphology of zinc oxide showed a powder shape by transmission electron microscopy (TEM), the crystallization phase structure of zinc oxide by X‐ray diffraction (XRD), and the zinc oxide remaining by using an organic analysis by infrared spectroscopy (IR).
Control of Wall Thickness and Extraordinarily High Hydrothermal Stability of Nanoporous MCM‐41 Silica
Authors: Cheng Chi‐Feng , Chou Shu‐Hsien , Cheng Po‐Wen , Cheng Hsu‐Hsuan , Yak Hwa‐Kwang
Published: May 2015

Wall thickness of siliceous MCM‐41 could be controlled systematically up to 36.1 Å. A reasonable model explaining formation of thicker MCM‐41 walls, not enlarging pore channel is proposed on the basis of TGA and 13C MAS NMR data of samples. Thermal restructuring process under mild basic condition favors the silica redeposition on silica wall and building up thicker wall. Most mesostructure of calcined MCM‐41 with thicker wall was retained even after hydrothermal treatment in boiling water for 14 days. To our best knowledge, the excellent hydrothermal stability of the MCM‐41 silica reported herein has not been described before and facilitates practical applications of mesoporous molecular sieves in future.
Development and Evaluation of a Kinetic‐Spectrophotometric Method for Determination of Arginine
Authors: Mitić Snežana S. , Miletić Gordana Ž. , Pavlović Aleksandra N. , Tošić Snežana B. , Velimirović Dragan S.
Published: May 2015

A kinetic method for the determination of micro quantities of amino acid arginine (Arg) is described in this paper. The catalytic activity of cobalt in the reaction of oxidation of purpurin (1,2,4‐trihydroxy‐antraquinone, PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of arginine, because of the formation of the complex. Operating conditions for the successful determination of arginine were optimized. The optimized conditions yielded a theoretical detection limit of 1.45 μg mL−1. Kinetic equations are proposed for the investigated process. The interference effects of certain foreign ions and amino acids upon the reaction rate were studied and removed in order to assess the selectivity of the method. The developed procedure was successfully applied to the determination of arginine in various pharmaceutical samples. The typical feature of this procedure is that determination can be carried out at room temperature and in a short analysis time. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of samples.
Novel Metronidazole Membrane Sensor Based on a 2,6‐(p‐N,N‐Dimethylaminophenyl)‐4‐Phenylthiopyrylium Perchlorate
Authors: Ganjali Mohammad Reza , Norouzi Parviz , Faridbod Farnoush , Pirelahi Hooshang
Published: May 2015

A novel PVC‐based membrane sensor based on 2,6‐(p‐N,N‐dimethylaminophenyl)‐4‐phenylthiopyrylium perchlorate (DAPP) is described. The electrode exhibits a sub‐Nernstian response to 1‐(beta‐hydroxyethyl)‐2‐methyl‐5‐nitroimidazole (metronidazol) over a relatively wide concentration range (1.0 × 10−1 to 1.0 × 10−5 M) with a detection limit of 8.0 × 10−6 M. The best performance was obtained with the membrane containing 30% poly (vinyl chloride), 50% dibutyl phthalate, 7% DAPP and 13% oleic acid. It has a fast response time (< 30 s) and can be used for at least four weeks without any major deviation. The proposed sensor revealed very good selectivity for metronidazole over a wide variety of common cations, anions and amino acids and could be used in the pH range of 6.0–7.5. It was successfully used for direct determination of metronidazole in an oral synthetic antiprotozoal as an antibacterial agent, in metronidazole tablets, and metronidazole injections and metronidazole gels.
Determination of Cinnarizine in Pure and Pharmaceutical Formulations
Authors: Devagondanahalli Manjunatha Hadagali , Shaikh Sarfaraj Mohd Takhi , Jaldappagari Seetharamappa , Ramanaboyina Sudhir Kumar , Kasalanti Harikrishna
Published: May 2015

Two simple, rapid and sensitive extractive spectrophotometric methods have been developed for the assay of cinnarizine (CNR) in pure and pharmaceutical formulations. The methods are based on the formation of chloroform soluble ion‐association complexes of CNR with thymol blue (TB) and with cresol red (CR) inNaOAc‐AcOH buffer of pH 3.6 for TB and in KCl‐HCl buffer of pH 1.6 for CR with absorption maxima at 405 nm and at 403 nm for TB and CR, respectively. Reaction conditions were optimized to obtain the maximum color intensity. The systems obeyed Beer's law in the range of 0.6–15.8 and 0.8–16.6 μg mL−1 for TB and CR, respectively. Various analytical parameters have been evaluated and the results have been validated by statistical data.
Expression, Purification and Characterization of a Bifunctional α‐L‐Arabinofuranosidase/β‐D‐Xylosidase from Trichoderma Koningii G‐39
Authors: Wan Chin‐Feng , Chen Cheng‐Ta , Li Yaw‐Kuen , Huang Lina
Published: May 2015

A gene of α‐L‐arabinofuranosidase (Abf) from Trichoderma koningii G‐39 was successfully expressed in Pichia pastoris. The recombinant enzyme was purified to > 90% homogeneity by a cation‐exchanged chromatography. The purified enzyme exhibits both α‐L‐arabinofuranosidase and β‐D‐xylosidase (Xyl) activities with p‐nitrophenyl‐α‐L‐arabionfuranoside (pNPAF) and 2,4‐dinitrophenyl‐β‐D‐xylopyanoside (2,4‐DNPX) as substrate, respectively. The stability and the catalytic feature of the bifunctional enzyme were characterized. The enzyme was stable for at least 2 h at pH values between 2 and 8.3 at room temperature when assayed for Abf and Xyl activities. Enzyme activity decreased dramatically when the pH exceeded 9.5 or dropped below 1.5. The enzyme lost 35% of Abf activity after incubation at 55 °C for 2 h, but retained 95% of Xyl activity, with 2,4‐DNXP as substrate, under the same conditions. Further investigation of the active site topology of both enzymatic functions was performed with the inhibition study of enzyme activities. The results revealed that methyl‐α‐L‐arabinofuranoside inhibition is noncompetitive towards 2,4‐DNPX as substrate but competitive towards pNPAF. Based on the thermal stability and the inhibition studies, we suggest that the enzymatic reactions of Abf and Xyl are performed at distinct catalytic sites. The recombinant enzyme possesses both the retaining transarabinofuranosyl and transxylopyranosyl activities, indicating both enzymatic reactions proceed through a two‐step, double displacement mechanism.
A New Application of Hexamethylenetetramine‐Bromine Supported onto Wet Alumina as an Efficient Reagent for Cleavage of Phenylhydrazones under Classical Heating and Microwave Irradiation
Authors: Heravi Majid M. , Sabaghiani Ali J. , Bakavoli Mehdi , Ghassemzadeh Mitra , Bakhtiari Khadijeh
Published: May 2015

2,4‐Dinitrophenylhydrazones were converted to their parent carbonyl compounds using hexamethylenetetramine‐bromine complex supported onto wet alumina under classical heating and microwave irradiation.
Photoinduced Aromatization of Unsymmetrically Substituted 1,4‐Dihydropyridines
Authors: Memarian Hamid R. , Abdoli‐Senejani Masumeh , Döpp Dietrich
Published: May 2015

Irradiation of unsymmetrically substituted 1,4‐dihydropyridines (1b‐1j) while bubbling oxygen or argon through the solution resulted in aromatization to the corresponding pyridine derivatives (3b‐3j). Compound 1a with 2‐nitrophenyl substituent in 4‐position undergoes elimination of water upon irradiation under both oxygen and argon atmospheres and formation of 3a with 2‐nitrosophenyl substituent. On the other hand, irradiation of the compounds 1e, 1k and 1l with 4‐hydroxy‐3‐methoxyphenyl, 5‐methyl‐2‐furyl and 2‐furyl substituent in this position, respectively, resulted in the expulsion of these substituents and formation of a pyridine derivative unsubstituted in position 4, namely compound 2. Chloroform as a solvent causes the photo‐oxidation of these compounds by an electron transfer mechanism which is supported by the formation of dichloromethane according to GC analysis and presence of acid (HCl) in the solution after irradiation.
Simultaneous Determination of Nickel(II) and Copper(II) by Second‐Derivative Spectrophotometric Method in Micellar Media
Authors: Pouretedal Hamid Reza , Rafat Marym
Published: May 2015

A second‐derivative spectrophotometric method based on zero‐crossing over technique is developed in simultaneous determination of copper(II) and nickel(II) ions. Methylthymol blue (MTB) as a chromogenic reagent and cetyltrimethylammonium bromide as a surfactant were used, and measurements were carried out in buffered solution at pH 6 and at a temperature of 25 °C. The amplitude of derivative spectra was measured at wavelengths of 631.9 and 587.7 nm for the simultaneous determination of Ni2+ and Cu2+, respectively. Linearity was obtained in the range of 0.5–5.0 μg mL−1 for both ions in the presence of 0.0–5.0 μg mL−1 of the other ion as an interfering ion. IUPAC detection limits for Cu2+ and Ni2+ ions were obtained at 0.48 and 0.43 μg mL−1, respectively. The proposed procedure has been applied successfully for the simultaneous determination of copper and nickel in synthetic binary mixtures and real samples.