bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complexes of N‐(2 Hydroxy‐1‐Naphthalidene) Antharanilic Acid with Some Lanthanides
Authors: Abou Ali S. A. , Ali G. Y. , Osman M. M. 
Published: June 2015

AbstractThe complexes of N‐(2‐hydroxy‐1‐naphthalidene)anthranilic acid abbreviated (H2NA) with some trivalent rare earth elements (Pr, Nd, Sm, Gd, Dy, Er and Yb) were prepared. The complexes were characterized by chemical and thermal analysis, ir and conductimetric methods. Two types of ionic complexes; Ln(HNA)2OH·2H2O with Dy, Er and Yb, and Ln(HNA)2OH with Pr, Nd, Sm and Gd were isolated. Coordination of the ligand with metal‐ions occurs through the carboxy group and the nitrogen atom. The acid dissociation constants K1 and K2 of H2NA and the overall stability constants β1 and β2 of some lanthanide complexes in 75% (v/v) dioxan‐water solutions were determined by the potentiometric method.
Atomic Absorption Spectrophotometric Determination of Copper(II) after Adsorption of its Oxinate on Microcrystalline Naphthalene
Authors: Lin Jenn‐Lin , Chang Lih‐Fen 
Published: June 2015

AbstractA New Atomic Absorption Spectrophotometric Procedure Has Been Developed For The Microdetermination Of Copper(Ii) As Its Oxinate By Its Adsorption On Micro‐Crystalline Naphthalene And Dissolution In 1 N Nitric Acid. Copper(Ii) Oxinate Is Quantitatively Adsorbed In The PH Range Of 3.2–10.1 And Trace Amounts Of Copper Can Be Determined. The Effect Of Variables Such As Reagent And Naphthalene, Shaking Time, Digestion Time, And Diverse Ions Are Studied. The Proposed Method Has Been Applied To The Determination Of Copper In Standard Reference Material (Zinc Alloy), And Metallic Zinc And Lead.
Constituents of the Peel of Citrus Depressa Hayata
Authors: Wu Tian‐Shung , Kuoh Chang‐Sheng , Wang Chao‐Hsiung , Tien Hsien‐Ju 
Published: June 2015

AbstractEleven known compounds; methyl‐3,4‐dihydroxycinnamate, pyrocatechuic acid, isoimperatorin, naringenin, umbelliferone, pyrocatechol, meranzin hydrate, neohesperidin, narirutin, friedelin, β‐sistosterol were isolated and characterized from the peel of Citrus depressa Hayata.
Synthesis and Reactions of Some 1‐Thiapyran‐4‐One Derivatives
Authors: El‐Barbary A. A. , Abdel‐Megeid F. M. E. , Gad F. A. 
Published: June 2015

AbstractThe preparation of some 3,5‐diarylidene‐1‐thipyran‐4‐one derivatives (Ia‐e) was described. Oxidation of Ia, b and Ie with hydrogen peroxide gave the corresponding dioxides (IIa‐c). Reaction of the 1‐thiapyran‐4‐one derivatives with bromine, Grignard reagents, and amines were studied. Structural assignments are supported by spectral (UV, IR, and 1HNMR) data.
The Structure of Suginal from the Wood of Juniperus Formosana Hayata
Authors: Kuo Yueh‐Hsiung , Chen Wen‐Chan , Wu Tseng‐Rong 
Published: June 2015

AbstractThe detailed investigation of the acetone extract from the wood of Juniperus formosana Hayata gave a new diterpene aldehyde which was elucidate as suginal on the basis of chemical and spectroscopic evidence.
On the Proper Normalization Constraint
Authors: Chang Tse‐Chiang 
Published: June 2015

AbstractIn the variational optimization of a trial function the proper functional to be varied is the Rayleigh quotient with the normalization constraint explicitly imposed. It will be shown that only under certain very rigorous conditions can one use the energy functional to replace the Rayleigh quotient and that, therefore, the normalization constraint is by no means a matter of no consequence.
Kinetics of the Ruthenium‐Catalyzed Hydrogenation of Acetic Acid to Ethanol
Authors: Shih Yen‐Shiang , Lee Chang‐Keng 
Published: June 2015

AbstractThe ruthanium‐catalyzed hydrogenation of acetic acid to ethanol was conducted at 140–230° under hydrogen pressure of 40.8–81.6 atm with a catalyst loading of 4 g/L. The best rate expression to fit the experimental results isKinetic data at 230° were obtained with an average error of 7%. It is concluded that the rate limiting step is the first addition of hydrogen to acetic acid to produce aldehyde and water as the intermediates. The activation energy is 12.7 kcal/mole.
The Stabilities of the o‐Carboxyphenylhydrazo‐Ethylacetoacetate OF Cu, Ni, Co, Zn, Mn and Cd Chelate Compounds in Different Solvents
Authors: El‐Shetary Basheir A. , Zahra Ahmed M. , Taha Atef A. , Ibrahim Aesha I. 
Published: June 2015

AbstractThe dissociation constants for o‐carboxyphenylhydrazoethylacetoacetate (o‐CPHEA) ligand, as well as the stability constants for the divalent metal complexes of Cu, (II), Ni (II), Co (II), Zn (II)and Cd (II) ions, have been calculated pH‐meterically in different solvents. The dissociation constans pK1=4.10 and pK2=10.55 of the insoluble organic ligand are calculated in aqueous medium. The effect of solvents, the relation between stabilities and both electronegativities and ionization potential are studied.
A Polarographic Study of ϵ‐Caprolactam Complexes of Uranium and Tellurium
Authors: Puri B.K. , Kumar Ashok , Rao A.L.J. 
Published: June 2015

AbstractThe polarographic behaviour of uranium and tellurium has been studied in the presence of increasing concentration of complex forming agent viz. ϵ‐caprolactam at pH 4.4 for U(VI) and at pH 10.0 for Te(IV) at μ=0.1 M KNO3. In both cases the waves have been found to be diffusion controlled and irreversible. The values of kinetic parameters (σπa and K°f,h) have been calculated as a function of the ligand concentration. Method is suitable for the quantitative determination of these metals individually and simultaneously with the effect of diverse ions.
The Structure of Taiwanin F from Taiwania Cryptomerioides Hayata
Authors: Kuo Yueh‐Hsiung , Chen Wen‐Chau , Lin Yau‐Tang 
Published: June 2015

AbstractReinvestigation of the nonvolatile fraction of the acetone extractive from the heartwood of Taiwania cryptomerioides Hayata afforded taiwanin F which was established as 11‐hydroxy‐7‐oxohinokiol on the basis of spectral data and its synthesis from hinokiol. In addition, six known compounds, taiwanin A, savinin, taiwanin C, hinokiol, taiwanin E and diphyllin were also isolated from the same fraction.
The Chemical Constituents of the Peel of Citrus Tankan Hayata
Authors: Cheng Yu‐Shia , Lee Chih‐Shone , Chou Chun‐Tzer , Chang Chi‐Feng 
Published: June 2015

AbstractSeven kinds of flavones, β‐sitosterol, β‐sitosterol‐D‐glucoside, hesperidin, limonin, ferulic acid and succinic acid were isolated from the fruit peel of Citrus tankan Hayata.
Chelating Behaviour of Substituted 3‐4 Aryl‐Hydrazo‐Pentane‐2, 4‐Dione: Part VI. Potentiometric and Infrared Studies of the Ligands and Their Divalent Metal Complexes
Authors: El‐Shetary B. , El‐Inany G. A. , Issa Y. M. , Taha Atef A. 
Published: June 2015

AbstractThe dissociation constants of 3‐phenylhydrazo‐pentane‐2, 4‐dione and its o‐, m‐, p‐carboxy derivatives, and the stability constants of complexes of divalent metal ions with the o‐carboxy derivative are determined by pH‐metric method. The ir‐spectra of the ligands and some divalent metal complexes with the o‐derivative are discussed.
Preparation of Three Decadeoxyribonucleotides Containing an Uncommon or Modified Base
Authors: Chandrasecaran S. , Kan L. S. 
Published: June 2015

AbstractThree decadeoxyribonucleotides (d‐C‐C‐A‐A‐I‐A‐T‐T‐G‐G, d‐C‐brC‐A‐A‐G‐A‐T‐T‐G‐G and d‐C‐C‐A‐A‐mG‐A‐T‐T‐G‐G) involving inosine (I), 5‐bromocytidine (brC) and 6‐O‐methylguanosine (mG) were chemically synthesized based on the phosphotriester approach in milligram quantities. The procedures of full protection reaction of these uncommon or modified bases are given in detail. The phosphotriester method was then employed to synthesize all the decamers. It seems the phosphotriester method is applicable to the synthesis of oligodeoxyribonucleotide with these three odd‐bases. However, slightly different procedures have to be used while deblocking the fully protected oligodeoxyribonucleotides depending upon the nature of the uncommon or modified base.
Determination of Elastic Moduli and Compliances of Viscoelastic Liquids Using the Dynamic Light Scattering Technique
Authors: Wang C. H. 
Published: June 2015

AbstractRelations between the dynamic light scattering spectrum and the mechanical compliances and longitudinal stress moduli of viscoelastic liquids are provided. The result provides a basis for determination of mechanical relaxation spectra using the dynamic light scattering technique. The method of Computating the longitudinal modulus and the compliance spectra from the time correlation of density fluctuations of poly (propylene glycol), as determined by the photon correlation spectroscopy technique is illustrated.
Crystal Structure of [Co2(μ‐dmg)2(μ‐dmg H)(dmg H)(Pø3)] 1/2 dmg H2 · 1/2 CH3OH: A Crystal Containing Various Forms of dmg Ligand
Authors: Peng Shie‐Ming , Shauo Chung Dung , Wang Yu 
Published: June 2015

AbstractThe crystal structure of [Co2(μ‐dmg)2(μ‐dmg H)(dmg H)(Pø3)] · 1/2 dmg H2 · 1/2 CH3OH has been determined by single crystal X‐ray diffraction. The title complex crystallizes in triclinic space group P&1bar; with a=10.859(3), b=13.299(3), c=15.247(3)Å, α=98.52(2), β=99.26(2), γ=97.80(2)° and Z=2. The agreement indices are R(F)=0.062 and Rw(F)=0.085 for 5231 observations and 515 variables. Both cobalt atoms have an oxidation state of 3+ and are both six‐coordinated; one Co(III) atom is bonded to a phosphorous atom of triphenylphosphine, four nitrogen atoms of two planar ligands, dmg2− and dmgH−, and one oxygen atom of another dmg2− ligand. The other Co(III) atom is coordinated by four nitrogen atoms of two cis nonplanar ligands, dmg2−, dmgH−, and two oxygen atoms of the other dmg2− and dmgH− ligands. There are three N‐O bridged ligands namely two dmg2− and one dmgH− between two Co(III) atoms. A free molecule of dmgH2 and a molecule of CH3OH are also found in the crystal lattice. The structure interestingly demonstrates the possible various forms of dmg, not only on their charge but also in different conformations upon coordination.
Detection of the Sulfhydryl Group in Proteins by Raman Scattering Spectroscopic Method
Authors: Tu Anthony T. 
Published: June 2015

AbstractDetection of the sulfhydryl group in proteins has previously been difficult. However, the group can be detected quite easily by Raman spectroscopy due to its distinct vibrational band at 2560‐2580 cm−1 region. This region is free of interference from other vibrational bands of protein. Detection of SH in tobacco mosaic virus coat protein and two sea snake neurotoxins was made to illustrate the application of Raman spectroscopy.
Chemical Synthesis of Oligodeoxyribonucleotides on the Polystyrene Polymer Support
Authors: Chandrasegaran Srinivasan , Kan Lou‐Sing 
Published: June 2015

AbstractThe synthesis of a decaeoxyribonucleotide, d‐CpCpApApTpTpTpTpGpG, as an example of DNA synthesis on a polystyrene polymer support using the phosphotriesters is described. The procedures for the recovery of the unreacted protected nucleoside phosphotriesters are also included. All operations and reactions were carried out in a 4 ml polypropylene Bio‐Rad Econo column fitted with a 3‐way teflon valve and a rubber septum. The average yield of each monomer addition is 96%. The decamer was obtained in high purity with an isolated yield of 56%. The purified decamer was characterized using a modified Maxam‐Gilbert procedure.
Solvent Effect on the Kinetic Study of the Alkaline Hydrolysis of Formamide in Acetone‐Water Mixtures
Authors: Salem S.M. , Sidahmed I.M. 
Published: June 2015

AbstractThe specific rate constants for the alkaline hydrolysis of formamide were determined in a series of acetone‐water mixtures ranging from 0.0% to 70% by weight of the organic solvent and at different temperature, 25°–50°. The rate was found to be larger in water. Addition of acetone appears to cause a change in the solvent structure as concluded from the variation of log k with either 1/D or log[H2O]. The reactivity of the reactants and the activated state seems to be affected differently by a change in the solvent structure. The magnitude of such effect should be considered separately on both the reactants and the activated state in order to account for the increase of the rate as the dielectric constant of the medium is increased.
A Study of the Sydnone Compounds: Bromination and Chlorination(III)
Authors: Tien Hsien‐Ju , Yeh Mou‐Yung , Huang Chun‐Yin 
Published: June 2015

AbstractA convenient method for the bromination or chlorination of 4‐unsubstituted sydnone with NBS or NCS in DMF solution was carefully investigated. Tweleve bromo‐compounds (yield 74‐96%) and seven chloro‐compounds (yield 75‐93%) were obtained.
A‐Study of the Constituents of the Bark of Tsuga Chinensis Pritz. Var. Formosana (Hay.)
Authors: Fang Jim‐Min , Wu Shih‐Kwang , Cheng Yu‐Shia 
Published: June 2015

AbstractThe bark of the Taiwan hemlock was found to contain long‐chain alcohols, acids and esters, campesterol, β‐sitosterol, 13‐epimanool, larixol, dihydroconiferyl alcohol and the corresponding esters, p‐hydroxybenzoic acid, kaempferol, epiafzelechin, epicatechin and a novel compound of (3,5‐dihydroxy‐2‐methyl)phenyl 4′‐hydroxybenzoate.
Trace Analysis of Nickel by Extraction‐Atomic Absorption Spectrophotometry Determination of its Acenaphthenequinone Dioxime Complex in Molten Naphthalene
Authors: Lin Jenn‐Lin 
Published: June 2015

AbstractA procedure is described for the trace analysis of nickel using the liquid‐liquid extraction of nickel acenaphthenequinone dioxime complex with molten naphthalene followed by solid‐liquid separation. Nickel complex cannot be extracted into any non‐aqueous organic solvents, but can be quantitatively extracted into molten naphthalene. It is very stable at high temperature and is dissolved in the mixed solvent (HNO3‐DMF). The absorbance of the solution was measured at 231.5 nm against a reagent blank. Beer's law is followed in the concentration range of 5–100 μg of nickel in 10 ml of the final solution. The sensitivity for 1% absorption is 0.155 μg/ml nickel. The relative standard deviation is 1.0% for ten replicate determinations of 60 μg of nickel. The interference of various ions has been studied and the method has been applied to the determination of nickel in aluminium alloys.
Comparative Study of Some Methods for the Determination of the Analgesic Anti‐Inflammatory Compound “IS4”: 4‐(Anisylideneamino) Antipyrine
Authors: Shukrallah I. Z. , Sakla A. B. 
Published: June 2015

AbstractA comparative study of some quantitative methods has been undertaken. Chemical and colorimetric procedures have been developed for the determination of IS4: 4‐(anisylideneamino) antipyrine. The non‐aqueous titration and the nitritometric techniques were used. The formation of colored azo dye derivatives through diazotization and coupling with phenolic and amine reagents has been the basis of the colorimetric determination. Statistical analysis of the results has shown that a good agreement of the results has been found on applying the proposed methods to 4‐aminoantipyrine.
Preparation of σ‐ and π‐Benzyl Type Derivatives of Molybdenum
Authors: Lin See , Lin C. Y. , Wang H. Y. 
Published: June 2015

AbstractThe reaction of ‐LiM0(CO)2Cp with α‐chloromethylnaphthalene gives a yellow, crystalline σ‐benzyl type derivative of molybdenum (1). Irridation of (1) in n‐hexane gives a red π‐benzyl type derivative (2). Both complexes (1) and (2) are stable in air.
The Effect of Perchloric Acid on the Mössbauer Parameters of tin‐119 in Frozen Solutions
Authors: Cheng H. S. , Hsu C. M. , Chen M. Y. , Luh H. 
Published: June 2015

AbstractThe Mössbauer parameters of frozen solutions of 0.05 M Sn(H2O)(ClO4)2, Sn(H2O)3(ClO4)4, SnCl4·5H2O, SnBr4 and Na2SnBr6 [designated as Sn(H2O)N‐N, L(x‐N')+N, in which N≤N; N' = N = 6 for SnBr2−6, N′=4 with N=6 for Sn(H2O)2(ClO44 Sn(H2O)2Cl4 and Sn(H2O)2Br4 and N′=2 with N=3 for Sn(H2O)(ClO44)2] were found to be linearly related to the concentration (c) of perchloric acid. These facts were attributed to a change in activity of water (aw). At c=O, aw=1, the Mössbauer parameters corresponded to Sn(H2O)z+N, whereas at c=11.6 M (70%), they corresponded to the crystalline state of Sn(H2O)N‐N, L(z‐N)+N+. It was shown that even ClO−4 ion could coordinate to tin atom in perchloric acid. The degree of association at any given c could be estimated very easily through the relation . It was emphasized that the activity of water should be taken into account when equilibrium studies were carried out in perchloric acid solutions. Further corrections for perchlorate complex formation should be made, if a very weak ligand was added into metal perchlorate solutions.
Kinetics and Mechanism of Oxidation of 1‐Phenylsemicarbazide by Peroxydisulphate
Authors: Amira M. F. , Iskander M. F. , El—Shazly SH. A. , Abdel—Halim F. M. 
Published: June 2015

AbstractKinetics of oxidation of 1‐phenylsemicarbazide (PSC) by peroxydisulphate ion (PDS) have been carried out where by the pseudo first order condition was verified at large excess of PDS concentration. The rate of the reaction was followed spectrophotometrically, The stoichiometry was found to be 1:1 where 1‐phenylazoformamide is the oxidation product. The effect of acidity on the rate of oxidation was investigated for different temperatures. The parameters of activation ΔG*, ΔH* and ΔS* were computed for both hydrogen ion depedent and hydrogen ion independent reaction pathes. A free radical mechanism was proposed.
Equilibrium and Kinetic Aspects of Hg(II) Extraction from Natural Waters with Diphenylthiocarbazone
Authors: Jaffar M. , Ashraf M. 
Published: June 2015

AbstractA diphenylthiocarbazone (dithizone) based liquid‐liquid extraction method of general utility is proposed for small‐scale Hg(II) extraction from natural waters. The quantitative aspects related to the extraction are studied in terms of distribution of mercury dithizonate in carbon tetrachloride‐water system at 293 K (20±1°C). Various distribution constants related to the reagent and the complex formed are evaluated. The equilibrium and kinetic studies of extraction and complex formation are analytically based on atomic absorption and colorimetric methods. Local natural waters were subjected to the proposed method for Hg(II) removal. The method is found to be capable of removing above 98% mercury in a single‐step extraction under the conditions evaluated in terms of matrix pH, equilibration time and amount of reagent.
Chelate Compounds of a Selected Non‐Transition and Transition Metal Ions with Some Salicylic Acid Derivatives
Authors: El‐Gaber A. A. Abd , El‐Roudi A. M. , Soliman E. M. , Mahmoud M. R. 
Published: June 2015

AbstractA series of binary complexes of Zn(II), Hg(II), Pb(II), La(III), Ce(III), Th(IV) and UO2(II) with 3,5‐dinitrosalicylic acid and 5‐sulphosalicylic acid have been isolated and characterized. The solution equilibria of these complexes have been studied pH‐metrically. The formation constants (log K) at 25±1°C and ionic strength of 0.2M NaClC4 have been calculated. Stability of the complexes formed in relation to ligand molecular structure and nature of the metal ion has been examined and discussed.
Physico‐Chemical Stability of Warfarin in Ground Mixtures with β‐Cyclodextrin or Microcrystalline Cellulose under Storage Conditions
Authors: Lin Shan‐Yang , Kao Yuh‐Horng 
Published: June 2015

AbstractThe effects of grinding and the excipients used on the solid state stability of warfarin in ground mixtures with β‐cyclodextrin or microcrystalline cellulose have been investigated by using x‐ray powder diffractometry, IR spectrophotometry and differential scanning calorimetry. The grinding process did not result in warfarin‐excipient interaction, but caused a crystalline form of warfarin to transfer to an amorphous state in the presence of β‐cyclodextrin. The stability of this amorphous state of warfarin in tablets made from the ground mixtures stored at 37°C and 75% RH (relative humidity) was also studied. There was only a small amount of amorphous warfarin in tablets that recrystallized under storage conditions. The recrystallization of amorphous warfarin might be due to moisture adsorption. β‐cyclodextrin possesses an ability to prevent the recrystallization of large amounts of amorphous warfarin in tablets stored at 37°C and 75% RH.
The Preparation of Heptacyclo[6.6.0.0.2,60.3,130.4,11 0.5,90.10,14]Tetradecane Derivatives and the Analysis of Their NMR Spectra
Authors: Chow Tahsin J. , Feng Jung‐Jung , Shih Huey‐Jen , Wu Tung‐Kung , Tseng Li‐Hong , Wang Chi‐Ying , Yu Chin 
Published: June 2015

AbstractThe title compound is functionalized by a series of reactions to yield derivatives in the forms of hydroxides, ketones, ketals, lactones, etc. Their structures are analyzed by NMR spectroscopy.
A Practical Formal Synthesis of a Physiologically Active Analogue of Platelet Activating Factor
Authors: Tsai Yeun‐Min , Jiang Shu‐Li , Chen Huei‐Ju , Chau Lee‐Young , Lin Jin‐Tay 
Published: June 2015

AbstractA synthesis of phosphocholine 9 was accomplished in 36% yield from isopropylidene glycerol in contrast to 2% yield as reported previously. Since 9 has been converted to platelet activating factor‐analogue 2, this report constitutes a more practical synthesis of 2.
Comment on ‘Topological Analysis of the Eigenvalues of the Adjacency Matrices in Graph Theory: A Difficulty with the Concept of Internal Connectivity’
Authors: Lee Shyi‐Long 
Published: June 2015

AbstractNet signs of edge‐signed graphs obtained for different choices of degenerate eigenvectors of an adjacency matrix are shown to become equal with a simple weighting procedure. However, in a few cases, this simple procedure is found to yield orderings of the eigenvectors based on the weighted net signs which are different from the orderings based on the eigenvalues.
Crystal and Molecular Structures of (η4‐Cyclohexa‐1,3‐Diene) (2‐Tert‐Butyl‐1,1,4,4‐Tetrafluoro‐1,4‐Disilabutene) Metal Carbonyls. MFe, W
Authors: Hseu Tzong‐Hsiung , Lin Cheng‐Hsien , Lee Chi‐Young , Liu Chao‐Shiuan 
Published: June 2015

AbstractMolecular structures of the two title compounds were investigated to reveal the relationship between the structure of the reaction intermediates and the reaction pathways in the transition metal‐mediated cycloaddition reaction between tetrafluorodisilacyclobutene and conjugated dienes. The structures were determined by X‐ray diffraction. Both cyrstals are orthorhombic. Compound I. C14H18O2Si2F4Fe. is of space group P212121 with Z=4; a=6.862(7) Å. b=10.9560(10) Å. c=23.597(25) Å. and Dc=1.562 gcm−1. Compound II, C15H18O3Si2F4W, is of space group Pbca with Z=8; a=16.999(8) Å, b=15.948(6), c=14.045(7) Å, and Dc=1.962 gcm−1. Both structures were solved by heavy‐atom methods and refined by full‐matrix least‐squares using anisotropic temperature factors for all non‐hydrogen atoms to R values of 0.092 for 1544 observed reflections and 0.078 for 2751 observed reflections, respectively, for compound I and compound II. The butadiene segment of the cyclohexadiene ligand is essentially planar in compound I while it is twisted with a torsional angle of 22° (2) in compound II. The five‐membered disilametallacycle ring is planar in compound II while ii is in an envelope comformation in compound I. The coordination geometry of the iron atom may be considered as a distorted tetragonal‐pyramidal with the diene unit occupying the apical site, That of tungsten is a distorted seven‐coordinated pentagonal‐bipyramidal with the two axial carbonyl groups displaced toward the disilabutene ligand. The disilabutene of compound I lies almost parallel and cis to the plane of the butadiene segment while that of compound II orients almost perpendicular to the diene group. The differences in the structural features of the two complexes explain clearly their product patterns and the reactions are apparently stereo‐controlled.