bluuebunny/crossref_metadata_2025 huggingface dataset:
The Structure of Bis[N‐6‐aminopyridyl‐N‐(1S)‐(+)‐10‐camphorsulfonylamino]palladium in the Solid State and in Solution
Authors: Chen Tsun‐Ren , Wu Ying‐Yann , Chen Jhy‐Der , Wang Ju‐Chun
Published: May 2015

The complex, bis[N‐6‐aminopyridyl‐N‐(1S)‐(+)‐10‐camphorsulfonylamino]palladium, Pd[(S)‐APCS]2, 1, was prepared by reaction of 2‐[(1S)‐(+)‐10‐camphorsulfonamino]‐6‐aminopyridine with PdCl2 in THF. Complex 1 has been characterized by spectroscopic methods and its structure has been determined by X‐ray crystallography. Crystal data: space group C2, a= 16.082 (2), b = 17.104 (2), c = 13.051 (2)Å, β = 99.95 (1)°, V = 3535.9 (8) Å3, Z = 2 with final residuals R1 = 0.0491 and wR2 = 0.0944. Two independent molecules, (S,S)‐Pd[(S)‐APCS]2, 1a, and (R,R)‐Pd[(S)‐APCS]2, 1b, were found in each asymmetric unit, which exchange to each other via a series of nitrogen inversion and C‐C bond rotation. The inversion energy (ΔGc1≠) and the energy barrier (δGc2≠) were 11.5 ± 0.1 Kcal mol−1 at 246 K and 9.8 ± 0.1 Kcal mol−1 at 199 K, respectively, calculated by dynamic NMR data.
Ortho‐Alkylation of Phenol with Methanol Using Pb‐Cr Promoted Magnesium Oxide Catalysts
Authors: Ke Jyh‐Harng , Zen Jyh‐Myng , Wang Fey‐Long
Published: May 2015

In this study, Pb‐Cr promoted magnesium oxide catalysts were used to catalyze the ortho‐alkylation of phenol in the presence of excess methanol. The Cr/MgO catalyst exhibited a high conversion of phenol and a relatively high selectivity for the ortho‐alkylation of phenol. The catalytic activity and the stability of Cr/MgO were improved by the addition of a fairly small amount of Pb. The Pb‐Cr/MgO catalyst showed specificity for the ortho‐alkylation of phenol, which was proved by a series of phenol derivative reactions with methanol.
The Synthesis and the X‐Ray Structure of 1,4‐Bis(2‐{4‐[2‐(4‐methylthiophenyl)ethynyl]phenyl}ethynyl)‐2,5‐dihexyloxybenzene
Authors: Xue Cuihua , Luo Fen‐Tair
Published: May 2015

The synthesis and the single crystal structure of the title compound (I), C52H50O2S2, consisting of five benzene rings and four carbon‐carbon triple bonds and with methylthio groups at both ends were described. The distance, according to the X‐ray data, between the two ended sulfur atoms of compound (I) was close to the calculated value from Spartan'04//Hartree‐Fock//3–21G(*). The dihedral angle between the adjacent two benzene rings in this linear conjugated molecule is about 17°.
Flavonoids from the Flowers of Pueraria Lobata
Authors: Ding Hsiou‐Yu , Chen Yi‐Ying , Chang Wen‐Liang , Lin Hang‐Ching
Published: May 2015

A new isoflavonoid glycoside, gehuain, together with three flavonoids and eight isoflavonoids, was isolated from the flowers of Pueraria lobata. Three of them, apigenin, apigenin 4′‐O‐β‐D‐glucoside, and wistin, were reported the first time from this plant. Their structures were established on the basis of spectral evidence.
The Role of Seven‐Membered Ring in the Photoisomerization and Photodissociation of Small Aromatic Molecules
Authors: Tseng Chien‐Ming , Dyakov Yuri A. , Huang Cheng‐Liang , Lee Yuan T. , Lin Sheng‐Hsien , Ni Chi‐Kung
Published: May 2015

Photoisomerization and photodissociation of toluene, xylene, 4‐methyl‐pyridine, and aniline under collision‐free conditions are reviewed. For many years, it was thought that all the isomerization of aromatic molecules could be described in terms of ring permutation. One important characteristic of ring permutation is that the atoms belonging to the alkyl or amino groups attached to the aromatic ring are not involved in the exchange with the atoms within the aromatic ring. Only the relative positions of these alkyl or amino groups are changed. However, the observation of new dissociation products from toluene, xylene, 4‐methyl‐pyridine, and aniline suggests that a small fraction of these molecules undergo another kind of isomerization prior to dissociation. This isomerization involves the exchange between six‐membered ring and seven‐membered ring structures. It provides a new pathway for aromatic molecules to undergo totally different structural change. The significance of this isomerization is that the carbon atoms (or nitrogen atom) and hydrogen atoms belonging to the alkyl group (or amino group) attached to the aromatic ring are involved in an exchange with those atoms in the aromatic ring during the isomerization. The structural change and competition between isomerization and bond dissociation are discussed.
Frequency Scan of a Quadrupole Mass Analyzer in the Third Stability Region for Protein Analysis
Authors: Nie Z. X. , Lin C.‐W. , Peng W.‐P. , Lee Y. T. , Chang H.‐C.
Published: May 2015

A linear quadrupole mass spectrometer operating in the third stability region [(a, q) ≈ (3, 3)] has been developed and utilized to obtain the mass spectra of multiply charged protein ions generated by electro‐spray ionization. The spectra were acquired by scanning the frequency of the quadrupole with a home‐built wide‐band power amplifier from 400 to 100 kHz at constant voltage amplitudes in the range of 100 V. A mass resolution approaching R1/2 = 200 was achieved for doubly charged gramicidin S ions at m/z 570.5. Further improvement of the resolution is anticipated when a higher‐voltage power amplifier is available.
Observation of Nuclear Wavepacket Motion of Reacting Excited States in Solution
Authors: Tahara Tahei , Takeuchi Satoshi , Ishii Kunihiko
Published: May 2015

Three fundamental ultrafast photochemical reactions in solution, i.e., photoisomerization of cis‐stilbene, photodissociation of diphenylcyclopropenone and excited‐state intramolecular proton transfer of 10‐hydroxybenzoquinoline, were studied by two color pump‐probe spectroscopy with time‐resolution as high as 30 −; 70 fs. The coherent nuclear wavepacket motions of the excited‐states that undergo ultrafast reactions were observed, and their relevance to the reaction was discussed. It was concluded that these reactions are classified to three different types for the relation between the initial nuclear wavepacket motion and the reaction coordinate.
Aggregation of Zinc Protoporphyrin in Anodized Aluminum Oxide (AAO) Nanoporous Environments
Authors: Lin Jin‐Shyong , Chen Yu‐Chying , Chen Chien‐Chon , Diau Eric Wei‐Guang , Liu Tzeng‐Feng
Published: May 2015

The aggregation behavior of zinc protoporphyrin (ZnPP) inside nanoporous environments of anodized aluminum oxide (AAO) has been investigated through observation of the variation of UV/visible absorption and emission spectra of the system. The Soret band in the absorption spectrum of ZnPP/AAO thin‐film samples becomes much broader than that observed for ZnPP/THF solutions, and the relative intensity of the Q band is distinctly enhanced for the former. The broad Soret band overlaps the enhanced Q band increasingly as the degree of aggregation increases with increasing duration of immersion, with initial concentration of ZnPP/THF solutions, or with decreasing pore size of AAO nanotubes. A strong excitonic coupling between the Soret and Q transition dipoles causes the absorption spectrum of the ZnPP/AAO system to cover the entire visible spectral region. Emission spectra of ZnPP/AAO samples in the steady state contain multiple resolvable components assigned to monomer, dimer and higher aggregates. The observed systematic variation of emission spectra of ZnPP/AAO samples is consistent with the observation in absorption spectra of the system and reflects the significance of aggregation of ZnPP in a specific nanoporous environment.
Structural Confinement Effects of an Amorphous Magneto‐Semiconductor within Nanochannels
Authors: Chae Weon‐Sik , Choi Kyoung‐Hoon , Kim Yong‐Rok , Jung Jin‐Seung , Malkinski Leszek , O'Connor Charles J.
Published: May 2015

Optical and magnetic properties have been investigated for the structurally confined amorphous magneto‐semiconductor, ternary chalcogenide, within the nanochannels of the mesoporous host. The structural confinement induced a weak crystallographic ordering of the magneto‐semiconductor within the nanochannels. Unique optical properties were observed for this nanocomposite, which were possibly due to the size and energy quantization of the confined guest chalcogenide within the nanochannels. The structural confinement also induced the suppression of the phonon coupling to the photoexcited carriers during the carriers' recombination process. The spin‐glass freezing temperature (Tf = 4.2 K) which was the characteristic magnetic transition temperature for the amorphous bulk was shifted to 2.3 K for the confined system, possibly due to the generation of the superparamagnetic domains induced by the quantum confinement effect.
Spectrophotometric Determination of Dextromethorphan Hydrobromide and Ketamine Hydrochloride in Pure and Dosage Forms
Authors: El‐Sheikh Ragaa , Zaky Monir , Mohamed Faten Zahran , Amin Alaa Sayed , Gouda Ayman Abou El‐Fetouh
Published: May 2015

Three simple, sensitive and accurate spectrophotometric methods have been developed for the determination of dextromethorphan hydrobromide (DEX) and ketamine hydrochloride (KET) in dosage forms. These methods are based on the formation of ion‐pair complexes with bromocresol green (BCG), bromocresol purple (BCP), and bromophenol blue (BPB) in acidic medium. The coloured ion‐pair products are measured at 419, 409 and 417 nm for DEX and at 417, 408 and 416 nm for KET using BCG, BCP and BPB, respectively. Beer's law was obeyed in the range of 2.0–22 μg mL−1 for DEX and 2.0–16 μg mL−1 for KET. The composition of the ion‐pair was established by continuous variation and molar ratio methods. The proposed methods were applied successfully for the determination of DEX and KET in dosage forms applying the standard addition technique and compared statistically with the official methods. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated.
Flow Injection Spectrophotometric Determination of 2,4‐D Herbicide
Authors: Shah Jasmin , Rasul Jan M. , Bashir Nadia
Published: May 2015

2,4‐Dichlorophenoxy acetic acid herbicide is spectrophotometrically determined by diazotization method in a flow injection assembly. The method is based on base hydrolysis of herbicides. The hydrolyzed product 2,4‐dichlorophenol is reacted with diazotized sulfanilic acid. The absorbance of the resulting coloured product was measured at 480 nm. The calibration graph is linear over the range of 0.2–20 μgmL−1, with a relative standard deviation of (RSD) of 7.2% and sample throughput of 90 samples h−1. The % recovery for determination of 2,4‐dichlorophenoxy acetic acid was found to be 92.0–95.3%. The method is easy, simple and faster than the established chromatographic method. The method was applied for determination of 2,4‐dichlorophenoxy acetic acid herbicide in commercial formulations and for residue determination in fruits and food samples.
A Convenient Access to Functionalized Pyrazole, Pyrazolyl‐Azole, and Pyrazolo[3,4‐d]Pyridazine Derivatives
Authors: Dawood Kamal M. , Farag Ahmad M. , Abdel‐Aziz Hatem A.
Published: May 2015

3‐(2‐Furyl)‐3‐oxopropanitrile reacts with keto and ester‐hydrazonyl chlorides to afford the corresponding acetyl‐ and ester‐pyrazole derivatives. The latter pyrazoles reacted with hydrazine and gave either the pyrazolo[3,4‐d]pyridazines or pyrazolylhydrazides. Treatment of the latter hydrazides with phenylisothiocyanate and with phenylisocyanate resulted in the formation of the pyrazolylthiadiazole and pyrazolyloxadiazole derivatives, respectively.
Oxidative Deprotection of Acetals and Trimethylsilylethers by γ‐PCC‐SiO2
Authors: Khodaei Mohammad Mehdi , Salehi Peyman , Yazdanipoor Ateesa , Mirjalili Bibi Fatemeh
Published: May 2015

Acetals, ketals and trimethylsilyl ethers mildly and selectively underwent oxidative deprotection to carbonyl compounds by silica gel supported γ‐picolinium chlorochromate under non‐aqueous conditions in good to excellent yields.
Novel Nucleophilic Substitution Reactions of 5‐Halo‐4‐Sulfur‐Substituted 5,6‐Dihydro‐2‐Pyridones
Authors: Chou Shang‐Shing P. , Hsieh Hsin‐I , Hung Chia‐Cheng
Published: May 2015

The title compounds (3, 8, 9 and 10) were efficiently synthesized, and their substitution reactions with various nucleophiles were carried out. The effects of leaving group, sulfur‐substituent, solvent, reaction temperature, and the nature of the nucleophiles on the reactivity and SN2/SN2′ regioselectivity were studied and rationalized with semi‐empirical calculations.
Carbon‐13 NMR and PM3 Study on the Substituent Effect of 1‐Aryl‐3,3‐Difluoro‐2‐Halocyclopropenes
Authors: Lee Chuan‐Chen , Yang Ya‐Jen , Lin Shaw‐Tao , Chen Li‐Chun
Published: May 2015

The substituent‐induced chemical shifts (SCS) of C2 and C3 on the 13C NMR spectra of 1‐aryl‐3,3‐difluoro‐2‐halocyclopropenes were studied. The correlation between SCS and Hammett constants shows that the tendency of effect by the substituents on the phenyl ring is BrC2(ρ = 4.66) > ClC2(ρ = 4.50) and ClC3(ρ = −1.63) > BrC3(ρ = −1.41). The DSP treatment further confirms the SCS of C2 and C3 are the main contribution of the resonance effect and field effect, respectively. Those results of the incremental shifts reveals that the gem‐difluorocyclopropenyl bearing the phenyl group possesses a triple bond character, which is also observed in IR spectra with high n̈C=C (1768–1945 cm−1).
New Triheterocyclic Ring System. Synthesis of Functionalized Pyrazolo[3,4‐d]Pyrimido[1,2‐b][1,2,4,5]Tetrazine Derivatives
Authors: Mosselhi Mosselhi A. N. , Hussein Ahmad M. , Shawali Ahmad Sami
Published: May 2015

New functionalized pyrazolo[3,4‐d]pyrimido[1,2‐b][1,2,4,5]tetrazine derivatives 6a‐q were synthesized via reaction of the hydrazonoyl halides 1a‐q with 5‐amino‐1‐phenyl‐6‐thioxo‐pyrazolo[3,4‐d]pyrimidin‐4‐one 2 and its 2‐methylthio derivative 3. The mechanism and the regioselectivity of the studied reactions have been discussed.
Novel Synthesis of 1H‐Inden‐1‐Ones and Thienylpropenones in Aqueous Medium
Authors: Hassan Mohamed A. , Batterjee Suzan , Taib Layla A.
Published: May 2015

Condensation of acetylacetone with 4‐methoxybenzaldehyde, 2,4‐dimethoxybenzaldehyde, 3,4‐dimethoxybenzaldehyde, 4‐nitrobenzaldehyde and 2,4‐dinitrobenzaldehyde in water and in the presence of cetyltrimethylammonium bromide (CTABr) as cationic surfactant in dilute sodium hydroxide at room temperature did not afford the expected arylideneacetylacetone but yielded 1H‐inden‐1‐one derivatives 1, while, with piperonaldehyde under the same conditions afforded dipiperonylideneacetone 2. Also 3‐acetylthiophene condensed with some aromatic aldehydes under the same conditions gave the expected stereoselective thienylpropenones 4. The structures of the products were identified by IR, NMR, Mass spectral data and elemental analysis.
Solvent‐Free Preparation of 1,1‐Diacetates from Aldehydes Mediated by Zirconium Hydrogen Sulfate at Room Temperature
Authors: Mirjalili Bibi Fatemeh , Zolfigol Mohammad Ali , Bamoniri Abdolhamid , Sheikhan Nafisehsadat
Published: May 2015

A mild and efficient method has been developed for the preparation of acylals in good yields through a reaction of aldehydes with acetic anhydride using Zr(HSO4)4 as catalyst at room temperature and under solvent‐free conditions.
Ferric Hydrogensulfate Catalysed Schmidt Reaction of Ketones to Amides under Solvent‐Free Conditions
Authors: Eshghi Hossein
Published: May 2015

A new, efficient and convenient method has been developed for the one‐pot synthesis of amides from ketones and sodium azide in the presence of ferric hydrogensulfate in solvent‐free media. Advantages of this method are chemoselectivity, with high yields in a simple operation, and short reaction time under solvent‐free conditions.
Comparative Evaluation of Steam Stability and Catalytic Properties of Four Common Aluminosilicate Mesostructures Prepared by Post‐Grafting Method
Authors: Zhai Shang‐Ru , Wei Li , Qu Feng‐Zuo , Wang Shao‐Jun
Published: May 2015

Four common mesostructured aluminosilicates (e.g. AlMCM‐41, AlMCM‐48, AlMSU‐1 and AlSBA‐15, Si/Al = 7.5) with different pore framework structures were prepared via post‐synthetic method utilizing aluminum isopropoxide as the aluminating agent and characterized by 27Al MAS NMR, XRD, N2‐adsorption isotherm and NH3‐TPD. It was found that, on the basis of the above analysis results, AlMCM‐41, AlMSU‐1 and AlSBA‐15 retained more mesoporosity than cubic Al/MCM‐48 after exposure to pure steam at 800 °C, which may be responsible for their much higher activities in bulky 1,3,5‐triisopropylbenzene (TIPB) conversion.
Kinetic of Patent Blue VF Adsorption from Aqueous Solution on Activated Bone Charcoal
Authors: Bangash Fazlullah Khan , Alam Sultan
Published: May 2015

The effect of temperature of activation on bone charcoal, used as adsorbent for the removal of Patent Blue VF from water solutions was studied. The adsorbent was characterized by FTIR, XRD, SEM and EDS. The kinetic of adsorption of dye was carried out at 10 °C and 45 °C. Carbonization temperature (600–1000 °C) of the adsorbent has significant effect on the removal of dye from water solutions. The first order kinetic, Elovich, Bangham, parabolic diffusion and power function equations were found to fit the kinetic data. Activation energies of adsorption (Δ≠) have higher values for the charcoal activated at high temperatures and the other thermodynamic parameters like ΔH≠, ΔS≠ and ΔG≠ were also found.
Indirect Determination of Captopril with Sodium Nitrate and Thiocyanate by Floatation Separation of Copper
Authors: Wang Chun‐Feng , Guan Xia , Li Quan‐Min , Liu Guo‐Guang
Published: May 2015

A new method for indirect determination of captopril (CPT) with NaNO3 and NH4SCN by floatation and separation of copper has been studied. In the weak acid, a small amount of Cu(II) can be reduced to Cu(I) by CPT, then Cu(I) reacted with the SCN, which can float on the surface of the liquid phase with NaNO3. A good linear relationship is observed between the floatation yield (E%) of Cu(II) and the amount of captopril. The linear range is 2˜32 mg/L. On the ground, captopril can be indirectly determined by determining E(%) of Cu(II). The method is simple, rapid, reliable and has good selectivity. The developed method can be applied to indirect determination of captopril with satisfactory results.
Chemical Composition and Reaction Mechanisms for Secondary Organic Aerosol from Photooxidation of Toluene
Authors: Huang Ming‐Qiang , Zhang Wei‐Jun , Hao Li‐Qing , Wang Zhen‐Ya , Zhou Liu‐Zhu , Gu Xue‐Jun , Fang Li
Published: May 2015

A laboratory study was carried out to investigate the secondary organic aerosol (SOA) products from photooxidation of the aromatic hydrocarbon toluene. The experiments were conducted by irradiating toluene/CH3ONO/NO/air mixtures in a home‐made smog chamber. The aerosol time‐of‐flight mass spectrometer (ATOFMS) was used to measure the size and the chemical composition of individual secondary organic aerosol particles in real‐time. According to a large number of single aerosol diameters and mass spectra, we obtained the size distribution and chemical composition of SOA statistically. Expeperimental results showed that aerosol created by toluene photooxidation is predominantly in the form of fine particles, which have diameters less than 2.5 μm (i.e. PM2.5), and the predominant components of aerosol are furane, methyl glyoxylic acid, phenol, benzaldehyde, benzyl alcohol, cresol, 3‐hydroxy‐2,4‐dioxo‐pentanal, methyl nitrophenol, and 5‐hydroxy‐4,6‐dioxo‐2‐heptenal. The possible reaction mechanisms leading to these products were also discussed.
Aluminum Alkyl Complexes Containing Bidentate, Mono‐ or di‐anionic Pyrrolyl Ligands: Intramolecular Elimination of Methane and 1‐Hexene Polymerization
Authors: Zhou Chong‐Chin , Hung Chen‐Hsiung , Huang Jui‐Hsien , Lee Ting‐Yu
Published: May 2015

A series of aluminum alkyl complexes were synthesized and their catalytic polymerization reactivity toward 1‐hexene was studied. Aluminum complexes, [C4H3N(CH2NHMe)‐2]AlR2 (1a, R = Me; 1b, R = Et), containing substituted pyrrolyl ligand can be prepared by reacting AlR3 with one equiv of C4H3NH(CH2NHMe)‐2 in diethyl ether at room temperature. Dimeric aluminum complexes, {[C4H3N‐(CH2NMe)‐2]AlR}2 (2a, R = Me; 2b, R = Et), can be obtained via metathesis by heating AlR3 and with one equiv of [C4H3NH(CH2NHMe)‐2] in toluene for 24 h or via intramolecular methane elimination by heating 1 and 2 at 90 °C in toluene. Complexes 1a, 1b, 2a, and 2b have been characterized by NMR spectroscopy and by X‐ray crystallography. Complexes 1a and 2a have shown moderate reactivity for 1‐hexene polymerization in the presence of MAO.
Cysteine‐Specific Blue Fluorescence Probe
Authors: Reddy Gondi Sudershan , Chen Hsuan‐Ying , Chang I‐Jy
Published: May 2015

A strong fluorescence probe has been designed to investigate cytochrome c folding kinetics. The cysteine specific modifier, 2‐[(‐Iodo‐acetyl)‐methyl‐amino]‐6‐methylaminobenzoic acidmethyl ester (1), has been prepared, and the reaction with cysteine can be performed in aqueous solution to ensure its application to protein modification. The model compound, 2‐{[2‐(2‐Acetylamino‐2‐methyoxycarbonyl‐ethylsulfanyl)‐acetyl]‐methyl‐amino}‐6‐methyl amino‐benzoic acid methyl ester (2), resulting from the reaction of 1 with N‐acetyl cysteine has emission quantum yields of 0.627 and 0.185 in nonaqueous and aqueous buffer solutions, respectively. The lifetime of 4.6 ns for compound 2 manifests a singlet excited‐state. The Förster energy transfer distance of compound 2 and cytochrome c is calculated to be 45 Å.
New Copper(I) Complex with Triazole Derivative Ligand Containing α‐Diimine Moiety: Synthesis, Structure, Luminescence and Electrochemistry
Authors: Wang Wen‐Jwu , Lin Chien‐Ho
Published: May 2015

One cuprous complex [Cu(L)(PPh3)I] was obtained by reaction of [Cu(PPh3)3I] (PPh3 = triphenyl‐phosphine) with a new α‐diimine ligand L (N‐diphenylmethylene‐3,5‐di(2 ‐pyridyl)‐4‐amino‐1,2,4‐triazole). The complex has been characterized by UV‐Vis, luminescence, 1H NMR spectroscopy and cyclic voltammetric study. The structure of ligand L and complex are confirmed by single crystal X‐ray diffraction study. The compound [Cu(L)(PPh3)I] crystallizes in the monoclinic P21/c space group with a = 19.9291(4), b = 10.0691(2), c = 21.9245(5), α = γ = 90, β = 92.481(10), and Z = 4. The complex shows a MLCT band in the 350˜545 nm region and exhibits luminescent emission at 600 nm at room temperature in dichloromethane solution. Cyclic voltammogram of [Cu(L)(PPh3)I] shows a quasi‐reversible redox couple of the copper center at 0.67 V for Cu(I)/Cu(II) and an irreversible reduction potential at −0.98 V accompanied by a stripping peak of copper at‐0.11 V for Cu(I)/Cu(0).
Hexaamide Molecule Annexed with Pyrenes for Selective Detection of Phosphate and Pyrophosphate Ions by Ratiometric Fluorescence Changes
Authors: Liao Jen‐Hai , Chen Chao‐Tsen , Fang Jim‐Min
Published: May 2015

N,N′‐bis{3,5‐di[(1‐pyrenylmethyl)carbamoyl]benzyl}pyridine‐2,6‐dicarbamide (compound 1) provides a pseudo‐tetrahedron cleft and multiple hydrogen bondings to form a 1:1 complex with phosphate (or pyrophosphate) ion in a highly selective manner, in comparison with other anions (F−, Cl−, Br−, SCN−, AcO−, NO3−, and ClO4−). Compound 1 bears four pyrene rings as the sensitive fluorescent readout unit for phosphate and pyrophosphate ions. The binding strength can be inferred from the emission intensity ratio of the pyrene monomer (λmax = 377 nm) to the excimer (λmax ˜ 480 nm). The enhanced multiple hydrogen bondings and ratiometric sensing mechanism render an opportunity for sensing pyrophosphate ion at micromolar concentration, even in water‐containing solution. The binding model is supported by fluorescence and 1H NMR studies.
Photophysics and Homoconjugation Effect of the Acid‐base Complex between 2,4,6‐Trimethoxy‐2‐styrylquinoline and Protic Acids
Authors: Wang Li‐Ya , Wu Chieh‐Ao , Chen Yong‐Fu , Wang Shun‐Li
Published: May 2015

The influence of hydrogen bonding and protonation on an intra‐molecular charge transfer (ICT) compound, 2,4,6‐trimethoxy‐2‐styrylquinoline (2‐StQ‐2,4,6–30Me), was investigated in the ground state and the excited state. The acid concentration strongly influences the acid‐base reaction between 2‐StQ‐2,4,6–30Me and trifluoroacetic acid (TFA) in a non‐polar solvent. The homoconjugation effect (HE) induced by the presence of an acid was quantified by the red shift of absorption maxima. In strong protic acids, the HE was not observed. For non‐polar to moderate polar solvents, the HE value increases as solvent polarity increases. When the solvent dielectric constant was higher than that of TFA, the HE value is reduced when the solvent polarity increases.
Spin Transition of [Fe(btr)3](ClO4)2 Studied by X‐ray Absorption Spectroscopy
Authors: Lin Yen‐Chen , Hsu I‐Jui , Hsieh Hui‐Huang , Lee Jyh‐Fu , Chen Jin‐Ming , Lee Jenn‐Min , Wang Yu
Published: May 2015

Complex [Fe(btr)3](ClO4)2 (where btr = 4,4′‐bis‐1,2,4‐triazole) exhibits an unusual two‐step spin transition at 188 K and 225 K, respectively. The corresponding three‐dimensional framework structure at each step was characterized by X‐ray diffraction. X‐ray absorption spectroscopy (XAS) at both the Fe K‐edge and the Fe L‐edge is performed to probe the exact electronic configuration at various temperatures. The two‐step behavior observed in the magnetic measurement is well reproduced by XAS. Two types of spin transitions: one abrupt and the other gradual are also observed precisely. The proper technique on monitoring the spin transition by taking advantage of synchrotron radiation is therefore established.
Synthesis of A New Compound: Octaiodo‐9,10‐Anthraquinone
Authors: Jianga Hui‐Ming , Jin Rong‐Chao
Published: May 2015

A new compound: octaiodoanthraquinone (9,10) was synthesized from anthracene by a periodination process under the catalysis of mercury ions at 200˜250 °C. This new compound was also synthesized from anthraquinone (9,10) via a similar process, which verified the mercury‐catalyzed mechanism involved in the synthesis of octaiodoanthraquinone (9,10) from anthracene.
Phenyliodine(III) Bis(Trifluoroacetate) Mediated Synthesis of 2‐Aryl‐1,2‐Benzisothiazol‐3(2H)‐Ones in Ionic Liquid
Authors: Wang Huey‐Min , Liang I‐Chian , Hou Rei‐Sheu , Huang Hsin‐Yu , Chen Ling‐Ching
Published: May 2015

Treatment of N‐aryl‐2‐(benzylthio)benzamides with phenyliodine(III) bis(trifluoroacetate) containing trifluoroacetic acid resulted in an interrupted Pummerer‐type reaction in ionic liquid 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate, [bmim][PF6] to give 2‐aryl‐1,2‐benzisothiazol‐3(2H)‐ones rather than the normal Pummerer‐type products.
Review of the Sampling and Pretreatment Methods for Dioxins Determination in Solids, Liquids and Gases
Authors: Oleszek‐Kudlak Sylwia , Shibata Etsuro , Nakamura Takashi , Li Xian‐Wei , Yu Yong‐Mei , Dong Xiao‐Dan
Published: May 2015

The analytical requirements for the determination of dioxins (e.g. PCDD, PCDF) are unique in comparison with those for other routinely monitored chemicals: dioxins are measured in parts per trillion (ppt) and lower levels in technical and environmental samples, whereas other organics are measured in parts per million (ppm) or parts per billion (ppb). The ultra‐trace analysis of dioxins requires a high sample enrichment obtainable by the use of efficient extraction methods and highly selective purification/fractionation techniques. Furthermore, highly sensitive equipment (e.g. high resolution gas chromatography ‐ HRGC) with detection levels in the ppt range must be used to isolate and separate a huge number of dioxin congeners. The quantification of the dioxins by a high resolution mass detector (HRMS) requires the use of internal and labeled standards.

This paper reviews and compares the classic and modern pretreatment methods, namely extraction and clean‐up, that are currently used in dioxin analysis in industrial samples and that were improved or developed in the last 25 years. In addition, the standard methods for dioxin sampling from an emission source (flue or stack gas) are examined and compared with new, automated techniques.
Sodium Tetrafluoroborate as a New and Highly Efficient Catalyst for One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐Ones and Thiones
Authors: Bandgar B. P. , Kamble V. T. , Bavikar S. N. , Dhavane Abasaheb
Published: May 2015

Sodium tetrafluoroborate (NaBF4) is found to catalyze the three component condensation of an aldehyde, 1,3‐dicarbonyl compound and urea or thiourea to afford the corresponding 3,4‐dihydropyrimidin‐2(1 H)‐ones and thiones in high yields. This method is very useful for the synthesis of a wide range of 3,4‐dihydropyrimidin‐2(1 H)‐ones and thiones from aromatic, heterocyclic, α,β‐unsaturated aldehydes and aliphatic aldehydes.
Iodine‐Catalyzed Friedlander Quinoline Synthesis under Solvent‐Free Conditions
Authors: Zolfigol Mohammad Ali , Salehi Peyman , Ghaderi Arash , Shiri Morteza
Published: May 2015

Polyfunctional quinolines were synthesized using Friedlander method catalyzed by molecular iodine in high yields at 60 °C under solvent‐free conditions.
The Non‐Isothermal Decomposition Kinetics of NaNTO·H2O and the Relationship between its Structure and Properties
Authors: Xu Kang‐Zhen , Ma Hai‐Xia , Song Ji‐Rong , Huang Jie , Ren Ying‐Hui , Hu Rong‐Zu
Published: May 2015

NaNTO·H2O was prepared by mixing 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) aqueous solution and sodium hydroxide aqueous solution. Its thermal decomposition and kinetics were studied under non‐isothermal conditions by DSC and TG/DTG methods. The kinetic parameters were obtained from analysis of the DSC and TG/DTG curves by the Kissinger method, the Ozawa method, the differential method and the integral method. The most probable mechanism function for the thermal decomposition of the first stage was suggested by comparing the kinetic parameters. The critical temperature of thermal explosion (Tb) was 240.93 °C. The theoretical investigation on the structure unit of the title compound was carried out by DFT‐B3LYP/CEP‐31G methods; atomic net charges and the population analysis were discussed.
Self‐Consistent Variational Transition State Theory with Multidimensional Tunneling Calculations in an Embarrassingly Parallel Scheme
Authors: Chou Chien‐Pin , Chuang Yao‐Yuan
Published: May 2015

Variational Transition State Theory with Multidimensional Tunneling (VTST/MT) has been successfully used for calculating rate constants of reactions in gas and condensed phases. The current software implementation of VTST/MT is, however, based on the assumption of a fast, serial evaluation of the energetic information of a given molecular structure. We propose a simple and effective parallel method for performing VTST/MT calculations utilizing a cost effective Linux based PC cluster. Five different parallel computing schemes for choosing structures and computing their Hessians along a pre‐defined Minimum Energy Path were developed. We found that the Energy Block and Asymmetric Cyclic Execution (EBACE) scheme, which is also most physically intuitive, results in converged rate constants with the least number of Hessians computed. We believe that carrying out the VTST/MT calculation in parallel makes it more attractive for calculating the rate constants of complex chemical systems.
Purification and Characterization of Three Galactose Specific Lectins from Sajna (Moringa Oleifera L.) Leaves
Authors: Khatun Shahanaz , Ashraduzzman M. , Absar N. , Pervin F. , Abbas Ali M. , Bari Luthfunnesa , Karim M. R. , Hassan Parvez
Published: May 2015

Three lectins designated as SLL‐1, SLL‐2 and SLL‐3 were purified from small sized Sajna (Moringa oleifera L.) leaves by gel filtration of 100% ammonium sulfate saturated crude protein extract on Sephadex G‐75 followed by ion‐exchange chromatography on DEAE and affinity chromatography on Sepharose‐4B. The molecular weight of the lectins SLL‐1, SLL‐2 and SLL‐3 were 1,55,000, 1,15,000 and 85,000, respectively, as determined by gel filtration on Sephadex G‐150 and 1,60,000; 1,20,000 and 85,500, respectively, by SDS‐polyacrylamide slab gel electrophoresis. SLL‐1 and SLL‐2 are dimer in nature held together by disulfide bond (s), while SLL‐3 is a monomer. The lectins agglutinated specifically rat red blood cells and the agglutination was inhibited specifically by methyl‐α‐D‐galactopyranoside, methyl‐β‐D‐galactopyranoside and D‐galactose. The lectins SLL‐1, SLL‐2 and SLL‐3 contain 3.9, 3.4 and 2.8% neutral sugar, respectively, and the sugar compositions were glucose for SLL‐1, mannose for SLL‐2 and SLL‐3 contained either N‐acetyl‐D‐glucosamine or N‐acetyl‐D‐galactosamine or both. The lectins exhibited cytotoxicity in brine shrimp lethality bioassay.
Simultaneous Spectrophotometric Determination of Iron and Cobalt in Micellar Medium by Using a Principal Component Artificial Neural Network and Multivariate Calibration
Authors: Nekoei Mehdi , Mohammadhosseini Majid
Published: May 2015

A simple and reliable method for simultaneous spectrophotometric determination of iron(II) and cobalt(II) has been established. The method is based on complex formation with 1‐(2‐pyridylazo)‐2‐naphtol (PAN) in a micellar medium. Despite a spectral overlap, Fe2+and Co2+have been simultaneously determined with chemometric approaches involving principal component artificial neural network (PC‐ANN), principal component regression (PCR) and partial least squares (PLS). Various synthetic mixtures of iron and cobalt were assessed and the results obtained by the applications of these chemometric approaches were evaluated and compared. It was found that the PC‐ANN method afforded relatively better precision than that of PCR or PLS. The proposed method permits detection limits of 0.05 and 0.07 ng mL−1for Co and Fe, respectively. The influences of pH, ligand amount, solvent percentage and time on the absorbance were also investigated. The proposed method was also applied satisfactorily for the determination of Fe(II) and Co(II) in real and synthetic samples.
Elucidating Factors Manipulated the Formation of Multiply Charged Protein Homomultimeric Complexes by Electrospray Ionization
Authors: Ho Yeung‐Haw , Chen Jin‐Wen , Hu Tsai‐Lin
Published: May 2015

Native non‐covalently bonded protein‐protein and protein‐substrate complexes are of great interest and have been extensively studied by electrospray ionization mass spectrometry (ESI‐MS). Multiply charged protein homomultimeric complexes are shown to form by ESI‐MS. This study addresses factors that can artificially induce the formation of multiply charged protein homomultimeric complexes. Cytochrome c (Cyt c) and ubiquitin, which are monomers in solution, were found to generate (Cyt c)mn+ by electrospray ionization (ESI). The homomultimeric complexes were not limited to dimeric complexes but include also multiply charged trimers, tetramers, and pentamers. The observation of these homomultimeric complexes has never been revealed from a Cyt c solution at the concentration as low as 10 μM. Increasing the concentration of Cyt c enhanced the formation of (Cyt c)mn+ as expected; however, the protein concentration does not affect the relative intensities of monomeric and dimeric complexes. Additionally the enrichment of NH4OH also promotes the formation of (Cyt c)mn+. Notably, source collision‐induced dissociations (source‐CID) of (Cyt c)mn+ alter the charge state distribution (CSD) and may lead to an incorrect interpretation of Cyt c conformations. Hence, extra care should be taken when using CSD to interpret the conformation of a protein derived from ESI‐MS.
Interaction of β‐Cyclodextrin with Cetyltrimethylammonium Bromide in the Presence of Neutral Red and Its Application to the Spectrophotometric Determination of β‐Cyclodextrin
Authors: Afkhami Abbas , Khalafi Lida
Published: May 2015

The effects of addition of β‐cyclodextrin (β‐CD) to the neutral red‐cetyltrimethylammonium bromide (CTAB) associates in pH 7 phosphate buffer solutions were investigated. Addition of β‐CD to neutral red‐CTAB association causes decomposition of the associate by displacement of neutral red with β‐CD. The inclusion complex of CTAB with β‐CD is more stable than that with neutral red. The results indicate that formation of inclusion complex of CTAB with β‐CD prevents its association with neutral red, and inclusion complex formation of β‐CD and neutral red in the presence of CTAB takes place after total consumption of CTAB. The competition of β‐CD and neutral red on the interaction with CTAB can be used for the simple, rapid and sensitive spectrophotometric determination of β‐CD.
Synthesis and Antimicrobial Activity of Some Annelated Quinazoline Derivatives
Authors: Aly A. A.
Published: May 2015

A highly efficient and versatile synthetic approach to the synthesis of annelated quinazoline derivatives viz 1,2,4‐triazino[4,3‐c]quinazoline 5–7, 11, thiazolidinylquinazoline 9, quinazolino[4,3‐b]quin‐azolin‐8‐one 12 and imidazoquinazolines 14a,b,15 is presented. Also, a variety of pyrazolylquinazolines 19–21 and pyrimidinylquinazolines 22a,b were obtained via a sequence of heterocyclization reactions of 4‐methyl‐N‐[4‐(4‐oxo‐3,4‐dihydroquinazolin‐2‐yl)phenyl]benzene‐sulfonamide (2) with different reagents. The new compounds were synthesized with the objective of studying their antimicrobial activity.
Reactivity of Arenesulfinic Acids as Nucleophiles in the Addition Reaction to 2‐Haloacrylonitriles
Authors: Zvezdova D. , Stoeva S. , Aleksiev D.
Published: May 2015

The nucleophilic addition reactions of both the non‐substituted and p‐substituted benzenesulfinic acids with 2‐chloro‐ and 2‐bromoacrylonitriles have been studied. The structures of the 3‐benzenesulfonyl‐2‐halogenopropanenitriles thus obtained were confirmed by microanalytical and spectral methods. The basic kinetic parameters of the reactions were determined and some local electronic descriptors concerning the reaction centers were calculated. For the interaction with benzenesulfinic acids, 2‐bromoacrylonitrile was found to have higher reactivity as a Michael acceptor than 2‐chloroacrylonitrile. The higher reactivity of 2‐bromoacrylonitrile is associated with the higher electrophilicity of its β‐carbon atom, which was proved by its pronounced acceptor delocalizability and increased reaction rate values with the corresponding benzenesulfinic acids.
Efficient Oxidation of Alcohols to Carbonyl Compounds by N,N‐Dichloro‐4‐Methylbenzenesulfonamide under Mild Conditions
Authors: Khazaei Ardeshir , Raiatzadeh Ayeh , Rostami Amin
Published: May 2015

A number of aldehydes and ketones were prepared by oxidation of alcohol by N,N‐dichloro‐4‐methylbenzenesulfonamide under mild and neutral conditions in good to high yield in dichloromethane at room temperature.
Synthesis and Antimicrobial Activity of Novel Quinoxaline Derivatives
Authors: Badran Mohga M. , Moneer Ashraf A. , Refaat Hanan M. , El‐Malah Afaf A.
Published: May 2015

In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones (2a‐d) and their 2‐chloro (3a‐d) and 2‐piperazinyl derivatives (4a‐g) were synthesized from 3‐methylquinoxalin‐2(1H)‐one (1). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones (5a‐d) was also prepared. Moreover, 3‐(N2‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones (8a‐c) as well as their cyclized oxadiazolinyl derivatives (9a‐c) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones (11a‐c) and (12a‐c) were obtained from the intermediate compound (10) ‐ previously obtained via cyclization of (7) with CS2. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one (13), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one (14) and its 2‐chloro derivative (15) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one (7). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.
Microwave Assisted Amine Formylation by a Heterogeneous HCO2H/SiO2 System
Authors: Khoramabadi‐Zad Ahmad , Veisi Hojat , Akbari Safar‐Ali , Shiri Azam
Published: May 2015

A simple, fast and efficient procedure has been developed for the synthesis of formamides by treating a silica gel/formic acid mixture with amines under microwave irradiation.
Design, Synthesis and Biological Evaluations of a Novel Series of Enediynes Constituted with DNA Cleavage, Alkylating and DNA Binding Agents via Varies Spacers
Authors: Lin Chi‐Fong , Hwang Martin , Kuo Yao‐Haur , Wu Ming‐Jung
Published: May 2015

Among the three series of complicated combinatory enediynes, 3a˜d were more active than 2a˜c and 4a˜b, in which 3a˜b showed equally inhibitory activity against the growth of Hepa59T/VGH, KB and Hela with mean IC50 values lower than 10 μg/mL. Compounds 2a and 3b exhibited the most potent inhibitory activity against the growth of Hela cells for 4.39 μg/mL. Derivative 3d displayed the greatest ability against the growth of Hepa59T/VGH cell lines for 6.95 μg/mL, while 3a showed more cytotoxic to KB cells than other analogs. Conjugates 2a‐c presented better responses than 3a‐d for the DNA cleavage assay of supercoiled ΦX174.
Biotinylation of Peptides/Proteins Using Biocytin Hydrazide
Authors: Lee Bao‐Shiang , Krishnanchettiar Sangeeth , Lateef Syed Salman , Gupta Shalini
Published: May 2015

Biocytin hydrazide is widely used to biotinylate the carbohydrate moieties of glycoproteins. In this study, however, biocytin hydrazide was found to be able to directly biotinylate peptides and proteins. This phenomenon may cause false identification of non‐glycopeptides/non‐glycoproteins as glycopeptides/glycoproteins. Here, we report a systematic investigation of the reaction of peptides/proteins with biocytin hydrazide. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry is used to analyze the biotinylation reaction between peptides/proteins and biocytin hydrazide. Peptides/proteins were reacted with biocytin hydrazide in diverse solvent systems with different biocytin hydrazide concentrations for up to 96 h at temperatures ranging from 4 °C to 65 °C. Singly biotinylated or multiply biotinylated peptides/proteins are observed. The efficiency of the biotinylation reaction increases with higher temperature, higher biocytin hydrazide concentration, or longer reaction time. The influence of buffer pH on the biotinylation reaction of peptides/proteins is less pronounced. The biotinylation efficiency is optimum at neutral pH. Data suggests that the peptides are biotinylated as efficiently as proteins. The observation that peptides/proteins condense only with biocytin hydrazide, 2‐iminobiotin hydrazide, adipic dihydrazide and phenyl hydrazine but not with biocytin HCl and 2‐iminobiotin, indicates that the biotinylation reaction of peptides/proteins occurs with the hydrazide moiety but not with biotin moiety of the biotinylated reagent. The postsource decay data of biotinylated P14R indicates that biocytin hydrazide condenses with the guanidino group of arginine's side chain of P14R, indicating that besides N‐terminal and lysine residue of peptides/proteins, arginine residue is capable of reacting with biocytin hydrazide.
Nonisothermal Kinetics of Sub‐Solidus Phase Transitions in C10Zn, C16Zn and Their Binary System
Authors: Wu Ke‐Zhong , Liu Xiao‐Di , Li Jian‐Ling
Published: May 2015

Nonisothermal kinetics of the solid‐solid phase transition in (n‐C10H21NH3)2ZnCl4(C10Zn), (n‐C16H33NH3)2ZnCl4(C16Zn) and their binary system were determined by Kissinger and Ozawa methods from DSC measurements. The activation energy Ea of the binary system shows a waving dependence on WC10Zn%, which is caused by not only an intermediate (C10H21NH3)(n‐C16H33NH3)ZnCl4 but also three solid solution ranges (α, β, γ) in the phase diagram of C10Zn‐C16Zn. The variations of the layer d‐spacing are also convenient for the above result.
Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene
Authors: Lin Kun‐I , Chiang Li‐Wu , Wu Chien‐Hung , Chen Shao‐Wei , Yu Chung‐Shan
Published: May 2015

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[125I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.
KHSO4 Supported Onto Bentonite, A Versatile Reagent for Aromatization of Hantzsch 1,4‐Dihydropyridines
Authors: Heravi Majid M. , Bakhtiari Khadijeh , Oskooie Hossein A.
Published: May 2015

Aromatization of Hantzsch 1,4‐dihydropyridines was promoted by KHSO4, a relatively green chemical, supported onto bentonite to yield the corresponding pyridine derivatives in excellent yields. The reaction was carried out under mild and convenient conditions.
Interactions of Phenylalanine, Tyrosine and Histidine in Aqueous Caffeine Solutions at Different Temperatures
Authors: Ali A. , Sabir S. , Nain A. K. , Hyder S. , Ahmad S. , Tariq M. , Patel R.
Published: May 2015

Densities, ρ, viscosities, η, and refractive indices, nD of aqueous caffeine (0.5 M) and of solutions of amino acids, l‐phenylalanine (Phe), l‐tyrosine (Tyr) and l‐histidine (His), (0.01–0.05 M) in aqueous‐caffeine have been measured at 298.15, 303.15, 308.15 and 313.15 K. From these experimental data, apparent molar volume, ϕv, limiting partial molar volume, ϕºν and the slope, Sv, transfer volume, ϕºν,tr, Falkenhagen coefficient, A, Jones‐Dole coefficients, B, free energies of activation per mole of solvent, Δμo#1 and per mole of solute, Δμo#2, enthalpy, ΔH* and entropy, ΔS* of activation of viscous flow, and molar refraction, Rm were calculated. The results are interpreted from the point of view of solute‐solvent and solute‐solute interactions in these systems. It has been observed that there exist strong solute‐solvent and weak solute‐solute interactions in these systems. Further, the solute‐solvent interactions decrease, whereas solute‐solute interactions increase with rise in temperature. It is observed that these amino acids act as structure‐makers in aqueous‐caffeine solvent. The thermodynamics of viscous flow have also been discussed.
Thermodynamic Studies on Amino Acid Solvation in Aqueous Urea
Authors: Chatterjee Someswar , Basumallick I.
Published: May 2015

The present paper discusses the behaviour of transfer free energy of some amino acids from water to 4M, 6M and 8M aqueous urea. Dissection of transfer free energy into cavity term, interaction term and electrical term reveals that cavity forming free energy of transfer ΔG0t (cav) plays an important role in dictating actual interaction of amino acids in aqueous urea. Cavity forming free energy of transfer has been estimated by using Scaled Particle Theory (SPT).
Electrode Kinetics and Complex Formation of [Zn‐Antibiotics‐Cephalothin] System vis a vis Kinetics of Electrode Reactions
Authors: Khan Farid
Published: May 2015

Charge transfer reactions between a dropping mercury electrode and a [Mn‐antibiotics‐cephalothin] system were studied at pH = 7.30 ± 0.01, μ = 1.0 MNaClO4 at 298 K. The antibiotics were doxycycline, chlortetracycline, oxytetracycline, tetracycline, minocycline, amoxicillin and chloramphenicol used as primary ligands and cephalothin as secondary ligand formed 1:1:1, 1:1:2 and 1:2:1 complexes with Zn2. Electrode kinetics was discussed on the basis of kinetic parameters viz. transfer coefficient (α), degree of irreversibility (λ), diffusion coefficient (D) and rate constant (k). The values of α varied from 0.40 to 0.57 (0.50) confirm that ‘transition state’ behaves between reactant and product response to applied potential and it lies always between d.m.e. and solution interface. A small variation in potential affects the rate and rate constant greatly.
Easily Accessible 2‐(2‐Bromophenyl)‐4,4,5,5‐Tetramethyl‐[1,3,2]Dioxaborolane for Suzuki‐Miyaura Reactions
Authors: Wang Tein‐Fu , Lin Ching‐Lung , Chen Chih‐Neng , Wang Tan‐Ching
Published: May 2015

A simple and direct method has been developed for the preparation of the title compound from 1,2‐dibromobenzene. Suzuki‐Miyaura reactions of this compound with substituted bromoaryls proceeded smoothly to give 2‐bromobiphenyl derivatives in moderate to excellent yields. Instead of converting each of the bromoaryl compounds to the corresponding arylmetals followed by reacting with 2‐iodobromobenzene, the advantage of this protocol is that the substituted bromoaryls were used directly to couple with the title compound.