bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homogeneous Line‐Width of Optical Transitions and Multiple Electron‐LO‐Phonon Scattering in Quantum Dots
Authors: Král Karel , Khás Zdenk , Lin Chung‐Yi , Lin Sheng‐Hsien 
Published: May 2015

AbstractThe optical line‐shape of electronic transitions due to the polar electron‐LO‐phonon interaction in semiconductor quantum dots is studied. The mechanism of the finite optical line‐width is based on the multiple electron‐LO‐phonon scattering. The influence of the higher order corrections beyond the self‐consistent Hartree‐Fock approximation to the electron‐phonon part of the electronic self‐energy is estimated quantitatively. The problem is studied within the two‐level model of a single electron interacting with the system of longitudinal optical phonons of the whole bulk sample of the polar semiconductor. The influence of the higher order corrections is demonstrated on the line‐shape of the optical transitions, the temperature dependence of the line‐width and on the dependence of the line‐width on the size of the quantum dot.
Excited State Coherent Vibrational Motion in Deoxymyoglobin
Authors: Lambry Jean‐Christophe , Vos Marten H. , Martin Jean‐Louis 
Published: May 2015

AbstractFemtosecond coherence spectroscopy of deoxymyoglobin has been performed under excitation in the lowest electronic transition (Q band) and probing in the Soret band. Under these excitation conditions, ground state low‐frequency vibrational motions are strongly suppressed with respect to Soret excitation. Evidence is presented for a contribution of excited state vibrational dynamics to the coherent response.
Ultrafast Non‐Adiabatic Curve Crossing and Energy Transfer in the IBr B0+·Ar van der Waals Complex
Authors: Hussain Ahmed N. , Roberts Gareth 
Published: May 2015

AbstractPhotodissociation of the T‐shaped IBr B0+·Ar complex initiated by an ultrafast laser pulse is investigated theoretically by integrating the time‐dependent Schrödinger equation for wavepacket motion in two dimensions. The fragmentation dynamics are explored through calculations of time‐dependent expectation values, electronic state populations and vibrational state probabilities. The focus of this study is on the competition between electronic predissociation of IBr, induced by non‐adiabatic transitions between the bound B0+ and repulsive Y0+ excited states, and vibrational predissociation of Ar from the intact diatomic, mediated by vibrational energy redistribution between intramolecular and van der Waals degrees of freedom. This is facilitated by comparative calculations in which non‐adiabatic curve crossing is either included or artificially disabled. It is found that molecular dissociation to form ground‐state I + Br at energies below the B0+ asymptotic limit takes place over time scales ranging from 200‐500 fs for vibrational levels that are strongly coupled to the Y0+ continuum, to longer than 10 ps for the most metastable levels. Sequential loss of vibrational quanta from IBr B0+ into the van der Waals mode over a 2‐10 ps time scale is significantly disturbed by dissociation of the diatomic moiety: instead of time‐ordered vibrational cooling via consecutively lower‐energy levels, a complex pattern of energy transfer evolves during the lifetime of metastable B0+ vibrational levels until the Ar atom is propelled into the van der Waals continuum. The probabilities of final IBr B0+ vibrational levels are determined, therefore, by the strength of non‐adiabatic transfer to the molecular dissociative continuum in addition to the dynamical coupling of intramolecular and van der Waals modes.
Temporal Contrast of High Intensity Femtosecond UV Pulses
Authors: Osvay Károly , Csatári Márta , Gaál Attila , Ross Ian N. 
Published: May 2015

AbstractEstimates of temporal pulse contrast ratio to high values can be obtained from significantly lower dynamic range measurements of the pulse spectrum. The effect of non‐compensated third‐order dispersion of a laser system on the pulse contrast is also calculated.
Morphology‐Dependent Resonances in a Dielectric Microsphere and Femtosecond Laser Pulses
Authors: Sbanski O. , Roman V. E. , Kiefer W. , Popp J. 
Published: May 2015

AbstractMie‐scattering on microspheres is investigated experimentally and theoretically on a femtosecond timescale. Although the pulse duration is smaller than the particle circumference, morphology‐dependent resonances are excited, leading to a distinct pulse shaping and elongation of the scattered light.
Solvent Extraction Separation of Gold with Cyanex 302 as Extractant
Authors: Sarkar Sunil G. , Dhadke Puroshattam M. 
Published: May 2015

AbstractA method has been developed for the extraction of gold(III) from hydrochloric solution with Cyanex 302 dissolved in toluene. The extraction was quantitative from 0.005‐8.0 M HCl with 7.5 × 10−4 M Cyanex 302 and an equilibrium period of 3.0 min. Gold(III) from the non‐aqueous phase was stripped with 0.1 MNa2S2O3 and determined spectrophotometrically at 400 nm using stannous chloride method. The method is useful for separation of Au(III) from Cu(II), Ni(II), Pd(II), Pt(IV)and Fe(III) and was extended for the determination of Au(III) in Ayurvedic drug samples.The method is reproducible with a relative standard deviation of ± 1.0%.
Total Energy Calculations for Silane Dissociative Chemisorption onto Si(100) and Si(111) Surfaces
Authors: Lm Jyh‐Shing , Kuo Yu‐Tzu , Chen Ji‐Cheng , Lee Ming‐Hsien 
Published: May 2015

AbstractTotal energy calculations based on density functional theory in connection with generalized gradient approximation (GGA) and norm‐conserving optimized pseudopotential approximation have been used to investigate the silane chemisorption onto Si(111) and Si(100) surfaces. Firstly, the calculated relaxed surface structure of Si(100)‐(2×2) has a different dangling bonds environment from that of the calculated relaxed surface structure of Si(111)‐(1×1). Secondly, our calculated results indicate that SiH4 chemisorption onto both Si(100)‐(2×2) and Si(111)‐(1×1) surfaces are energetically favorable and they lead to the formation of SiH3 and H adsorbed on the Si=Si dimer, i.e. Si(100)‐(2×2)(SiH3:H) and the surface dihydride SiH2 and 2H, i.e. Si(111)‐(1×1)(SiH2:2H), respectively. Finally, the increase of dangling bond density and the absence of adatom backbond breaking are probably two of the key factors controlling the distinct increase in reaction probability for dissociative chemisorption of SiH4 onto Si(111)‐(7×7) due to Si(111)‐(7×7) ↔ Si(111)‐(1×1) phase transition at surface temperature greater than 800°C.
Reactions of TiCl4 or Ti(O‐i‐Pr)Cl3 with 2,4‐Pentanedione. The Molecular Structures of TiCI3(acac)(THF) and Ti(O‐i‐Pr)CI2(acac)(THF)
Authors: Shao Ming‐Yuan , Ho Yuh‐Chou , Gau Han‐Mou 
Published: May 2015

AbstractA series of titanium(IV) acetylacetonate (acac) complexes, Ti(acac)Cl3 (THF) (2), [Ti(acac)Cl2(THF)]2 (μ‐O) (3), [Ti(O‐i‐Pr)Cl3(acac)]‐(HNEt3+) (5), and Ti(O‐i‐Pr)Cl2 (acac)(THF) (6), were prepared from reactions of TiCl4 or Ti(O‐i‐Pr)Cl3 with 2,4‐pentanedione (Hacac) in CH2Cl2 or THF with or without the presence of NEt3. The x‐ray structural analyses were carried out on complexes 2 and 6. Complex 2 crystallizes in the monoclinic P21/n space group with a = 8.664(1) Å, b = 11.859(1) Å, c = 14.320(1) Å, β = 103.94(1)°, R = 0.0571, Rw = 0.0620, and G of = 1.10. Complex 6 crystallizes also in the monoclinic P21/n space group with a = 9.074(2) Å, b = 11.499(2) Å, c = 16.549(4) Å, β = 101.96(2)°, R = 0.0492, Rw = 0.0671, and Gof= 1.49. Based on the solid state structures of complexes 2 and 6, the relative bonding order of −O‐i‐Pr > Cl− > acac− THF is established.
Electron Impact Mass Spectra of 3‐Aryl‐3‐hydroxyl‐2,2,4,4‐tetramethylcyclobutanones and Related Compounds
Authors: Lin Shaw‐Tao , Lin Wen‐Chung , Chao Richard Yung‐Ho , Huang Ching‐Liang 
Published: May 2015

AbstractThe mass spectra of 3‐aryl‐3‐hydroxyl‐2,2,4,4‐tetramethylcyclobutanones and their related compounds were studied. The arylcyclobutanones and their ketal forms demonstrate similar fragmentation patterns but with different observed common peaks, i.e., [M‐70]+ and 114 amu, as the base peaks for compounds arylcyclobutanones and their ketal forms, respectively. 1‐Aryl‐2,2,4‐trimethyl‐1,3‐pentadiones, obtained from hydrolysis of cyclobutanones, gave either 43 amu or [Ar‐CO]+ as the peaks, depending on the substituents on the benzene ring. These compounds are good examples of how the relative ionization potentials of the possible fragments govern the observed mass spectra.
Heterocyclic Fused Rings with Bridgehead Nitrogen Atoms: Synthesis of [1,2,4]triazolo[1′,5′:4,3][1,4]oxazepino[5,6‐b]pyrazole Derivatives
Authors: Sayed Samia M. 
Published: May 2015

AbstractNovel [1,2,4]triazolo[1′,5′:4,3][1,4]oxazepino[5,6‐b]pyrazole derivatives have been synthesized using pyrazolo‐4‐carboxylic acid 1 as starting material is reported.
Behaviour of Some Activated Nitriles Toward Barbituric, Thiobarbituric Acids and 3‐Methyl‐1‐Phenylpyrazol‐5‐One
Authors: Madkour H. M. F. , Mahmoud M. R. , Nassar M. H. , Habashy M. M. 
Published: May 2015

AbstractThe effect of some active methylene containing heterocyclic compounds, namely barbituric, thiobarbituric acids and 3‐mehtyl‐1‐phenylpyrazol‐5‐one on α‐cyano‐3,4,5‐trimethoxycinnamonitrile and ethyl α‐cyano‐3,4,5‐trimethoxycinnamate 1a,b was investigated. The structure of the new products was substantiated from their IR, 1H NMR and mass spectra.
Novel One‐Pot Synthesis of Pyrazolo[3,4‐b][1,4]oxazines
Authors: Raslan M. A. , El‐Latif F. M. Abd , Otto H. H. , Sadek K. U. 
Published: May 2015

AbstractA simple route for the synthesis of pyrazolo[3,4‐b][1,4]oxazines by the reaction of pyrazole‐4‐oxime derivatives 1 with active methylene reagents has been reported.
Evaluation of the Concentration and Enantiomeric Purity of Selected Free Amino Acids in Chinese Fermented Soy Beans
Authors: Chen Shushi 
Published: May 2015

AbstractThe total concentration and enantiomeric composition of two selected amino acids (leucine, phenylalanine) in eight different Chinese fermented soy beans were determined after their derivatization with N‐benzoyl chloride using HPLC system coupled with UV detector. In comparison, fermented soy beans tended to be relatively higher in both the total concentration and enantiomeric composition than raw soy beans. In most samples, phenylalanine was analyzed to have a higher percentage of D‐enantiomer and lower total concentration than leucine. The level of total concentration for examined amino acids was found irrelevant to the storage conditions (e.g., stored in dry or wet form). However, samples preserved in wet form (i.e., soaked in sauce) were likely to have higher percentage of D‐enantiomers (D‐phenylalanine, D‐leucine). In some cases the relative amounts of D‐phenylalanine and D‐leucine exceeded 20% of the individual amino acids. No significant racemization of N‐benzoyl derivatized amino acids was detected at room temperature. However, the elevation of surrounding temperature caused an increase in the percentage of D‐enantiomers.
Flow Binding Assay Using Sequential Injection Analysis for Bioprocess Monitoring
Authors: Shu H.‐C , Lmg Y.‐C. 
Published: May 2015

AbstractA sequential injection analysis system (SIA) using a small column of immobilized concanavalin A (Con A) reacting with horseradish peroxidase (HRP) as a model system was developed to demonstrate the feasibility of flow binding assay for bioprocess monitoring and control. The selection of liquid drive and immobilized supports is justified. System performance was evaluated on three assay formats: a direct binding assay, competitive binding assay, and sandwich‐binding assay. In direct binding assay, immobilized Con A mounted in the SIA system was used to determine the concentration of HRP. The competitive binding assay using a free carbohydrate, methyl‐D‐mannopyranoside to provide competitive binding situation gives more complex calibration curves and decreased precision at higher concentrations. The sandwich‐binding assay did not work well. Direct binding assay is recommended to be the best choice based on sensitivity and precision viewpoints. The total time for one assay cycle ranges from 5 ∼ 8 min, depending on the conditions. The current SIA system is fully computerized and yields rapid and reliable system performance. The potential of using SIA‐based flow binding assay on the area of bioprocess monitoring is promising.
Continuous Analysis of Urea in Blood by Immobilized Urease Using a Conductive Biosensor
Authors: Shu Hun‐Chi , Wu Ning‐Ping 
Published: May 2015

AbstractUrea in blood from a patient undergoing dialysis was continuously monitored using immobilized urease reactor with a conductivity meter. A linear response of urea in the range between 5 to 50 mM with the throughput of 15 samples h−1 was obtained. Urea measured with this biosensor shows a good correlation with the chemical analysis method. A good operational stability for on‐line monitoring during dialysis and the promising storage stability of the urea reactor were found. At 4, and 25°C, no significant activity loss was detected in the urease reactor throughout the 50 weeks storage time. At 37°C, no activity decline was observed before 20 weeks. However, after 50 weeks storage, no activity in the reactor can be detected.
A New Method for the Preparation of Para‐Substituted Benzohydroxamic Acids
Authors: Dhuru Sameer P. , Salunkhe Manikrao M. 
Published: May 2015

AbstractA new method for the preparation of para‐substituted benzohydroxamic acids from para‐substituted benzoic acids by using hydroxylamine hydrochloride in the presence of triphenyl phosphine and N‐bromosuccinimide under mild basic conditions is described.
Synthesis of Two Derivatives of 3,6,9‐tri(carboxymethyl)‐3,6,9‐triazaundecanedioic Acid and the Stabilities of Their Complexes with Ca2+, Cu2+, Zn2+, Dy3+ and Gd3+
Authors: Wang Yun‐Ming , Cheng Tsann‐Hwang , Liu Gin‐Chung 
Published: May 2015

AbstractTwo N‐2‐hydroxy‐1‐phenylethyl and N‐2‐hydroxy‐2‐phenylethyl derivatives of DTPA (3,6,9‐tri(carboxymethyl)‐3,6,9‐triazaundecanedioic acid), DTPA‐H1P = 3,9‐di(carboxymethyl)‐6‐2‐hydroxy‐1‐phenylethyl‐3,6,9‐triazaundecanedioic acid, and DTPA‐H2P = 3,9‐di(carboxymethyl)‐6‐2‐hydroxy‐2‐phenylethyl‐3,6,9‐triazaundecanedioic acid were synthesized. Their protonation constants were determined by Potentiometric titration in 0.10 M Me4NNO3 and by NMR pH titration at 25.0 ± 0.1°C. The formations of lanthanide(III), copper(II), zinc(II) and calcium(II) complexes were investigated quantitatively by potentiometry. The stability constant for Gd(III) complex is larger than those for Ca(II), Zn(II) and Cu(II) complexes with these two ligands. The selectivity constants and modified selectivity constants of the DTPA‐H1P and DTPA‐H2P for Gd(III) over endogenously available metal ions were calculated. Comparing pM values at physiological pH 7.4 assesses effectiveness of these two ligands in binding divalent and trivalent metal ions in biological media. The observed water proton relaxivity values of [Gd(DTPA‐H1P)]− and [Gd(DTPA‐H2P)]− became constant with respect to pH changes over the range of 4‐10. 17O NMR shifts showed that the [Dy(DTPA‐H1P)]− and [Dy(DTPA‐H2P)]− complexes at pH 6.30 had 1.91 and 2.28 inner‐sphere water molecules, respectively. Water proton spin‐lattice relaxation rates of [Gd(DTPA‐H1P)]− and [Gd(DTPA‐H2P)]− complexes were also consistent with the inner‐sphere Gd(III) coordination.
Synthesis of Novel Pyridothienopyrimidines, Pyridothienopyrimidothiazines, Pyridothienopyrimidobenzthiazoles and Triazolopyridothienopyrimidines
Authors: Bakhite Etif Y. A. , Radwan Shaban M. , El‐Dean Adel M. Kamal 
Published: May 2015

AbstractThe reaction of 3‐amino‐4,6‐dimethylthieno[2,3‐b]pyridine‐2‐carboxamide (1a) or its N‐aryl derivatives 1b‐d with carbon disulphide gave the pyridothienopyrimidines 2a‐d, whilst when the same reaction was carried out using N1‐arylidene‐3‐amino‐4,6‐dimethylthieno[2,3‐b]pyridine‐2‐carbohydrazides (1e‐h), pyridothienothiazine 3 was obtained. Also, refluxing of 1b‐d with acetic anhydride afforded oxazinone derivative 4. Compounds 2a and 2b‐d were also obtained by the treatment of thiazine 3 with ammonium acetate or aromatic amines, respectively. When compound 2a was allowed to react with arylidene malononitriles or ethyl α‐cyanocinnamate, novel pyrido[3″,2″:4′,5′]thieno[3′,2′:4,5]pyrimido[2,1‐b][1,3] thiazines 5a‐c were obtained. Treatment of 2b‐d with bromine in acetic acid furnished the disulphide derivatives 6a‐c. U.V. irradiation of 2b‐d resulted in the formation of pyrido[3″,2″:4′,5′]thieno[3′,2′:4,5]pyrimido[2,1‐b]benzthiazoles 7a‐c. The reaction of 2a‐d with some halocarbonyl compounds afforded the corresponding S‐substituted thiopyrido thienopyrimidines 8a‐j. Compound 8b was readily cyclized into the corresponding thiazolo[3″,2″‐a]‐pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine 9 upon treatment with conc. sulphuric acid. Heating of 2a,b with hydrazine hydrate in pyridine afforded the hydrazino derivatives 11a,b. Reaction of ester 8c with hydrazine hydrate in ethanol gave acethydrazide 10. Compounds 10 and 11a,b were used as versatile synthons for other new pyridothienopyrimidines 12–15 as well as [1,2,4] triazolopyridothienopyrimidines 16–19.
Heterocyclic Systems Containing Bridged Nitrogen Atom: Synthesis and Antibacterial Activity of 3‐(2‐Phenylquinolin‐4‐yl)/3‐(1‐p‐Chlorophenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazine Derivatives
Authors: Hui Xin‐Ping , Dong Heng‐Shan , Xu Peng‐Fei , Zhang Zi‐Yi , Wang Qin , Gong Yan‐Ni 
Published: May 2015

AbstractThe condensation of 4‐amino‐5‐mercapto‐3‐(2‐phenylquinolin‐4‐yl)/3‐(1‐p‐chlorophenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazoles 1a‐b with chloroacetaldehyde 2a‐b, ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone 3a‐b, chloranil 4a‐b, 2‐bromocyclohexanone 5a‐b, 2,4′‐dibromoacetophenone 6a‐b and 2‐bromo‐6′‐methoxy‐2′‐acetonaphthone 7a‐b are described. The structures of the compounds synthesized were confirmed by elemental analyses, IR, 1H NMR and mass spectra. The antibacterial activities were also evaluated.
Ene Reaction with Pummerer‐type Reaction Intermediate of α‐(Methylthio)‐N‐methoxy‐N‐methyl Acetamide: A New Synthesis of N‐methoxy‐N‐methyl‐(E,E)‐2,4‐dienamides
Authors: Lin Mei‐Ling , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching 
Published: May 2015

AbstractPummerer‐type reaction intermediate 2 of α‐(methylthio)‐N‐methoxy‐N‐methyl acetamide (1) has been found to react with 1‐alkenes to afford ene adducts 3. N‐Methoxy‐N‐methyl‐(E,E)‐2,4‐dienamides were synthesized from the adducts 3b‐f.
Taxane Diterpenoids from the Root Bark of Taiwanese Yew Taxus Mairei
Authors: Shen Ya‐Ching , Prakash Chaturvedula V. S. , Hung Meng‐Chieh 
Published: May 2015

AbstractNineteen compounds including taxumairol R (1), taxinine M (2), taxacin (3), paclitaxel (4), 10‐deacetyltaxol A (5), 10‐deacetyl‐7‐epi‐taxol (6), 7‐epi‐taxol (7), taxol C, 10‐deacetyltaxol C, 7β‐xylosyl‐10‐deacetyltaxol (8), taxamairin A (9), taxinine A, 14β‐hydroxytaxusin (10), 5α‐hydroxy‐7β,9α,10β, 13α‐tetraacetoxy‐4(20), 11‐taxadiene, 1‐dehydroxybaccatin‐VI, 1β‐dehydroxybaccatin‐IV, baccatin IV, baccatin VI and ponasterone A have been isolated and identified from the root bark of Taxus mairei. Among them, compound 1 was a new taxoid and compounds 11 and 7β‐xylosyl‐10‐deacetyltaxol pentaacetate were new derivatives prepared from 14β‐hydroxytaxusin (10) and 8, respectively. Their structures and assignment were established on the basis of 2D‐NMR analysis and chemical methods.
Mechanism of Butane Transformation
Authors: Ishaq Mohammad , Khan Mohammad Arsala , Yashima Tatsuki 
Published: May 2015

AbstractCatalytic activity and aromatic selectivity of n‐butane transformation were studied over various MFI type zeolites. From the data obtained, a reaction mechanism is suggested for different catalyst systems. It is visualized that in gallium doped catalysts, Ga3+ directly takes part both in cracking and dehydrogenation. The [Ga CH3]2+ and [GaH]2+ species formed during cracking and dehydrogenation require protonic sites for regeneration of Ga3+ species. An alternative mechanism was suggested for dehydrogenation and cracking by Ga3+ without the involvement of protonic sites. However a protonic site would be required for aromatization. In case of gallosilicates a one step mechanism is suggested for cracking and dehydrogenation reaction which does not require the presence of protonic sites in the catalyst system.
Determination of Estrogenic Nonylphenol and Bisphenol a in River Water by Solid‐Phase Extraction and Gas Chromatography‐Mass Spectrometry
Authors: Ding Wang‐Hsien , Wu Chien‐Yi 
Published: May 2015

AbstractA simple and sensitive method is presented for the analysis of nonylphenol (NP) and bisphenol A (BPA), two well known hormonally active agents (HAAs), in the samples of river water. The method involves extraction of the sample by a graphitized carbon black (GCB) solid‐phase extraction, and determination by an ion‐trap gas chromatography‐mass spectrometry (GC‐MS). The large‐volume injection technique provides high precision and sensitivity for NP and BPA, to quantitation at < 0.05 μg/L in 200 mL of water samples. Recovery of NP and BPA in spiked water samples ranged from 80% to 85%. Relative standard deviations (RSD) of replicate analyses ranged from 1.6% to 6.9%. The concentrations of NP in rivers were in the range between 0.4 to 2.4 μg/L, which were below the threshold concentration (10 μg/L) for vitellogenin induction in fish, but 78%) of water samples from five rivers exceeded the predicted‐no‐effect concentration (PNEC) of 0.7 μg/L as proposed recently. The concentrations of BPA ranged from < 0.05 μg/L to 3.0 μg/L, which all were below the PNEC of 64 μg/L.
Preparation and Characterization of Aluminum Alkoxides and their Application to Ring‐Opening Polymerization of ϵ‐Caprolactones
Authors: Yu Te‐Liang , Huang Ching‐Huei , Yang Liang‐Fu , Ko Bao‐Tsan , Lin Chu‐Chieh 
Published: May 2015

AbstractThe reaction of 2‐methoxybenzyl alcohol with one molar equiv of R2AIX in diethyl ether at 0°C gives [(2‐MeOC6H4CH2‐μ‐O)AlRX]2 (1: R = Et, X = Cl, 2: R = X = Et). In addition, 2,4‐di‐tert‐butylphenol reacts with iBu3Al affording a four‐coordinated aluminum compound [(μ‐2,4‐tBu2‐C6H4O)Al(iBu)2]2 (4). Single crystal X‐ray structure analysis of 4 shows a C2h‐symmetry with a planar Al2O2 core. Ring‐opening polymerization (ROP) of caprolactones initiated by 1, 4 and [(μ‐OCH2C6H4OMe)Al(iBu)2]2 (3) is performed and polyesters with narrow molecular weight distributions were obtained from the “living” ROP of caprolactones. 1H NMR spectroscopic studies of PCL reveal that the initiator of 1 and 3 is through the Al‐OAr function, but the initiator of 4 is through the Al‐ iBu group.
Studies of Adsorption Kinetics and Defects of Self‐Assembled Thiol Monolayers on Gold by Capacitance Plane Plot
Authors: Guo Min , Diao Peng , Tong Ruting 
Published: May 2015

AbstractThe capacitive property of an electrode/electrolyte interface can be described by complex capacitance. The capacitance plane plots (CPPs) of ideal polarized and kinetic controlled electrodes are derived based on the concept of complex capacitance. By using CPPs, the capacitance of electrode/electrolyte interface can be conveniently determined. In this work, CPPs obtained in ac impedance experiments are employed for the first time in studying the kinetics of adsorption process of the thiol monolayer. The coverage of octadecanethiol (ODT) monolayer on gold is examined as a function of adsorption time. The adsorption process of ODT molecules on gold exhibits two distinct phases: an initial rapid step followed by a slow one. The simple Langmuir model best explains our experimental data in the initial adsorption stage. CPPs and cyclic voltammetry (CV) indicate that, in the initial adsorption step, the ODT monolayer contains defects whose number decreases with the increasing of adsorption time.