共查询到20条相似文献,搜索用时 11 毫秒
1.
DFT study the interaction of β‐cyclodextrin with benzyl azide and phenyl acetylene in synthesis of 1,2,3‐triazoles
下载免费PDF全文
![点击此处可从《Journal of Physical Organic Chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The phenyl acetylene and benzyl azide cycloaddition reaction in water in the presence of β‐cyclodextrin (β‐CD) as a phase transfer catalyst (PTC) can get a better yield in a shorter time. The interaction between β‐CD and phenyl acetylene or benzyl azide plays an important role in this reaction. This paper studies the complexes of β‐CD with phenyl acetylene and benzyl azide using density functional theory (DFT) method. In order to find out the orientations of guests in the cavity of β‐CD, binding energy and deformation energy are investigated, and the calculated results are confirmed by 1H nuclear magnetic resonance (1HNMR). The data from single point energy indicate that the inclusion complexes can improve the solubilities of phenyl acetylene and benzyl azide in water. The 13C and 15N spectra show that the most obvious variation concentrates on C6 and C8 of phenyl acetylene and N15 of benzyl azide in complexes. Mulliken charge and frontier orbital are employed for revealing the charge distribution. The effect of β‐CD is discussed in terms of the calculated parameters. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
2.
3.
Ryoji Fujiyama Md. Ashadul Alam Aiko Shiiyama Toshihiro Munechika Mizue Fujio Yuho Tsuno 《Journal of Physical Organic Chemistry》2010,23(9):819-827
Solvolysis rates of 2‐(aryldimethylsilyl)‐1‐methylethyl and 2‐(aryldimethylsilyl)‐1‐tert‐butylethyl trifluoroacetates were determined conductimetrically in 60% (v/v) aqueous ethanol. The effects of aryl substituents at the silicon atom on the solvolysis rates at 50 °C were correlated with parameters of r+ = 0.15 with the Yukawa–Tsuno equation, giving ρ values of ?1.5 for both secondary α‐Me and α‐tert‐Bu systems. The ρ values for those secondary systems are less negative than ?1.75 for the 2‐(aryldimethylsilyl)ethyl system that proceeds by the Eaborn (non‐vertical) mechanism, while they are distinctly more negative than ?0.99 for 2‐(aryldimethylsilyl)‐1‐phenylethyl system that should proceed by the Lambert (vertical) mechanism. There was a fairly linear relationship between the reaction constants (ρ) for the β‐silyl substituent effects and the solvolysis reactivities for a series of β‐silyl substrates. The solvolyses of the α‐Me and tert‐Bu substrates proceed through the transition state (TS) with an appreciable degree of the β‐silyl participation, close to the Eaborn (non‐vertical) TS rather than to the Lambert (vertical) TS. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
4.
Kathleen M. Morgan Garry Brown Jr. Monique A. Pichon Geannette Y. Green 《Journal of Physical Organic Chemistry》2011,24(12):1144-1150
The base‐induced rearrangement of aziridines has been examined using a combination of calculations and experiment. The calculations show that the substituent on nitrogen is a critical feature that greatly affects the favorability of both α‐deprotonation, and β‐elimination to form an allylic amine. Experiments were carried out to determine whether E2‐like rearrangement to the allylic amine with lithium diisopropyl amide (LDA) is possible. N‐tosyl aziridines were found to deprotonate on the tosyl group, preventing further reaction. A variety of N‐benzenesulfonyl aziridines having both α‐ and β‐protons decomposed when treated with LDA in either tetrahydrofuran or hexamethylphosphoramide. However, when α‐protons were not present, allylic amine was formed, presumably via β‐elimination. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
5.
Adlane Sayede Michel Ferreira Hervé Bricout Sébastien Tilloy Eric Monflier 《Journal of Physical Organic Chemistry》2011,24(12):1129-1135
The interaction of β‐cyclodextrin (β‐CD) with meta‐trisulfonated triphenylphosphine derivatives bearing one or two methyl (or methoxy) groups on the aromatic rings has been investigated by PM3 calculations. The results show that phosphine molecules interact with β‐CD having either an unsubstituted sulfophenyl group or a substituted sulfophenyl group at the para and/or meta‐position. The presence of one methyl or methoxy group in the ortho‐position on each aromatic ring prevents the formation of an inclusion complex between meta‐trisulfonated triphenylphosphine derivatives and β‐CD. The deeply included phosphines in the β‐CD cavity show significant van der Waals interactions with β‐CD. These interactions are at the origin of the high association constants between these molecules and β‐CD. Phosphines exhibiting small association constants interact with β‐CD by forming H‐bonds and weak (or null) van der Waals interactions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
6.
Nighat Kausar Bruce D. Alexander Trevor J. Dines Robert Withnall Babur Z. Chowdhry 《Journal of Raman spectroscopy : JRS》2009,40(6):661-669
Experimental vibrational spectroscopic studies and density functional theory (DFT) calculations of the di‐amino acid peptide derivatives α‐ and β‐N‐acetyl‐L‐Asp‐L‐Glu have been undertaken. Raman and infrared spectra have been recorded for samples in the solid state. DFT simulations were conducted using the B3‐LYP correlation functional and the cc‐pVDZ basis set to determine energy minimized/geometry optimized structures (based on a single isolated molecule in the gaseous state). Normal coordinate calculations have provided vibrational assignments for fundamental modes, including their potential energy distributions. Significant differences are observed between α‐ and β‐N‐acetyl‐L‐Asp‐L‐Glu both in the computed structures and in the vibrational spectra. The combination of experimental and calculated spectra provide an insight into the structural and vibrational spectroscopic properties of di‐amino acid peptide derivatives. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Claudia Yañez Julio Basualdo Paola Jara‐Ulloa J. Arturo Squella 《Journal of Physical Organic Chemistry》2007,20(7):499-505
The interaction of estrone and estradiol with β‐cyclodextrins (βCD) was investigated by differential pulse voltammetry (DPV) and high‐performance liquid chromatography (HPLC) in mixed media. The co‐solvent influence on the tendency of these estrogens to form inclusion complexes with βCD was examined. Thus, acetonitrile (MeCN) and ethanol (EtOH) were used in a mixed aqueous medium containing phosphate buffer. The association constant of the inclusion complexes (Ka) of estrone and estradiol with βCD were determined in two different media by using both voltammetric and chromatographic techniques. Estradiol was found to bind to βCD with higher affinities than estrone, irrespective of the medium. We have also found a clear influence of the co‐solvent on the Ka value, which means a competition of co‐solvent molecules with estrogens for binding to the cavity of βCD. Consequently, interaction between βCD and the steroids is weakened when acetonitrile is used. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
8.
S. I. Nikitenko Ph. Moisy I. A. Tcharushnikova P. Blanc C. Madic 《Ultrasonics sonochemistry》2000,7(4)
Ultrasonic irradiation (22 kHz, Ar atmosphere) of Th(IV) β-diketonates Th(HFAA)4 and Th(DBM)4, where HFAA and DBM are hexafluoroacetylacetone and dibenzoylmethane respectively, causes them to decompose in hexadecane solutions, forming solid thorium compounds. The first-order rate constants for Th(IV) β-diketonate degradation were found to be (9.3±0.8)×10−3 for Th(HFAA)4 and (3.8±0.4)×10−3 min−1 for Th(DBM)4, (T=92°C, I=3 W cm−2). The rate of the sonochemical reaction increased with the rising β-diketonate volatility and decreased with the rising hydrocarbon solvent vapor pressure. Solid sonication products consisted of a mixture of thorium carbide ThC2 and Th(IV) β-diketonate partial degradation products. The average ThC2 particle size was estimated to be about 2 nm. ThC2 formation was attributed to the high-temperature reaction occurring within the cavitating bubble. The thorium β-diketonate partial degradation products formed in the liquid reaction zones surrounding the cavitating bubbles. 相似文献
9.
X. L. Yu J. Chen S. X. Wu Y. J. Liu S. W. Li 《Journal of Raman spectroscopy : JRS》2008,39(10):1440-1443
A rutile β‐MnO2 film was grown on MgO substrate using plasma‐assisted molecular beam epitaxy (PAMBE) monitored by reflection high‐energy electron diffraction (RHEED). Polarized Raman spectra at various temperatures were obtained to investigate the influence of the helimagnetic structure on the vibrational modes of β‐MnO2. A red shift of Eg modes indicates a gradual formation of spin angles between neighboring Mn4+ ions. The intensities of the Eg and A1g modes with y‐polarized incidence increase remarkably below the Néel temperature. A new view as vibrational mode projection (VMP) indicates the interactions between the magnetic component of incident light and the helimagnetic structure. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
10.
Alla Synytsya Petr Alexa Jorrit de Boer Markus Loewe Martin Moosburger Michael Würkner Karel Volka 《Journal of Raman spectroscopy : JRS》2007,38(12):1646-1655
Raman spectroscopy was applied to analyse structural changes in serum albumins (bovine serum albumin, BSA; human serum albumin, HSA) following proton and γ‐irradiation (0.5, 5 and 50 Gy). Characteristic Raman bands of both polypeptide backbone and amino acid residues were sensitive to irradiation. Significant damage of HSA/BSA was observed only at the highest dose (50 Gy). Raman spectra confirmed radiation‐induced denaturation, destruction of helical structures and aggregation of serum albumins. The differences in the dose‐dependent effects of proton and γ‐radiation on studied proteins are discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
11.
Zhu‐Bing Xu Sheng Pan Yi Yang Jia‐Dan Xue Xuming Zheng Bin‐Bin Xie Wei‐Hai Fang 《Journal of Raman spectroscopy : JRS》2014,45(6):438-447
The photophysics of 3‐methyl‐3‐pentene‐2‐one (3M3P2O) after excitation to the S2(ππ*) electronic state were studied using the resonance Raman spectroscopy and complete active space self‐consistent field (CASSCF) method calculations. The A‐band resonance Raman spectra were obtained in cyclohexane, acetonitrile, and methanol with excitation wavelengths in resonance with the first intense absorption band to probe the structural dynamics of 3M3P2O. The B3LYP‐TD/6‐31++G(d, p) computation was carried out to determine the relative A‐band resonance Raman intensities of the fundamental modes, and the result was used to reproduce the corresponding fundamental band intensities of the 223.1 nm resonance Raman spectrum and thus to examine whether the vibronic‐coupling existed in Franck‐Condon region or not. CASSCF calculations were carried out to determine the minimal singlet excitation energies of S1, FC, S1,min (nπ*), S2, FC, S2,min (ππ*), the transition energies of the conical intersection points Sn/Sπ, Sn/S0, and the optimized excited state geometries as well as the geometry structures of the conical intersection points. The A‐band short‐time structural dynamics and the corresponding decay dynamics of 3M3P2O were obtained by the analysis of the resonance Raman intensity pattern and CASSCF computations. It was revealed that the initial structural dynamics of 3M3P2O was towards the simultaneous C3=C4 and C2=O7 bond elongation, with the C3=C4 bond length lengthening greater at the very beginning, whereas the C2=O7 bond length changing greater at the later evolution time before reaching the CI(S2/S1) conical intersection point. The decay dynamics from S2(ππ*) to S1(nπ*) via S2(ππ*)/S1(nπ*) in singlet realm and from S1(nπ*) to T1(nπ*) via ISC[S1(nπ*)/T2(ππ*)/T1(nπ*)] in triplet realm are proposed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Sergio L. Laurella Claudia Latorre Roque Dietrich Jorge J. P. Furlong Patricia E. Allegretti 《Journal of Physical Organic Chemistry》2012,25(12):1365-1373
Mass spectrometric evidence of tautomerism is reported for β‐ketoamides. The most abundant tautomers are ketoamido and Z‐enolamido (both forming internal hydrogen bonds). The influence of temperature on the enol/keto abundance ratios is studied in order to estimate the enthalpy difference for tautomeric equilibria. Theoretical calculations have been done in order to support experimental determinations. There are consistent trends between theoretical and experimental data: Enolization is favored by electron‐withdrawing substiuents, bulky groups in α position and temperature increase. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
13.
Xiaoqi Fu Fengli Bei Xin Wang Xujie Yang Lude Lu 《Journal of Raman spectroscopy : JRS》2009,40(9):1290-1295
We report surface‐enhanced Raman scattering (SERS) spectra from 4‐mercaptopyridine (4‐Mpy) adsorbed on sub‐monolayers of α‐Fe2O3 nanocrystals (sphere, spindle, cube). The maximum enhancement factor has been estimated to be about 104 compared to that of 4‐Mpy in solution. A possible mechanism has been proposed that the charge transfer between the α‐Fe2O3 nanocrystals and the 4‐Mpy molecules is most likely responsible for the observed enhancement of Raman intensity of adsorbed 4‐Mpy molecules as surface plasmon resonances have not occurred. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
14.
E. M. Therézio J. L. Duarte E. Laureto E. Di Mauro I. L. Dias A. Marletta H. de Santana 《Journal of Physical Organic Chemistry》2011,24(8):640-645
In this work, poly(3‐octylthiophene) (P3OT) films were synthesized electrochemically in non‐aqueous media through the oxidation of the monomer, (3‐octylthiophene), using a standard three‐electrode cell in acetonitrile with 0.05 mol L?1 LiClO4 or 0.05 mol L?1 Et4NBF4. The polymeric films were deposited on fluorine tin oxide (FTO). The partial dedoping was obtained in NH4OH solution, providing a good chemical stability of the formed material. The films obtained through this method have been characterized by Fourier‐transform infrared spectroscopy (FT‐IR), electron paramagnetic resonance (EPR), UV–Vis absorption, and photoluminescence (PL) spectroscopy. The FT‐IR and EPR spectra together gave the results that led to characterization of two structures (pristine and non‐pristine forms of thiophene rings) while forming the P3OT polymer chain. These results were associated with the stabilization of pristine chains and mixed chains (non‐pristine structures) in the polymeric film. Their bands in the PL spectra are wide and asymmetric and their adjustments by Gaussian functions was necessary; this was the main indication that there are two distinct contributions to the emission spectra. These two contributions are attributed to the emission by mixed chains (Gaussian centered at higher energy) and by pristine chains (Gaussian of lower energy) present in the formed polymeric material. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
Alla Synytsya Petr Alexa Jorrit de Boer Markus Loewe Martin Moosburger Michael Würkner Karel Volka 《Journal of Raman spectroscopy : JRS》2007,38(11):1406-1415
Raman spectroscopy was applied to analyse structural changes in calf thymus double‐stranded deoxyribonucleic acid (dsDNA) after proton‐ and γ‐irradiation (0.5, 5 and 50 Gy). Characteristic Raman bands of phosphodiester linkages, nucleic bases and deoxyribose moieties were sensitive to irradiation. A significant damage of the macromolecules was observed only at the highest dose (50 Gy) of both types of radiations. Spectral changes confirmed a radiation‐induced alteration of the native structure of dsDNA. Nucleic bases, especially pyrimidines, were the most sensitive to radiation, while some alterations in the sugar–phosphate backbone were also detected. The differences in the dose‐dependent effects of proton vs γ‐irradiation on studied biomolecule are discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
16.
S. Cint Pinzaru Cs. Müller S. Tomi M. M. Venter B. I. Cozar B. Glamuzina 《Journal of Raman spectroscopy : JRS》2015,46(7):597-604
While recording SERS spectra of pure β‐carotene at sub‐micromole concentrations for reference purpose, we discovered an unusual spectral response never reported before. In pre‐resonance conditions with the 532‐nm line, SERS of β‐carotene with AgNPs exhibits among the strong υ(CC) mode at 1512 cm−1 unshifted from normal Raman spectrum, additional strong bands at 1649, 1575 and 1387 cm−1 as well as other medium bands not observed in the Raman spectrum of the crystalline powder. Such behavior is explained in terms of selection rules relaxation upon cyclohexene terminal rings of the β‐carotene interaction with the NP surface. AFM images of the SERS system suggested dimers and trimers clustering of the nanoparticles with adsorbed β‐carotene. In light of the new SERS feature the consequences in correct interpretation of the SERS imaging from complex biosystems containing carotenoids are discussed. Relative intensity ratio of the β‐carotene band at 1512 cm−1 and water against concentration allowed a reliable SERS calibration curve for 50 to 500 nmol l−1 concentration range and provided quantitative SERS assessment of the carotenoid content in the sea urchin (Paracentrotus lividus) gonads extracts. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
Rita Baddour‐Hadjean Mikhail B. Smirnov V. Yu Kazimirov Konstantin S. Smirnov Jean‐Pierre Pereira‐Ramos 《Journal of Raman spectroscopy : JRS》2015,46(4):406-412
Structure and vibrational dynamics of γ′‐V2O5 synthesized from a pristine γ‐LiV2O5 sample via a chemical oxidation route was studied by means of Raman spectroscopy and quantum‐chemical calculations. The calculations based on density functional theory reliably reproduce the experimental structure of the γ′‐V2O5 lattice. The calculated Raman spectrum agrees remarkably well with the experimental one. Making use of the agreement, a complete assignment of Raman bands to vibrations of particular structural units is proposed. The comparison of Raman spectra and structural features of α‐V2O5 and γ′‐V2O5 polymorphs allowed establishing reliable ‘structure–spectrum’ correlations and identifying Raman peaks characteristic for different structural units. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
18.
Hanan Alolaiyan Halimah A. Alshehri Muhammad Haris Mateen Dragan Pamucar Muhammad Gulzar 《Entropy (Basel, Switzerland)》2021,23(8)
A complex fuzzy set is a vigorous framework to characterize novel machine learning algorithms. This set is more suitable and flexible compared to fuzzy sets, intuitionistic fuzzy sets, and bipolar fuzzy sets. On the aspects of complex fuzzy sets, we initiate the abstraction of -complex fuzzy sets and then define -complex fuzzy subgroups. Furthermore, we prove that every complex fuzzy subgroup is an -complex fuzzy subgroup and define -complex fuzzy normal subgroups of given group. We extend this ideology to define -complex fuzzy cosets and analyze some of their algebraic characteristics. Furthermore, we prove that -complex fuzzy normal subgroup is constant in the conjugate classes of group. We present an alternative conceptualization of -complex fuzzy normal subgroup in the sense of the commutator of groups. We establish the -complex fuzzy subgroup of the classical quotient group and show that the set of all -complex fuzzy cosets of this specific complex fuzzy normal subgroup form a group. Additionally, we expound the index of -complex fuzzy subgroups and investigate the -complex fuzzification of Lagrange’s theorem analog to Lagrange’ theorem of classical group theory. 相似文献
19.
Yamir Bandala Judit Aviña Tania González Ignacio A. Rivero Eusebio Juaristi 《Journal of Physical Organic Chemistry》2008,21(5):349-358
Thirty‐four novel α/β‐tetrapeptides ( 1–34 ) have been prepared employing solid‐phase and in‐parallel synthetic protocols. α/β ‐Tetrapeptides 1 – 34 were prepared by a combination of three α‐amino acid residues (alanine (Ala), phenylalanine (Phe), and isoleucine (Ile)) with one β‐amino acid residue (β3‐homophenylglycine). The corresponding complexes of several selected α/β‐tetrapeptides with alkali, alkaline earth, and transition metals, [tP + M+], were evaluated using ion electrospray‐ionization mass spectrometry (ESI‐MS). According to the results from analysis of mixtures, we can conclude that the position of the β‐amino acid is determinant in the affinity toward different metal cations. Computational modeling (DFT, B3LYP 6‐311++G) provided useful information regarding the most likely coordination sites of the metal ions on the receptor α/β‐tetrapeptide 12 , HO2C‐α‐Phe‐α‐Phe‐α‐Ile‐β3‐hPhg‐NH2, as well as the conformational changes induced by the metal upon [tP + M+] complex formation. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献