共查询到20条相似文献,搜索用时 281 毫秒
1.
Ken Taguchi Akihiko Toda Hironori Hondoh Satoru Ueno Kiyotaka Sato 《Molecules (Basel, Switzerland)》2021,26(1)
The crystallization behavior of the metastable form of triacylglycerols (TAGs) plays a critical role as a precursor for the crystallization of more stable and forms for various applications in food and pharmaceutical products. However, precise analysis of the crystallization kinetics of has not been performed, likely due to its rapid and complex behavior. This paper presents the observation results of the initial stages of the isothermal crystallization kinetics of forms of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (rac-PPO), and molecular compound (MC) crystals of a POP/rac-PPO (1/1) mixture (MC) using synchrotron radiation time-resolved X-ray diffraction and polarized optical microscopy. In all the TAGs, crystals with a worm-like morphology started to grow rapidly in the first stage. Then, the crystals slowly transformed into more stable forms in different manners for different TAG samples. In POP, the conversion was simple, as the -2 form transformed into -3, whereas in rac-PPO, the lamellar distance values of the -2 form continuously decreased with time and changed into the -3 form. In the MC crystals, in contrast, separate crystallization of -2 of a rac-PPO fraction initially occurred, followed by the crystallization of -2 of POP, and the two forms merged into -2 of MC. This separate crystallization was caused by large differences in the crystallization kinetics of the forms of POP and rac-PPO. 相似文献
2.
Massimiliano Bartolomei Paul Martini Ricardo Prez de Tudela Toms Gonzlez-Lezana Marta I. Hernndez Jos Campos-Martínez Javier Hernndez-Rojas Jos Bretn Paul Scheier 《Molecules (Basel, Switzerland)》2021,26(12)
We present a combined experimental and theoretical investigation on Ca ions in helium droplets, HeCa. The clusters have been formed in the laboratory by means of electron-impact ionization of Ca-doped helium nanodroplets. Energies and structures of such complexes have been computed using various approaches such as path integral Monte Carlo, diffusion Monte Carlo and basin-hopping methods. The potential energy functions employed in these calculations consist of analytical expressions following an improved Lennard-Jones formula whose parameters are fine-tuned by exploiting ab initio estimations. Ion yields of HeCa -obtained via high-resolution mass spectrometry- generally decrease with N with a more pronounced drop between and , the computed quantum HeCa evaporation energies resembling this behavior. The analysis of the energies and structures reveals that covering Ca with 17 He atoms leads to a cluster with one of the smallest energies per atom. As new atoms are added, they continue to fill the first shell at the expense of reducing its stability, until , which corresponds to the maximum number of atoms in that shell. Behavior of the evaporation energies and radial densities suggests liquid-like cluster structures. 相似文献
3.
Diego T. Gomez Lawrence R. Pratt David M. Rogers Susan B. Rempe 《Molecules (Basel, Switzerland)》2021,26(11)
With a longer-term goal of addressing the comparative behavior of the aqueous halides F, Cl, Br, and I on the basis of quasi-chemical theory (QCT), here we study structures and free energies of hydration clusters for those anions. We confirm that energetically optimal clusters, with X = Cl, Br, and I, exhibit surface hydration structures. Computed free energies, based on optimized surface hydration structures utilizing a harmonic approximation, typically (but not always) disagree with experimental free energies. To remedy the harmonic approximation, we utilize single-point electronic structure calculations on cluster geometries sampled from an AIMD (ab initio molecular dynamics) simulation stream. This rough-landscape procedure is broadly satisfactory and suggests unfavorable ligand crowding as the physical effect addressed. Nevertheless, this procedure can break down when , with the characteristic discrepancy resulting from a relaxed definition of clustering in the identification of clusters, including ramified structures natural in physical cluster theories. With ramified structures, the central equation for the present rough-landscape approach can acquire some inconsistency. Extension of these physical cluster theories in the direction of QCT should remedy that issue, and should be the next step in this research direction. 相似文献
4.
Lars Esser Roberto Macchieraldo Roman Elfgen Melanie Sieland Bernd Michael Smarsly Barbara Kirchner 《Molecules (Basel, Switzerland)》2021,26(1)
To gain a deeper understanding of the TiCl solvation effects in multi-component ionic liquids, we performed ab initio molecular dynamics simulations of 1-butyl-3-methylimidazolium [CCIm], tetrafluoroborate [BF], chloride [Cl] both with and without water and titanium tetrachloride TiCl. Complex interactions between cations and anions are observed in all investigated systems. By further addition of water and TiCl this complex interaction network is extended. Observations of the radial distribution functions and number integrals show that water and TiCl not only compete with each other to interact mainly with [Cl], which strongly influences the cation-[BF] interaction, but also interact with each other, which leads to the fact that in certain systems the cation-anion interaction is enhanced. Further investigations of the Voronoi polyhedra analysis have demonstrated that water has a greater impact on the nanosegregated system than TiCl which is also due to the fact of the shear amount of water relative to all other components and its higher mobility compared to TiCl. Overall, the polar network of the IL mixture collapses by including water and TiCl. In the case of [Cl] chloride enters the water continuum, while [BF] remains largely unaffected, which deeply affects the interaction of the ionic liquid (IL) network. 相似文献
5.
We present a combined quantum mechanics/molecular mechanics (QM/MM) molecular dynamics–statistical approach for the interpretation of nuclear magnetic resonance (NMR) chemical shift patterns in phycocyanobilin (PCB). These were originally associated with colour tuning upon photoproduct formation in red/green-absorbing cyanobacteriochrome AnPixJg2 and red/far-red-absorbing phytochrome Cph12. We pursue an indirect approach without computation of the absorption frequencies since the molecular geometry of cofactor and protein are not accurately known. Instead, we resort to a heuristic determination of the conjugation length in PCB through the experimental NMR chemical shift patterns, supported by quantum chemical calculations. We have found a characteristic correlation pattern of C chemical shifts to specific bond orders within the -conjugated system, which rests on the relative position of carbon atoms with respect to electron-withdrawing groups and the polarisation of covalent bonds. We propose the inversion of this regioselective relationship using multivariate statistics and to apply it to the known experimental NMR chemical shifts in order to predict changes in the bond alternation pattern. Therefrom the extent of electronic conjugation, and eventually the change in absorption frequency, can be derived. In the process, the consultation of explicit mesomeric formulae plays an important role to qualitatively account for possible conjugation scenarios of the chromophore. While we are able to consistently associate the NMR chemical shifts with hypsochromic and bathochromic shifts in the P and P, our approach represents an alternative method to increase the explanatory power of NMR spectroscopic data in proteins. 相似文献
6.
Zahir Shah Rashid Jan Poom Kumam Wejdan Deebani Meshal Shutaywi 《Molecules (Basel, Switzerland)》2021,26(6)
Human immunodeficiency virus (HIV) is a life life-threatening and serious infection caused by a virus that attacks T-cells, which fight against infections and make a person susceptible to other diseases. It is a global public health problem with no cure; therefore, it is highly important to study and understand the intricate phenomena of HIV. In this article, we focus on the numerical study of the path-tracking damped oscillatory behavior of a model for the HIV infection of T-cells. We formulate fractional dynamics of HIV with a source term for the supply of new CD4+ T-cells depending on the viral load via the Caputo–Fabrizio derivative. In the formulation of fractional HIV dynamics, we replaced the constant source term for the supply of new T-cells from the thymus with a variable source term depending on the concentration of the viral load, and introduced a term that describes the incidence of the HIV infection of T-cells. We present a novel numerical scheme for fractional view analysis of the proposed model to highlight the solution pathway of HIV. We inspect the periodic and chaotic behavior of HIV for the given values of input factors using numerical simulations. 相似文献
7.
Danillo Valverde Adalberto V. S. de Araújo Antonio Carlos Borin 《Molecules (Basel, Switzerland)》2021,26(17)
The photophysical relaxation mechanisms of 1-cyclohexyluracil, in vacuum and water, were investigated by employing the Multi-State CASPT2 (MS-CASPT2, Multi-State Complete Active-Space Second-Order Perturbation Theory) quantum chemical method and Dunning’s cc-pVDZ basis sets. In both environments, our results suggest that the primary photophysical event is the population of the bright state. Afterwards, two likely deactivation pathways can take place, which is sustained by linear interpolation in internal coordinates defined via Z-Matrix scans connecting the most important characteristic points. The first one (Route 1) is the same relaxation mechanism observed for uracil, its canonical analogue, i.e., internal conversion to the ground state through an ethylenic-like conical intersection. The other route (Route 2) is the direct population transfer from the bright state to the triplet state via an intersystem crossing process involving the (/) singlet-triplet crossing point. As the spin-orbit coupling is not too large in either environment, we propose that most of the electronic population initially on the state returns to the ground following the same ultrafast deactivation mechanism observed in uracil (Route 1), while a smaller percentage goes to the triplet manifold. The presence of a minimum on the potential energy hypersurface in water can help to understand why experimentally it is noticed suppression of the triplet states population in polar protic solvent. 相似文献
8.
The S2 state produces two basic electron paramagnetic resonance signal types due to the manganese cluster in oxygen-evolving complex, which are influenced by the solvents, and cryoprotectant added to the photosystem II samples. It is presumed that a single manganese center oxidation occurs on S1 → S2 state transition. The S2 state has readily visible multiline and electron paramagnetic resonance signals and hence it has been the most studied of all the Kok cycle intermediates due to the ease of experimental preparation and stability. The S2 state was studied using electron paramagnetic resonance spectroscopy at X-band frequencies. The aim of this study was to determine the spin states of the signal. The multiline signal was observed to arise from a ground state spin ½ centre while the 4.1 signal generated at ≈140 K NIR illumination was proposed to arise from a spin center with rhombic distortion. The ‘ground’ state 4.1 signal was generated solely or by conversion from the multiline. The data analysis methods used involved numerical simulations of the experimental spectra on relevant models of the oxygen-evolving complex cluster. A strong focus in this paper was on the ‘ground’ state 4.1 signal, whether it is a rhombic spin state signal or an axial spin state signal. The data supported an X-band CW-EPR-generated 4.1 signal as originating from a near rhombic spin 5/2 of the S2 state of the PSII manganese cluster. 相似文献
9.
The bipartite entanglement in pure and mixed states of a quantum spin-1 Heisenberg dimer with exchange and uniaxial single-ion anisotropies is quantified through the negativity in a presence of the external magnetic field. At zero temperature the negativity shows a marked stepwise dependence on a magnetic field with two abrupt jumps and plateaus, which can be attributed to the quantum antiferromagnetic and quantum ferrimagnetic ground states. The magnetic-field-driven phase transition between the quantum antiferromagnetic and quantum ferrimagnetic ground states manifests itself at nonzero temperatures by a local minimum of the negativity, which is followed by a peculiar field-induced rise of the negativity observable in a range of moderately strong magnetic fields. The rising temperature generally smears out abrupt jumps and plateaus of the negativity, which cannot be distinguished in the relevant dependencies above a certain temperature. It is shown that the thermal entanglement is most persistent against rising temperature at the magnetic field, for which an energy gap between a ground state and a first excited state is highest. Besides, temperature variations of the negativity of the spin-1 Heisenberg dimer with an easy-axis single-ion anisotropy may exhibit a singular point-kink, at which the negativity has discontinuity in its first derivative. The homodinuclear nickel complex [Ni(Medpt)(-ox)(HO)](ClO)·2HO provides a suitable experimental platform of the antiferromagnetic spin-1 Heisenberg dimer, which allowed us to estimate a strength of the bipartite entanglement between two exchange-coupled Ni magnetic ions on the grounds of the interaction constants reported previously from the fitting procedure of the magnetization data. It is verified that the negativity of this dinuclear compound is highly magnetic-field-orientation dependent due to presence of a relatively strong uniaxial single-ion anisotropy. 相似文献
10.
Multiple zigzag chains of length n and width m constitute an important class of regular graphene flakes of rectangular shape. The physical and chemical properties of these basic pericondensed benzenoids can be related to their various topological invariants, conveniently encoded as the coefficients of a combinatorial polynomial, usually referred to as the ZZ polynomial of multiple zigzag chains . The current study reports a novel method for determination of these ZZ polynomials based on a hypothesized extension to John–Sachs theorem, used previously to enumerate Kekulé structures of various benzenoid hydrocarbons. We show that the ZZ polynomial of the multiple zigzag chain can be conveniently expressed as a determinant of a Toeplitz (or almost Toeplitz) matrix of size consisting of simple hypergeometric polynomials. The presented analysis can be extended to generalized multiple zigzag chains , i.e., derivatives of with a single attached polyacene chain of length k. All presented formulas are accompanied by formal proofs. The developed theoretical machinery is applied for predicting aromaticity distribution patterns in large and infinite multiple zigzag chains and for computing the distribution of spin densities in biradical states of finite multiple zigzag chains . 相似文献
11.
Francesco Ferdinando Summa Guglielmo Monaco Riccardo Zanasi Stefano Pelloni Paolo Lazzeretti 《Molecules (Basel, Switzerland)》2021,26(14)
The electric dipole–magnetic dipole polarizability tensor , introduced to interpret the optical activity of chiral molecules, has been expressed in terms of a series of density functions , which can be integrated all over the three-dimensional space to evaluate components and trace . A computational approach to , based on frequency-dependent electronic current densities induced by monochromatic light shining on a probe molecule, has been developed. The dependence of on the origin of the coordinate system has been investigated in connection with the corresponding change of . It is shown that only the trace of the density function defined via dynamic current density evaluated using the continuous translation of the origin of the coordinate system is invariant of the origin. Accordingly, this function is recommended as a tool that is quite useful for determining the molecular domains that determine optical activity to a major extent. A series of computations on the hydrogen peroxide molecule, for a number of different HO–OH dihedral angles, is shown to provide a pictorial documentation of the proposed method. 相似文献
12.
Steven van Terwingen Daniel Brüx Ruimin Wang Ulli Englert 《Molecules (Basel, Switzerland)》2021,26(13)
In the hydrochloride of a pyrazolyl-substituted acetylacetone, the chloride anion is hydrogen-bonded to the protonated pyrazolyl moiety. Equimolar co-crystallization with tetrafluorodiiodobenzene (TFDIB) leads to a supramolecular aggregate in which TFDIB is situated on a crystallographic center of inversion. The iodine atom in the asymmetric unit acts as halogen bond donor, and the chloride acceptor approaches the -hole of this TFDIB iodine subtending an almost linear halogen bond, with Cl···I = Å and Cl···I–C = 179.32(6)°. This contact is roughly orthogonal to the N–H···Cl hydrogen bond. An analysis of the electron density according to Bader’s Quantum Theory of Atoms in Molecules confirms bond critical points (bcps) for both short contacts, with = 0.129 for the halogen and e for the hydrogen bond. Our halogen-bonded adduct represents the prototype for a future class of co-crystals with tunable electron density distribution about the -hole contact. 相似文献
13.
Maximilian Paradiz Dominguez Begüm Demirkurt Marion Grzelka Daniel Bonn Laurent Galmiche Pierre Audebert Albert M. Brouwer 《Molecules (Basel, Switzerland)》2021,26(19)
Tetrazines with branched alkoxy substituents are liquids at ambient temperature that despite the high chromophore density retain the bright orange fluorescence that is characteristic of this exceptional fluorophore. Here, we study the photophysical properties of a series of alkoxy-tetrazines in solution and as neat liquids. We also correlate the size of the alkoxy substituents with the viscosity of the liquids. We show using time-resolved spectroscopy that intersystem crossing is an important decay pathway competing with fluorescence, and that its rate is higher for 3,6-dialkoxy derivatives than for 3-chloro-6-alkoxytetrazines, explaining the higher fluorescence quantum yields for the latter. Quantum chemical calculations suggest that the difference in rate is due to the activation energy required to distort the tetrazine core such that the and the higher-lying states cross, at which point the spin-orbit coupling exceeding 10 cm allows for efficient intersystem crossing to occur. Femtosecond time-resolved anisotropy studies in solution allow us to measure a positive relationship between the alkoxy chain lengths and their rotational correlation times, and studies in the neat liquids show a fast decay of the anisotropy consistent with fast exciton migration in the neat liquid films. 相似文献
14.
Thomas Raistrick Matthew Reynolds Helen F. Gleeson Johan Mattsson 《Molecules (Basel, Switzerland)》2021,26(23)
Liquid Crystal Elastomers (LCEs) combine the anisotropic ordering of liquid crystals with the elastic properties of elastomers, providing unique physical properties, such as stimuli responsiveness and a recently discovered molecular auxetic response. Here, we determine how the molecular relaxation dynamics in an acrylate LCE are affected by its phase using broadband dielectric relaxation spectroscopy, calorimetry and rheology. Our LCE is an excellent model system since it exhibits a molecular auxetic response in its nematic state, and chemically identical nematic or isotropic samples can be prepared by cross-linking. We find that the glass transition temperatures () and dynamic fragilities are similar in both phases, and the -dependence of the relaxation shows a crossover at the same for both phases. However, for , the behavior becomes Arrhenius for the nematic LCE, but only more Arrhenius-like for the isotropic sample. We provide evidence that the latter behavior is related to the existence of pre-transitional nematic fluctuations in the isotropic LCE, which are locked in by polymerization. The role of applied strain on the relaxation dynamics and mechanical response of the LCE is investigated; this is particularly important since the molecular auxetic response is linked to a mechanical Fréedericksz transition that is not fully understood. We demonstrate that the complex Young’s modulus and the relaxation time remain relatively unchanged for small deformations, whereas for strains for which the auxetic response is achieved, significant increases are observed. We suggest that the observed molecular auxetic response is coupled to the strain-induced out-of-plane rotation of the mesogen units, in turn driven by the increasing constraints on polymer configurations, as reflected in increasing elastic moduli and relaxation times; this is consistent with our recent results showing that the auxetic response coincides with the emergence of biaxial order. 相似文献
15.
Water borane (BHOH) and borinic acid (BHOH) have been proposed as intermediates along the pathway of hydrogen generation from simple reactants: water and borane. However, the vibrational spectra for neither water borane nor borinic acid has been investigaged experimentally due to the difficulty of isolating them in the gas phase, making accurate quantum chemical predictions for such properties the most viable means of their determination. This work presents theoretical predictions of the full rotational and fundamental vibrational spectra of these two potentially application-rich molecules using quartic force fields at the CCSD(T)-F12b/cc-pCVTZ-F12 level with additional corrections included for the effects of scalar relativity. This computational scheme is further benchmarked against the available gas-phase experimental data for the related borane and HBO molecules. The differences are found to be within 3 cm for the fundamental vibrational frequencies and as close as 15 MHz in the and principal rotational constants. Both BHOH and BHOH have multiple vibrational modes with intensities greater than 100 km mol, namely and in BHOH, and , , , , and in BHOH. Finally, BHOH has a large dipole moment of 4.24 D, which should enable it to be observable by rotational spectroscopy, as well. 相似文献
16.
Meei-Ju Yang Shwu-Yuan Lee Chieh-I Liu Shih-Hsuan Chen Iou-Zen Chen Tsung-Chen Su Jeu-Ming P. Yuann Chien-Wei Cheng Shiuh-Tsuen Huang Ji-Yuan Liang 《Molecules (Basel, Switzerland)》2020,25(24)
Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl3) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl3 and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical () was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl3 treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl3, while AlCl3 did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl3 inhibited the photolytic formation of and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl3 acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride () and 1 mM oxalate () ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl3 and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI. 相似文献
17.
Karol Kuacz Micha Poche Aneta Jezierska Jarosaw J. Panek 《Molecules (Basel, Switzerland)》2021,26(18)
Our long-term investigations have been devoted the characterization of intramolecular hydrogen bonds in cyclic compounds. Our previous work covers naphthazarin, the parent compound of two systems discussed in the current work: 2,3-dimethylnaphthazarin (1) and 2,3-dimethoxy-6-methylnaphthazarin (2). Intramolecular hydrogen bonds and substituent effects in these compounds were analyzed on the basis of Density Functional Theory (DFT), Møller–Plesset second-order perturbation theory (MP2), Coupled Clusters with Singles and Doubles (CCSD) and Car-Parrinello Molecular Dynamics (CPMD). The simulations were carried out in the gas and crystalline phases. The nuclear quantum effects were incorporated a posteriori using the snapshots taken from ab initio trajectories. Further, they were used to solve a vibrational Schrödinger equation. The proton reaction path was studied using B3LYP, B97XD and PBE functionals with a 6-311++G(2d,2p) basis set. Two energy minima (deep and shallow) were found, indicating that the proton transfer phenomena could occur in the electronic ground state. Next, the electronic structure and topology were examined in the molecular and proton transferred (PT) forms. The Atoms In Molecules (AIM) theory was employed for this purpose. It was found that the hydrogen bond is stronger in the proton transferred (PT) forms. In order to estimate the dimers’ stabilization and forces responsible for it, the Symmetry-Adapted Perturbation Theory (SAPT) was applied. The energy decomposition revealed that dispersion is the primary factor stabilizing the dimeric forms and crystal structure of both compounds. The CPMD results showed that the proton transfer phenomena occurred in both studied compounds, as well as in both phases. In the case of compound 2, the proton transfer events are more frequent in the solid state, indicating an influence of the environmental effects on the bridged proton dynamics. Finally, the vibrational signatures were computed for both compounds using the CPMD trajectories. The Fourier transformation of the autocorrelation function of atomic velocity was applied to obtain the power spectra. The IR spectra show very broad absorption regions between 700 cm–1700 cm and 2300 cm–3400 cm in the gas phase and 600 cm–1800 cm and 2200 cm–3400 cm in the solid state for compound 1. The absorption regions for compound 2 were found as follows: 700 cm–1700 cm and 2300 cm–3300 cm for the gas phase and one broad absorption region in the solid state between 700 cm and 3100 cm. The obtained spectroscopic features confirmed a strong mobility of the bridged protons. The inclusion of nuclear quantum effects showed a stronger delocalization of the bridged protons. 相似文献
18.
The mechanism of the carbonylation of diazomethane in the presence of iron–carbonyl–phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO)3(P) precursor followed by the diazoalkane coordination and the N2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF3 and PPh3 containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger -acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA–NOCV) calculations, diazomethane in the Fe(CO)3(phosphine)(η1-CH2N2) adduct reveals a -donor–-acceptor type of coordination. 相似文献
19.
Daniel F. Kawano Bruna Z. Costa Katherine L. Romero-Orejn Hugo C. Loureiro Dosil P. de Jesus Anita J. Marsaioli 《Molecules (Basel, Switzerland)》2021,26(9)
1-Pyrrolines are important intermediates of active natural products, such as the 2,5-dialkyl-1-pyrroline derivatives found in fire ant venoms. Here, 5-hexyl-2-methyl-3,4-dihydro-2H-pyrrole was synthesized by the enzymatic transamination/cyclization of 2,5-undecadione, and enantiodifferenciation was successfully achieved by capillary electrophoresis with sulfobutyl ether--cyclodextrin as the chiral selector. The rationale of the enantiomeric discrimination was based on the results of a docking simulation that revealed the higher affinity of (S)-5-hexyl-2-methyl-3,4-dihydro-2H-pyrrole for the sulfobutyl ether--cyclodextrin. 相似文献
20.
Hamza Ferkous Kaouther Kerboua Oualid Hamdaoui Naoufel Haddour Abdulaziz Alghyamah 《Molecules (Basel, Switzerland)》2021,26(18)
In this paper, the degradation of the diazo dye naphthol blue black (NBB) using the Galvano-Fenton process is studied experimentally and numerically. The simulations are carried out based on the anodic, cathodic, and 34 elementary reactions evolving in the electrolyte, in addition to the oxidative attack of NBB by at a constant rate of during the initiation stage of the chain reactions. The selection of the operating conditions including the pH of the electrolyte, the stirring speed, and the electrodes disposition is performed by assessing the kinetics of NBB degradation; these parameters are set to 3, 350 rpm and a parallel disposition with a 3 cm inter-electrode distance, respectively. The kinetics of in the electrolyte were monitored using the principles of Fricke dosimetry and simulated numerically. The model showed more than a 96% correlation with the experimental results in both the blank test and the presence of the dye. The effects of and concentrations on the degradation of the dye were examined jointly with the evolution of the simulated , , and concentrations in the electrolyte. The model demonstrated a good correlation with the experimental results in terms of the initial degradation rates, with correlation coefficients exceeding 98%. 相似文献