Study Of Solvent Effects Research Articles

A computational study on the detection properties of pristine, Al-, and Ga- doped Zn12O12 nanoclusters toward Deferiprone in gas and solvent phases

Electrochemical sensors have great potential in point-of-care diagnostic devices, benefiting from advancements in nanomaterials that enhance sensitivity and selectivity and reduce costs. This study theoretically investigates Deferiprone (DEF) sensing using pristine and aluminum – and gallium-doped Zn12O12 nanoclusters (AlZn11O12 and GaZn11O12) through a density functional theory (DFT) approach at the B3LYP-D level with a 6-311G (d, p) basis set. The results indicate DEF adsorption energies of −29.53 kcal mol−1 for Zn12O12, −42.19 kcal mol−1 for AlZn11O12, and −27.12 kcal mol−1 for GaZn11O12 in their most stable orientations. The adsorption of DEF significantly alters the energy gap (Eg) in the doped nanoclusters, highlighting the superior sensitivity of AlZn11O12 and GaZn11O12 for DEF detection. Transition theory calculations reveal a practical recovery time of 72.64 s for GaZn11O12, indicating favourable adsorption characteristics. Solvent effect studies show that the DEF/GaZn11O12 complex is stable in water, with a higher dipole moment reflecting increased water polarisation. UV-Vis analysis demonstrates that DEF adsorption on GaZn11O12 shifts the spectrum to higher wavelengths, indicating enhanced adsorption. Thus, GaZn11O12 is proposed as a promising candidate for DEF detection in both gas and solvent phases.

Solvent effect, DFT and NLO studies of A–π–D–π–A and A–π–D–π–D push–pull chromophore of 1,2-diazepin-4-ol based derivatives with optical limiting application

The nonlinear optical properties of push–pull chromophores, namely (E)-7-(4-bromophenyl)-2,5-bis(4-nitrophenyl)-3,4,5,6-tetrahydro-2H-1,2-diazepin-4-ol (A–π–D–π–A) and (E)-7-(4-bromophenyl)-5-(4-nitrophenyl)-2-phenyl-3,4,5,6-tetrahydro-2H-1,2-diazepin-4-ol (A–π–D–π–D), have been investigated using the z-scan technique. NMR, FT-IR, and UV–visible spectral analysis have been performed. The results were compared with density functional theory calculations employing the B3LYP/6-311++G (d, p) basis set. Geometry optimization, frontier molecular analysis, and TD-DFT calculations were conducted in various solvent environments to elucidate solute–solvent interactions. Gaussian 09 software was employed for natural bond orbital analysis, natural population analysis, and molecular electrostatic potential exploration. This comprehensive approach provides insights into the molecular structure and electronic properties of the investigated chromophores, shedding light on their potential applications in nonlinear optics. Normal coordinate analysis using the MOLVIB software has been used to assign the vibrational mode unambiguously. Theoretical second-order hyperpolarizability was computed, and NLO investigations have been employed to determine the second-order hyperpolarizability in both the polar and non-polar solvents. Further, the optical limiting capability was also examined.

Study of Aqueous Solvent effect and Kinetics in Hydrolysis of Butyle Salicylate in Alkaline Medium of Water and DMF

Study of Aqueous Solvent effect and Kinetics in Hydrolysis of Butyle Salicylate in Alkaline Medium of Water and DMF

Molecular spectroscopy, solvent effect, and DFT studies of azithromycin solvate

Azithromycin ethanol solvate monohydrate [C38H72N2O120.5(C2H6O)H2O], abbreviated by AZM-MH-EtOH, was synthesized by slow evaporation method and investigated by powder X-ray diffraction, Raman and infrared (IR) spectroscopy combined with density functional theory (DFT) studies. Electronic and vibrational properties were properly investigated based on a theoretical study of solvation effects, using implicit solvation and solute electron density models. The electronic and vibrational studies were evaluated under aqueous, ethanolic, and vacuum conditions. The electronic structure calculations indicated that the AZM-MH-EtOH is chemically more stable in solvents compared to vacuum condition. Ultraviolet–visible (UV–vis) measurements confirmed the stability of the material in ethanolic medium, due to higher absorbance values compared to the aqueous medium. Vibrational changes were observed in the Raman and IR bands, which have connection with hydrogen bonds. The experimental vibration modes showed better accordance with the predicted modes’ values under solvation effects, but a slight divergence is noticed when we compared to vibration modes obtained in vacuum. Furthermore, the results have revealed a greater affinity profile of AZM-MH-EtOH for water and ethanol solvents compared to theoretical data under vacuum condition.

Interrogating Explicit Solvent Effects on the Mechanism and Site-Selectivity of Aryl Halide Oxidative Addition to L2Pd(0).

We report a study of solvent effects on the rate, selectivity, and mechanism of (hetero)aryl (pseudo)halide oxidative addition to Pd(PCy3)2 as an exemplar of L2Pd(0) species. First, 2-chloro-3-aminopyridine is observed to undergo faster oxidative addition in toluene compared to more polar solvents, which is not consistent with the trend we observe with many other 2-halopyridines. We attribute this to solvent basicity hydrogen bonding between solvent and substrate. Greater hydrogen bond donation from the substrate leads to a more electron-rich aromatic system, and therefore slower oxidative addition. We demonstrate how this affects rate and site-selectivity for hydrogen bond donating substrates. Second, electron-deficient multihalogenated pyridines exhibit improved site-selectivity in polar solvents, which we attribute to different C-X sites undergoing oxidative addition by two different mechanisms. The C-X site that favours the more polar nucleophilic displacement transition state is preferred over the site that favours a less-polar 3-centered transition state. Finally, (hetero)aryl triflates consistently undergo faster oxidative addition in more polar solvents, which we attribute to highly polar nucleophilic displacement transition states. This leads to improved site-selectivity for C-OTf oxidative addition, even in the presence of highly reactive 2-pyridyl halides.

Study of sertraline solubility, solvent effect, and modeling in the aqueous mixtures of dimethyl sulfoxide or diethylene glycol monoethyl ether at several temperatures and its use in the formulation of nanosuspensions

The solubility profile of a weakly water-soluble drug of sertraline (SRT) at the temperature range of 298.2–318.2 K under atmospheric pressure, in the binary aqueous mixtures of dimethyl sulfoxide (DMSO) and diethylene glycol monoethyl ether (DEGMEE) was measured using a shake-flask method. As a result, SRT was discovered to have the maximum solubility in DMSO among investigated solvent systems. The obtained solubility values were correlated by utilizing cosolvency models, including the Jouyban-Acree-van't Hoff and Jouyban-Acree models, and the mean relative deviations were computed in order to evaluate the precision of these equations. Additionally, using the van't Hoff and Gibbs formulas at Thm, the parameters of apparent thermodynamics (Gibbs energy, entropy, and enthalpy) of SRT in the saturated mixtures were calculated. According to these solubility results, SRT nanosuspensions, which had a mean particle size of under 200 nm, were formulated in DMSO and water as a solvent combination. Therapeutic development could be significantly improved by implementing solubilization strategies for enhancing the bioavailability of medicines that are only weakly water-soluble, according to the results of the experimental and statistical assessment of solubility.

A comparative study of solvent effect on propolis extraction by ultrasound-assisted extraction

A comparative study of solvent effect on propolis extraction by ultrasound-assisted extraction

Quantum chemical framework for designing high-performance ladder-shape NLO molecules and study of implicit vs explicit solvent effects on their NLO properties

Researchers in materials science are greatly fascinated by helicene chemistry due to its excellent optical and structural properties. In this work, we introduced symmetrical substitution of donor and acceptor groups on the [7]helicene ([7]HC-1 to [7]HC-5). DFT analysis is used to explore nonlinear optical (NLO) response for designed compounds. For [7]HC-5, the linear isotropic (αiso) and anisotropic polarizability (αaniso) are 31.59 × 10−24 esu and 59.86 × 10−24 esu, respectively. [7]HC-5 has the highest average third-order NLO polarizability (<γ>) of 47.24 × 10−36 esu which is approximately six times greater than that of para-nitroaniline, a well-known prototype NLO molecule. The effect of implicit and explicit solvents on <γ> and αiso of three selected compounds ([7]HC-1, [7]HC-3, and [7]HC-5) is also evaluated. As compared to explicit and gas phase methods, PCM model predicts an overestimation by an increment of ∼ 4-5 times for selected compounds. TD-DFT calculations show a higher transition dipole moment (4.24) and a lower transition energy (3.414 eV) for [7]HC-5. The higher NLO response is explained based on frontier molecular orbitals (FMOs), electron density difference (EDD), and molecular electrostatic potentials (MEPs). There is a red shift for studied compounds based on UV-visible results. The C-N stretching at 1372 cm-1 for [7]HC-5 indicates the presence of -N(CH3)2. Additionally, we studied photovoltaic parameters and found that [7]HC-5 has the maximum open circuit voltage and the lowest dye regeneration of 2.71 eV and 0.06 eV, respectively.

A DFT Study of Mechanism, Diastereoselectivity, and Solvent Effects on the 1,3-Dipolar Cycloaddition Reaction between N-Methyltrichloromethylnitrone and Maleimide Derivatives

A DFT Study of Mechanism, Diastereoselectivity, and Solvent Effects on the 1,3-Dipolar Cycloaddition Reaction between N-Methyltrichloromethylnitrone and Maleimide Derivatives

In-vitro comparative study of solvent effect on antioxidant properties of leaf extracts of Anthocleista djalonensis

This study demonstrated that the extraction solvents play an important role in the extraction of important bioactive compounds with antioxidant properties from the leaves of Anthocleista djalonensis. Anthocleista djalonensis, a plant native to tropical Africa, is believed to have antioxidant properties due to its bioactive composition. The powdered leaves were macerated using local gin, hot distilled water, and analytical ethanol to extract bioactive compounds. The in vitro antioxidant activity of these extracts was assessed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assays, nitric oxide scavenging assay, and hydrogen peroxide scavenging assay. Ascorbic acid was used as a reference. The DPPH and hydrogen peroxide scavenging tests showed concentration-dependent responses. Distilled water had the lowest IC50 value of 0.079 mg/ml and showed the most antioxidant potential in DPPH. Local gin demonstrated significant hydrogen peroxide scavenging ability with an IC50 value of 0.12 mg/ml, surpassing the standard drug. The nitric oxide scavenging assay showed a concentration-dependent increase in both ethanol and local gin extracts. Ethanol and local gin extracts showed maximum antioxidant activity, with ethanol extract showing 22.84% inhibition and local gin extract showing a higher activity of 46.29% inhibition. However, ascorbic acid showed the highest inhibition of nitric oxide production at 57.10%. The study highlights the importance of solvent selection in herbal preparation for optimal health benefits regarding antioxidant activity.

Experimental study of solvent effect on the heat transfer characteristics of 4-[(4-aminophenyl)-(4-imino-1-cyclohexa-2,5-dienylidene) methyl] aniline hydrochloride – A concentration based study

The thermal diffusivity calculations of 4-[(4-aminophenyl)-(4-imino-1-cyclohexa-2,5-dienylidene) methyl] aniline hydrochloride were made for four distinct concentrations of dye dissolved in three solvents. The number of dye aggregates at higher concentrations produce more random collisions. Because of this, heat diffusion will be slower and a reduced thermal diffusivity value was observed. Due to the increased number of dye molecules, cluster formation can also occur at higher concentrations which further reduces the thermal transport through the media. Fourier-transform infrared spectroscopy (FTIR) showed the vibrational bonds of the dye in the three solvents. The dye dissolved in acetone showed higher diffusivity as compared to the other two solvents. Our studies revealed that thermal diffusivity of the dye under study is strongly solvent dependent as well as concentration dependent. The dye under study could be effectively used as insulators or heat sinks with proper choice of concentration and solvent.

Solvent effects on the electrochemical performance of few layered MoS2 electrodes fabricated using FTO substrates

Owing to its exceptional structural, electrical, and optical features, Molybdenum disulphide (MoS2), a two-dimensional (2D) layered material with tuneable bandgap, finds its application in electrochemical supercapacitors for superior energy and power density. Because of their low toxicity and long-term energy storage, the development of MoS2-based supercapacitors is inevitable. The study of solvent effects on the electrochemical performance of a few layered MoS2 using FTO substrates is done for the first time to the best of our knowledge. Exfoliating bulk MoS2 powder in different solvents with variable surface tensions such as Ethanol, Ethylene Glycol (EG), Dimethylformamide (DMF), and Dimethyl Sulfoxide (DMSO) results in the formation of few-layered MoS2 structures. The sample’s structural, optical, and electrochemical behaviours are investigated using x-ray diffraction (XRD), atomic force microscopy (AFM), UV spectroscopy, Fourier transform infrared (FTIR), cyclic-voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). XRD confirms the formation of a 2D MoS2 film with (002) planes and the optical investigation revealed the variation of layer-dependent bandgap with solvents. We observe both faradaic and non-faradaic charge storage mechanisms in the samples and demonstrate a superior pseudocapacitive behaviour for MoS2 in DMF with a maximum specific capacitance of 34.25 F g−1 at a current density of 1 A/g.

Theoretical study of solvent effect on elimination reactions: Hybrid-DFT study, and NBO analysis

In elimination reactions, the arrangement of leaving groups plays a crucial role in facilitating the reaction. On the other hand, equatorial and axial stereoisomers of a compound have a different share of stability. The presence of a solvent plays a different role in the stability of each stereoisomer. From LC-ωPBE and B3LYP methods and Natural Bond Orbital (NBO) interpretation to investigate 3-chloro-8-methyl-8-azabicyclo [3.2.1] octane (1), 3-bromo-8-methyl-8-azabicyclo [3.2.1] octane (2), and 8-methyl-8-azabicyclo [3.2.1] octan-3-yl 4-methylbenzenesulfonate (3), was used. Investigation of thermodynamic parameters showed that equatorial stereoisomers are more stable than axial stereoisomers, and by changing the gas phase to n-hexane and water, the stability of equatorial stereoisomers increased. The stability of the equatorial stereoisomers is the result of the electrostatic model involving dipole-dipole interactions and the combined effects of hyperconjugation interactions and Total Steric Exchange Energy (TSEE). Therefore, it can be expressed that the equatorial stereoisomers of compounds 1-3 show superior performance in the elimination reaction of 1, 4 in the presence of a solvent, and this performance becomes more evident by changing the polarity of the solvent

Elucidating solvent effects on the stability of phenoxyl radicals in monohydric alcohols via electron paramagnetic resonance

Research on solvent effects is an important and long-standing topic, but there still is some room, especially for the special solvent effect of fluoroalcohols. In this work, we investigated the stability of phenoxyl radical in monohydric alcohol solvents through in-situ electron paramagnetic resonance detections. The decay behavior of phenoxyl radical showed a reasonable relationship with the mesoscopic structure of alcohols, characterized by small- and wide-angle X-ray scattering. Moreover, the distinct solvent effects of fluoroalcohols were emphasized, and the significant influence of van der Waals distance in the solvents was suggested. Overall, the stability of phenoxyl radical in alcohols was quantified and correlated with the solvent structures. We believe that the established method for stability study on radicals will encourage solvent effect studies on various organic reactions, and the proposed solvent effects in fluoroalcohols may inspire the development of green solvents in both industrial conversions and organic synthesis.

Gamma-valerolactone-enabled control chemoselective conversion of glucose to 1,6-anhydroglucose over HZSM-5 zeolite

Unraveling chemoselective catalysis in the upgrading of renewable biomass-derived molecules to fine chemicals and bio-fuels is particularly challenging. Here, we report an innovative strategy for the chemocatalytic conversion of glucose into 1,6-anhydroglucose, a high-value platform molecule, in γ-valerolactone (GVL) over HZSM-5 (50) zeolite. In this case, HZSM-5 (50) zeolite exhibits remarkable shape-selective catalytic performance with a high turn-over frequency (TOF) of 201.6 h−1 and a 1,6-anhydroglucose selectivity of 95.3%. Solvent effect study from both experimental and theoretical results suggests the usage of solvent GVL is particularly beneficial for glucose diffusion into the zeolite pore channel, accelerating the isomerization-dehydration process. Kinetic behavior description of glucose transformation to 1,6-anhydroglucose is developed to monitor the process, whereas a synergistic catalytic mechanism is elucidated in detail by density functional theory calculations. Such solvent-induce and shape-selective catalytic system provides a compelling strategy for highly selective production of 1,6-anhydroglucose as a biomass platform molecule.

“Stepwise or concerted or a hybrid mechanism for berberine bridge enzyme?”: A computational mechanistic study by QM-MM and QM methods

Berberine bridge enzyme (BBE) is a plant-based amine oxidase that catalyzes conversion of (S)-reticuline into (S)-scoulerine using flavin as cofactor in a stereospecific way in an alkaloid biosynthesis pathway. Based on the active site enzyme variants, a concerted mechanism was proposed involving hydride transfer, proton transfer, and substrate cyclization processes in a single step. In this mechanism, Glu417 residue acts as the catalytic base which deprotonates the phenolic proton of the substrate while a hydride ion transfers from the substrate to flavin and the substrate cyclizes. However, based on solvent and substrate deuterium kinetic isotope effect studies, it was proposed that the oxidation process occurs in a stepwise fashion in which a hydride ion transfer from substrate to flavin first, then cyclization of the substrate occurs together with the proton transfer process. In this study, we formulated computational models to elucidate the oxidation mechanism of (S)-reticuline into (S)-scoulerine using the crystal structure of enzyme complexed with (S)-reticuline. Both QM and QM-MM calculations revealed that a hybrid of concerted and stepwise mechanisms might be operative during the catalysis. It was found that a concerted hydride-proton transfer processes occurs forming a reactive intermediate which subsequently cyclize without an energy barrier as a decoupled step.

A DFT Study of Solvent and Substituent Effects on the Adsorptive and Photovoltaic Properties of Some Selected Porphyrin Derivatives for DSSC Application.

A DFT/TD-DFT method was employed to study the effects of structural modification and solvent variation on the solubility, adsorptive, and photovoltaic properties of six porphyrins (A-F) obtained by structurally modifying two literature porphyrins A and D. The properties of interest were studied in vacuum, acetonitrile (AcCN), dichloromethane (DCM), dimethyl sulphoxide (DMSO), and ethanol (EtOH) for possible application of the molecules as sensitizers in dye-sensitized solar cells (DSSCs). Electronic absorption properties of the molecules were computed via potential energy surface scan, and thermodynamic data were obtained by DFT calculations in the selected media. Solubility properties of the molecules were mostly enhanced with DMSO as the solvent. The adsorptivity of the molecules onto mesoporous titanium (IV) oxide surface were predicted to be enhanced in the presence of DMSO. Most of the molecules were found to exhibit their highest photovoltaic activity measured in terms of the incidentphoton conversion efficiency (IPCE) in AcCN and DCM, rather than in DMSO due to its high viscosity and the ability to use its oxygen to form the catenating O-Ti4+ bond with the Ti4+ of the TiO2, causing inhibition of electron movement on the semiconductor surface. In general, the computed photovoltaic (PV) properties were found to be enhanced with -CO2H group as the substituent, and in AcCN or DCM as the solvent.

Solvent-Induced Lag Phase during the Formation of Lysozyme Amyloid Fibrils Triggered by Sodium Dodecyl Sulfate: Biophysical Experimental and In Silico Study of Solvent Effects.

Amyloid aggregates arise from either the partial or complete loss of the native protein structure or the inability of proteins to attain their native conformation. These aggregates have been linked to several diseases, including Alzheimer's, Parkinson's, and lysozyme amyloidosis. A comprehensive dataset was recently reported, demonstrating the critical role of the protein's surrounding environment in amyloid formation. In this study, we investigated the formation of lysozyme amyloid fibrils induced by sodium dodecyl sulfate (SDS) and the effect of solvents in the medium. Experimental data obtained through fluorescence spectroscopy revealed a notable lag phase in amyloid formation when acetone solution was present. This finding suggested that the presence of acetone in the reaction medium created an unfavorable microenvironment for amyloid fibril formation and impeded the organization of the denatured protein into the fibril form. The in silico data provided insights into the molecular mechanism of the interaction between acetone molecules and the lysozyme protofibril, once acetone presented the best experimental results. It was observed that the lysozyme protofibril became highly unstable in the presence of acetone, leading to the complete loss of its β-sheet conformation and resulting in an open structure. Furthermore, the solvation layer of the protofibril in acetone solution was significantly reduced compared to that in other solvents, resulting in fewer hydrogen bonds. Consequently, the presence of acetone facilitated the exposure of the hydrophobic portion of the protofibril, precluding the amyloid fibril formation. In summary, our study underscores the pivotal role the surrounding environment plays in influencing amyloid formation.

DFT studies of solvent effect in hydrogen abstraction reactions from different allyl-type monomers with benzoyl radical

Inert allyl-type monomers have been widely documented due to reduce degradation chain transfer. Recently, we and others discovered that the [3 + 2] cyclization reaction process by a photo-driven radical reaction, which can accelerate the polymerization. It was discovered that allyl ether monomers had much higher reactivity than other allyl monomers in the suspension photopolymerization initiated by Type I photoinitiator. Since the hydrogen abstraction reaction (HAR) is the initial step of cyclization, and in order to clarify the influence of solvents effect, three allyl-type monomers were employed, containing “O”, “N” and “S” atom as hydrogen donors. The benzoyl radical obtained from cleavage of photoinitiator was chosen as hydrogen acceptors. We explored the hydrogen abstraction reaction in different solvents (methanol, water and DMSO) by quantum chemistry for geometry and energy. An investigation was undertaken regarding the structural orbital by electrostatic potential (ESP) and topological analysis (ELF and LOL). The findings were also combined with the distortion model and transition state theory. We obtained the molecular interactions used independent gradient method in the Hirshfeld molecular density partition (IGMH). The Eckart’s correction allowed to examine the driving factors of the hydrogen abstraction reaction tunnels and these reactions constant rates are determined in the range of 500–2500 K depending on the modified Arrhenius form in different solvents effect. Our results can provide an answer for the different reactivities.

Structural (monomer and dimer), spectroscopic (FT-IR, FT-Raman, UV–Vis and NMR) and solvent effect (polar and nonpolar) studies of 2‑methoxy-4-vinyl phenol

The structural aspects of 2‑methoxy-4-vinyl phenol (2M4VP) were examined by analyzing both the monomeric and dimeric forms of the highly stable conformer, which were found through a Potential Energy Surface (PES) scan at 170° with energy minima of 0.191 kcal/mol. Experimental and theoretical methods were employed to investigate the spectroscopic properties, including vibrational assignments, electronic transitions, and chemical shifts. Simulating the frontier molecular orbitals (FMO) in different solvents, both polar and non-polar, provides insights into the energy gap (3.9306 eV in chloroform, 3.9059 eV in water, 3.9054 eV in DMSO, and 3.9086 eV in ethanol) and chemical stability. Furthermore, the Natural Bonding Orbitals (NBO), Mulliken population, and Molecular Electrostatic Potential (MESP) surfaces were carried out to get insights into charge distribution, intra-molecular, inter-molecular interactions, and stabilization energies. The majority of the experimental data exhibit a strong correlation with the theoretical values, thereby confirming the highly stable structure of 2M4VP.