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Incorporation of the trimethoxyphenyl group at position 7 of flavin can drastically change the photophysical properties of flavin. We show unique fast singlet 1(π,π*) excited state deactivation pathway through nonadiabatic transition to the 1(n,π*) excited- state, and subsequent deactivation to the ground electronic state (S0), closing the photocycle. This mechanism explains the exceptionally weak fluorescence and the short excited–state lifetime for the flavin trimethoxyphenyl derivative and the lack of excited triplet T1 state formation. Full recovery of flavin in its ground state takes place within a 15 ps time window after photoexcitation in a polar solvent such as acetonitrile. According to quantum chemical calculations, the C(2)-O distance elongates by 0.16 Å in the 1(n,π*) state, with respect to the ground state. Intermediate–state structures are predicted by theoretical ab initio calculations and their dynamics are investigated using broadband vis-NIR time-resolved transient absorption and fluorescence up-conversion techniques. [ABSTRACT FROM AUTHOR]

This article proposes a greener and more efficient method for preparing 9-fluorenone from fluorene via ozone oxidation and the use of micro-nanobubble technology. The effectiveness of ozone micro-nanobubble mass transfer in different polar organic solvents was first studied. Equilibrium concentrations of ozone were higher in alcoholic solvents than in solvents such as ethyl acetate, acetone, dichloromethane, chloroform, and 1,2-dichloroethane, which showed similar equilibrium concentrations of ozone. The variation in hydrogen bonding or dipole–dipole interactions between ozone and solvent molecules caused this change in solubility. Using ethyl acetate as the ideal solvent, with an ozone: fluorene molar ratio of 1.6:1 and reaction duration of 90 min, optimal conditions for ozone oxidation resulted in a 66% yield of 9-fluorenone. We also postulated the chemical mechanism involved in fluorine oxidation by ozone. The presence of hydroxyl radicals during the reaction was confirmed via electron paramagnetic resonance spectra. Indirect ozone oxidation predominated in particular reactions. No requirement of a catalyst and ease of this method makes it well suited for the large-scale manufacturing of 9-fluorenone. [ABSTRACT FROM AUTHOR]

Hibiscetin, a major bioactive ingredient of Hibiscus sabdariffa, exhibits numerous pharmacological actions and five metal-chelating sites. Since flavonoids play a vital role in scavenging or reducing the toxicity of redox-active metal ions, the chelation of Fe2+ cation by the flavonoid Hibiscetin was examined using the DFT method carried out at the M06-2X/6-311+G(d, p)/LANL2DZ level of theory in the aqueous phase. All the complexed species derived from neutral and deprotonated ligand forms were considered. The results show that the oxygen atoms of the di-deprotonated catechol moiety at the C-7 and C-8 positions of Hibiscetin interact best with the Fe2+ ion among the possible chelation sites on Hibiscetin. The stability of the most stable complex, HIB-[7-8] -Fe2+, was validated by Frontier molecular orbital, Natural bond orbital, and natural population reports. The topological analysis indicated the electrostatic interaction between the oxygen atoms of Hibiscetin and the metal ion in the complex. The investigation of the radical scavenging capabilities in gas, water, and benzene media proved the superior antioxidant activity of the most stable complex of Hibiscetin and Fe2+ ion when compared to parent flavonoid. The hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton-loss electron transfer (SPLET) mechanisms were studied, and the HAT mechanism was found to be the most effective radical scavenging mechanism in the gas and non-polar solvent and the SPLET mechanism in the polar solvent. The best site for radical attack is identified to be 4'-OH. [ABSTRACT FROM AUTHOR]

Excitation energy transfer (EET) is a key photoinduced process in biological chromophoric assemblies. Here we investigate the factors which can drive EET into efficient ultrafast sub-ps regimes. We demonstrate how a coherent transport of electronic population could facilitate this in water solvated NADH coenzyme and uncover the role of an intermediate dark charge-transfer state. High temporal resolution ultrafast optical spectroscopy gives a 54±11 fs time constant for the EET process. Nonadiabatic quantum dynamical simulations computed through the time-evolution of multidimensional wavepackets suggest that the population transfer is mediated by photoexcited molecular vibrations due to strong coupling between the electronic states. The polar aqueous solvent environment leads to the active participation of a dark charge transfer state, accelerating the vibronically coherent EET process in favorably stacked conformers and solvent cavities. Our work demonstrates how the interplay of structural and environmental factors leads to diverse pathways for the EET process in flexible heterodimers and provides general insights relevant for coherent EET processes in stacked multichromophoric aggregates like DNA strands. Excitation energy transfer is important for many photoinduced biological processes in systems with multiple chromophores. Here, the authors elucidate this process for the coenzyme NADH using ultrafast spectroscopy and quantum dynamics. [ABSTRACT FROM AUTHOR]

The study was conducted on the impact of thermophysical properties on eflornithine drug solute–solvent interactions in aqueous ethyl acetate and acetone at different concentrations and temperatures. The aim of this study is to enhance the understanding of eflornithine's behavior in different solvents, which is crucial for its effective use in pharmaceutical applications. The density, molar volume, viscometric, and conductometric characteristics of the eflornithine drug solutions (0.025, 0.05, 0.075, 0.1, and 0.125 mol/kg) in acetone and 25% (v/v) aqueous ethyl acetate were measured within a temperature range of 298.15 K–318.15 K. Based on the determined density parameters, the following parameters were assessed: viscosity (η), equivalent molar conductance, limiting apparent molar volume (V0φ), apparent molar volume of transfer (V0φtr), and apparent molar volume (Vφ). The Masson empirical relationship and the viscosity-to-Jones-Dole (JD) equation were used to evaluate the partial molar volume (Vφ), experimental slope (SV), viscosity, and density data. Temperature and concentration were used to determine each parameter. For each set of dilutions, conductometric studies were conducted in both study solvents. The gathered data was analyzed in order to evaluate the ion–solvent interactions. The Walden product Λomηo's positive temperature coefficient values indicate that the drug eflornithine functions as a structural modifier in acetone and aqueous acetyl acetate systems. The structure-making and breaking characteristics of the polar solvents acetone and ethyl acetate were identified. [ABSTRACT FROM AUTHOR]

The single crystals of the title compound (1) were grown from a water solution. The compound crystallizes in the centrosymmetric space group P21/c of the monoclinic system with eight molecules per unit cell. Multiple recrystallizations of the crystals from heavy water gives deuterated analogue 1d. The asymmetric unit of 1 contains two salt molecules. Both independent cations interact with anions via N−H...O hydrogen bonds with R22(8) and R21(6) graphs forming 1:1 salt molecules. Both salt molecules are linked by additional N−H...O and O−H...O hydrogen bonds with a graph R22(9). The oppositely charged components of the crystals, i.e., 1-(diaminomethylene)thiouron-1-ium cations and 2,3-pyridine-dicarboxylate anions, interact each other forming three-dimensional supramolecular hydrogen bonded network. The interactions between the components as well as between the 1:1 salt molecules were analysed using the Hirshfeld surface. The compound was also characterized by vibrational spectroscopy. The vibrational bands were interpreted based on the optimized structure and force field calculations of normal coordinates based on the density functional theory (DFT) with the base set 6-31G(d,p). Isotopic frequency shift and potential energy distribution (PED) were used to assign the bands. The electronic absorption spectra of 1 in the gas phase, as well as in polar and non-polar solvents, were calculated. [ABSTRACT FROM AUTHOR]

We investigate solvent effects in the hydrodeoxygenation of 4-propylguaiacol (4PG, 166 amu), a key lignin-derived monomer, over Ru/C catalyst by combined operando synchrotron photoelectron photoion coincidence (PEPICO) spectroscopy and molecular dynamics simulations. With and without isooctane co-feeding, ring-hydrogenated 2-methoxy-4-propylcyclohexanol (172 amu) is the first product, due to the favorable flat adsorption configuration of 4PG on the catalyst surface. In contrast, tetrahydrofuran (THF)—a polar aprotic solvent that is representative of those used for lignin solubilization and upgrading—strongly coordinates to the catalyst surface at the oxygen atom. This induces a local steric hindrance, blocking the flat adsorption of 4PG more effectively, as it needs more Ru sites than the tilted adsorption configuration revealed by molecular dynamics simulations. Therefore, THF suppresses benzene ring hydrogenation, favoring a demethoxylation route that yields 4-propylphenol (136 amu), followed by dehydroxylation to propylbenzene (120 amu). Solvent selection may provide new avenues for controlling catalytic selectivity. Solvents play a crucial role in catalysis, affecting both activity and selectivity. Here the authors demonstrate how solvent affinity to the catalyst surface influences the reaction pathways of 4-propylguaiacol. [ABSTRACT FROM AUTHOR]

Context: Inspired by the excellent potential application prospects from the precisely controlled attributes displayed by fluorine-substituted-bis(salicylidene)-1,5-diaminonaphthalene (F-BSD) and its derivatives in the domains of photochemistry and photophysics, our present undertaking predominantly focuses on exploring the complexities of photo-induced excited state reactions for F-BSD fluorophores dissolved in solvents with diverse levels of polarity. Our simulations reveal that the excited state intramolecular double proton transfer (ESIDPT) reaction for F-BSD chemosensor can be significantly regulated by solvent polarity-dependent hydrogen bonding interactions and charge recombination induced by photoexcitation, which result from variations in geometries and vertical excitation charge reorganizations. By constructing potential energy surfaces (PESs), we also demonstrate that the stepwise ESIDPT reaction of F-BSD occurs with alternative dual intramolecular hydrogen bonds (O1–H2···N3 or O4–H5···N6). Interestingly, we affirm polar solvents should be conducive to the first-step of ESIDPT process, while nonpolar solvents are in favor of the second step. We sincerely hope solvent polarity-dependent ESIDPT behavior will pave the way for future design of novel luminescent materials. Methods: The molecular geometries were optimized by DFT//TDDFT D3-B3LYP/TZVP theoretical level with IEFPCM solvent model in S0 and S1 states, respectively. This work also explores the energy level of target molecules with the computational vertical absorption spectra by TDDFT. All the simulations were carried out based on Gaussian 16 software. The core-valence bifurcation (CVB) indexes were obtained by using Multiwfn 3.8. Potential energy surfaces were constructed by the DFT//TDDFT D3-B3LYP/TZVP level based on restricted optimization, also the transition state (TS) forms were searched using the same level. [ABSTRACT FROM AUTHOR]

Introducing conjugated Mesoporous Perylene and triphenylamine based Triazine oligomers (M-TPI and D-TPI) for N2 adsorption and fluorescence detection of explosive materials such as Picric acid. This has been synthesized from perylene 3,4,9,10-tetracarboxylic dianhydride with mono and di amino triazine and triphenylamine based compound using a simple polycondensation route. These oligomers are well analysed towards FT-IR, Solid-state NMR (CP-MAS), and HRMS technique. These oligomers have shown good thermal stability up to 280 ˚C from TGA analysis. The mesoporous of these oligomers was recognized from BET N2 adsorption/desorption measurements and showed pore size and volume increased from 1.3 to 2 nm and 0.002–0.08 cm3/g before and after pyrolysis. Photophysical properties (UV–Vis and Fluorescence) reveal that absorption at 350 nm and emission at 513 nm and 505 nm. The optical band gap was found to be 1.7 eV and 1.6 eV and it was well correlated with DFT data. These oligomers dealt with polar solvents and observed a Bathochromic shift of fluorescence emission. In-depth studies of oligomers with various solvent fractions (THF/Water), luminescence intensity was increased leading to aggregation-induced enhanced emission (AIEE), and specifically 60–70% fractioned oligomers showed enormous emission. Further analysis from FE-SEM studies showed that the particles are well aggregated, and the size was measured in the range of 0.67–2.6 µm. AIEE helped to detect explosives (particularly picric acid) and the LOD determined as 1.48 × 10–6 M and 1.196 × 10–7 for M-TPI and D-TPI oligomers. These oligomers underwent practical application on real-water samples, demonstrating excellent recovery rates. These results highlight their efficacy for explosive applications, indicating their potential for significant real-world impact. Hence, the synthesized oligomers are well deserved for gas adsorption and explosive applications. [ABSTRACT FROM AUTHOR]

Nanofilms that can fast permeate solvents and accurately sieve molecules are of significant importance for separation. A promising strategy is to align the inner cavities of macrocycles into the channels within nanofilms, and control the channel size by selecting the macrocycles. However, the channels outside the macrocycles are ignored. Here, we prepare nanofilms with hydrophobic channels (cyclodextrin inner cavity) and hydrophilic channels (cyclodextrin outer space) through interfacial polymerization of azobenzene-4,4′-dicarbonyl dichloride and amino-functionalized β-cyclodextrin. By utilizing the significant geometric changes caused by the photoisomerization of azobenzene, nanofilms with adjustable hydrophilic channel sizes were obtained. Our nanofilms have high permeability to polar and non-polar solvents, and can distinguish molecules with almost the same molecular weight but different shapes. This work expands the development of next-generation nanofilms generated through interfacial polymerization by incorporating rational molecular design. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) derived crosslinked covalent organic nanomaterials (CONs) possessing high specific surface area and abundant surface functional groups are considered to be potential candidates for multimodal chromatographic separations. Typically, the synthesis of CDs and CONs requires harsh reaction conditions and toxic organic solvents, hence, the pursuit of facile and mild preparation strategies is the goal of researchers. In this work, 3-aminopropyltriethoxysilane and D-glucose were used as nitrogen and carbon sources, respectively, to prepare amino-CDs (AmCDs) by rapid low-temperature polymerization rather than the common high-temperature and high-pressure reaction. Then, surface functionalization of the aminated silica gel was carried out in a deep eutectic solvent by using hydrophilic AmCDs and 1,3,5-triformylbenzene (TFB) as the functional monomers. Consequently, a novel N-rich CDs derived CON surface-functionalized silica gel (AmCDs-CON@SiO2) was obtained under mild reaction conditions. The combination of AmCDs and TFB created an ideal CON based chromatographic stationary phase. The incorporation of TFB not only contributed to the successful construction of a crosslinked CON, but also enhanced the interaction forces. The developed AmCDs-CON@SiO2 has a great potential for versatile applications in liquid chromatography. This study proposes a simple stationary phase preparation strategy by the surface modification of silica gel with CDs-based CON. Moreover, this study verified the application potential of CDs derived CON in chromatographic separation. This not only promotes the development of CDs in the field of liquid chromatographic stationary phase, but also provides some reference value for the wide application of cross-linked CON. [ABSTRACT FROM AUTHOR]

Although cellulosic materials have been used as stabilizing agents for oil-in-water emulsions since the 1980s, their properties and the underlying mechanism are not universal regardless of the dispersed phase or of the treatments on cellulose. One case of unconventional organic phase is acetic acid-containing chloroform, which is known to be a good solvent system for the preservation of dithizone. In turn, dithizone is a long-known chromogenic reagent for the colorimetric detection of HgCl2. However, its usefulness is limited by its fast degradation in polar solvents. For instance, its dissolution in ethanol and the subsequent impregnation of paper strips allowed to quantify aqueous HgCl2 reliably and quickly (5.4 – 27 mg L–1), but only if they were used along the first 24 h after dip coating. Furthermore, those strips could not be used for sublimated HgCl2. The dithizone/chloroform-in-water emulsions presented in this work overcame these limitations. We opted for oxalic acid-treated cellulose nanofibers (ox-CNFs) as stabilizer, aiming at a proper balance between amphiphilic character and electrostatic repulsion. In this sense, ox-CNFs attained good gel-forming ability with a low content of carboxylate groups. The minimum ox-CNF concentration required was 0.35 wt%, regardless of the proportion of chloroform. This consistency implied yield stress values above 0.7 Pa. Nanocellulose also provided film-forming capabilities, which were exploited to produce visually responsive dipsticks and membranes. While quantification and reproducibility were hampered by the increase in the complexity of the system, dithizone/ox-CNF films were still a valid option for HgCl2 detection, outperforming solution coating in terms of stability, blank signal, and selectivity. [ABSTRACT FROM AUTHOR]

Synsepalum dulcificum (Miracle fruit) is a tropical plant in West and Central Africa, which has been historically used for treating diarrhea in humans and animals. Pharmacological research has shown that the leaves of the plant possess anti-hyperlipidemia activity. However, its anti-hyperlipidemic components have not been reported. In this study, the leaves of S. dulcificum were extracted using 95% ethanol and the extract was fractionated using different polar solvents. The anti-hyperlipidemia activity of the extract and fractions were evaluated using the zebrafish model. The results showed that the ethyl acetate (EA) fraction displayed the best anti-hyperlipidemic effect. A comparison of the high-performance liquid chromatography equipped with diode array detector (HPLC-DAD) profiles of the ethanol extract and different fractions at 350 nm indicated that a peak at 37.4 min has the highest intensity in the EA part, relatively. Then the chemical constituents of the extract and the active fraction were extensively identified using UPLC-Q-Exactive-Orbitrap-MS/MS, showing the main peak was quercitrin and other components in the EA part mainly included quercitrin analogs. Furthermore, the quercitrin was isolated from the plant and its contents in the extract and fractions were determined using high-performance liquid chromatography with ultraviolet detector (HPLC-UV) method. The quantitative results showed that the content of quercitrin in the EA fraction was 10.04% (w/w). Further pharmacological study indicated that quercitrin also possessed potent anti-hyperlipidemia activity (improvement rates of liver fat and total cholesterol were 75.6% and 92.5% at 40 μg/mL, respectively). Besides, quercitrin showed little toxicity to zebrafish embryos. [ABSTRACT FROM AUTHOR]

It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional (3D) hierarchical nanostructures and constructing oxygen vacancies (VOs). However, controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing VOs in photocatalysts remains a challenge. Herein, we reported an ethylene glycol (EG) mediated approach to craft 3D hydrangea-structure Bi2MoO6 with VOs for efficient photocatalytic degradation of tetracycline. Through manipulating the EG concentration during the fabrication process, the influence of EG concentration on the Bi2MoO6 structure was systematically investigated. EG could promote the self-assembly of Bi2MoO6 nanosheets to form a 3D hierarchical structure. Compared with 2D nanoplates, 3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi2MoO6. In addition, the reduction effect of EG on metallic oxide enabled the generation of VOs in Bi2MoO6. The VOs adjusted the electronic structure of Bi2MoO6, which not only enhanced the light harvesting, but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species (·O2− and ·OH) for the efficient tetracycline decomposition. 3D Bi2MoO6 hydrangea with VOs achieved a 79.4% removal efficiency of tetracycline after 75 min. This work provides a simple yet robust EG-mediated strategy, which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures, but also crafts tunable VOs for highly efficient photocatalysis. [ABSTRACT FROM AUTHOR]

For decades, it was considered all but impossible to perform Stark spectroscopy on molecules in a liquid solution, because their concomitant orientation to the applied electric field results in overwhelming background signals. A way out was to immobilize the solute molecules by freezing the solvent. While mitigating solute orientation, freezing removes the possibility to study molecules in liquid environments at ambient conditions. Here we demonstrate time-resolved THz Stark spectroscopy, utilizing intense single-cycle terahertz pulses as electric field source. At THz frequencies, solute molecules have no time to orient their dipole moments. Hence, dynamic Stark spectroscopy on the time scales of molecular vibrations or rotations in both non-polar and polar solvents at arbitrary temperatures is now possible. We verify THz Stark spectroscopy for two judiciously selected molecular systems and compare the results to conventional Stark spectroscopy and first principle calculations. Stark spectroscopy of molecules in liquid solutions was once challenging due to orientation effects, solved by freezing but limiting ambient studies. Now, THz Stark spectroscopy with intense terahertz pulses enables dynamic analysis of molecules in both non-polar and polar solvents at any temperature, advancing conventional methods. [ABSTRACT FROM AUTHOR]

Sample preparation is a constantly evolving step in the measurement process with a positive effect on its performance. Its evolution has been marked by an underlying environmental commitment, with simplification, miniaturization, and automation being three of its driving forces. This trends article deepens how the sample preparation can go sustainable through the efficient design of new sorptive materials, either liquid or solid. This objective can be achieved by using natural and/or biodegradable materials as precursors of the functional sorptive phases and by designing materials that simplify the procedures (thus reducing the energy or resources required). Although environmental performance is a crucial aspect of a new material, its applicability is what really defines its incorporation into the sample preparation toolbox. For this reason, their characteristics and more relevant applications will be briefly presented to conclude with the tendency of their use in the very near future. [ABSTRACT FROM AUTHOR]

New polyfunctional compounds of the pinane series, 2-carboxy-3-thioacetate, 2-carboxy-3-sulfonyl chloride, and 2-carboxy-3-sulfonic acid that are promising intermediate products in organic synthesis, were synthesized for the first time by the reaction of S-(1S,2R,3S,5R)-(6,6-dimethyl-2-formylnorpinan-3-yl) thio-acetate with chlorine dioxide. The major reaction pathway in nonpolar solvents involves oxidation of the aldehyde group to carboxy, whereas oxidation of the sulfur atom, followed by deacetylation, occurs in highly polar solvents. The effect of VO(acac)2 as catalyst on the reaction chemoselectivity in weakly polar diethyl ether was revealed. [ABSTRACT FROM AUTHOR]

FDM, being the most popular AM technology, has a wide user base across the globe. The process makes use of a layer-by-layer approach, causing a staircase effect on the material's printed surface. Though it affects several mechanical properties, its effect on surface integrity is highly detrimental and needs to be addressed. Chemical vapour dip and immersion techniques can provide a rapid solution using solvents. The solvents employed in the current study were the polar solvents- acetone and ethyl acetate, the mid-polar solvent- tetrahydrofuran (THF), and the non-polar solvents- chloroform and dichloromethane (DCM). The superior surface finish obtained during the post processing of 3D printed parts was having mean roughness value (Ra) of 0.67 µm, originally 11.42 µm. It was obtained when experimentation was carried out with the chemical vapour technique using THF. The optimum surface finish was readily achieved with mid- and non-polar solvents, whereas the polar solvents were slow to react with the surface of the PLA. A number of variables, including the solvent's polarity, boiling point, vapour pressure, and water miscibility, have an impact on the final surface's appearance and strength. During vapour treatment, the tensile strength of the 3D printed parts got reduced between 11.6% (THF) to 43.78% (DCM). On the other hand, the chemical immersion technique has a even more impact on the material's strength and hardness. It reduces hardness to the maximum of 44.41% (THF), whereas the vapour evaporation technique reduces hardness by only up to 14.64% (chloroform). [ABSTRACT FROM AUTHOR]

The isoniazid-vanillin hybrid (IVH), a Schiff base compound is synthesized and its vibrational spectral properties, structural, linear and third-order nonlinear optical (TNLO) characteristics are studied. IVH is examined by 1H and 13C NMR, FT-IR and mass spectroscopic techniques. Solvent dependent TNLO properties are studied by Z–scan technique for which a 5 mW power CW diode laser with 650 nm wavelength is used. The order of nonlinear refractive index (n2) and nonlinear absorption coefficient (β) is measured to be 10−7 cm2/W and 10−3 cm/W, respectively. The sample exhibits both positive and negative nonlinear absorption coefficient owing to the phenomenon of saturable and reverse saturable absorption, as well as negative nonlinear index of refraction as a result of self-defocusing. Self-defocusing is the result of thermal nonlinearity owing to the continuous absorption of light source. The real and imaginary component of the TNLO susceptibility of the sample is found to be the order of 10−7 esu. The order of TNLO susceptibility (χ(3)) of IVH in polar solvents is measured to be 10−7 esu. The effect of solvent spectral features on χ(3) is also discussed. The results show that, the organic compound IVH is a promising candidate for applications in nonlinear optics. [ABSTRACT FROM AUTHOR]

High β-phase polyvinylidene fluoride (PVDF) thin films have excellent piezoelectricity and flexibility. They are widely used in wearable devices, hydroacoustic ultrasound, and energy harvesting. The preparation of PVDF thin films by near-electric-field 3D printing can be customized in shape, and the high β-phase can be obtained without stretching or polarization. In this work, the effects of polar solvent, printing voltage, and PVDF molecules on the β-phase content of PVDF thin films prepared by near-electric-field 3D printing were analyzed. The results show that the polarity of the solvent affects the molecular chain conformation of PVDF, which is favorable for the generation of the β-phase. With the increase of solvent polarity, the β-phase content in PVDF films increased from 21.40% to 26.31%. The mutual motion of the collecting plate and the needle will produce stronger mechanical traction on the PVDF fibers, which is due to the smaller diameter of the PVDF fibers caused by the high printing voltage. The joint action of this tensile force and the strong electric field attraction promotes the β-phase transition. When the printing voltage is 8 kV, the F(β) value of PVDF film is increased by 47.37% over that without applied voltage. In addition, the interaction of small and large PVDF molecular weight will also result in mechanical deformation of the molecular chain and promote the β-phase transition. [ABSTRACT FROM AUTHOR]

Metal nanoparticle@porous material composites have attracted increasing attention due to their excellent synergistic catalytic performance. However, it is a challenge to introduce metal nanoparticles into cavities of porous materials without agglomeration on the exterior. Despite the progress achieved, a universal approach that can integrate different kinds of metal nanoparticles and porous materials is still highly desirable. Here we report a facile and general approach to fabricating metal nanoparticle@porous materials by microwave-triggered selective heating. The microwave can pass through the non-polar solvent and act on the polar solvent in the porous materials, causing the polar solvent to be heated, vaporized, and away from the pores of porous materials. The local void produced by the escape of polar solvent facilitates non-polar solvent containing metallic precursor to be dragged into the narrow pores, followed by further reduction, resulting in the complete encapsulation of nanoparticles. A series of metal nanoparticles@porous materials, ranging from metal-organic frameworks (MOFs) to zeolites, are successfully prepared by this method and show excellent size selectivity in catalytic reactions. [ABSTRACT FROM AUTHOR]

Efficiently capturing radioactive methyl iodide (CH3I), present at low concentrations in the high-temperature off-gas of nuclear facilities, poses a significant challenge. Here we present two strategies for CH3I adsorption at elevated temperatures using a unified azolate-based metal-organic framework, MFU-4l. The primary strategy leverages counter anions in MFU-4l as nucleophiles, engaging in metathesis reactions with CH3I. The results uncover a direct positive correlation between CH3I breakthrough uptakes and the nucleophilicity of the counter anions. Notably, the optimal variant featuring SCN- as the counter anion achieves a CH3I capacity of 0.41 g g−1 at 150 °C under 0.01 bar, surpassing all previously reported adsorbents evaluated under identical conditions. Moreover, this capacity can be easily restored through ion exchange. The secondary strategy incorporates coordinatively unsaturated Cu(I) sites into MFU-4l, enabling non-dissociative chemisorption for CH3I at 150 °C. This modified adsorbent outperforms traditional materials and can be regenerated with polar organic solvents. Beyond achieving a high CH3I adsorption capacity, our study offers profound insights into CH3I capture strategies viable for practically relevant high-temperature scenarios. Efficient capture of methyl iodide (CH3I) from high-temperature nuclear off-gas is quite challenging. Here, the authors present two innovative and efficient strategies to adsorb CH3I at high temperatures in an azolate-based metal-organic framework. [ABSTRACT FROM AUTHOR]

In the high friction limit, the initial works of the diffusion–reaction system utilising the one-dimensional Smoluchowski equation have been largely explored by a perfect trap term and a relevant system potential. The fast electronic relaxation process in a polar solvent can best be understood using the perfect sink model. The exact dynamics, however, are only available when the trap is placed in the harmonic potential centre. To solve the model equation for the arbitrary placement of the trap, here we have proposed a fresh, slightly uncommon approach. Additionally, we gave exact results to a recently investigated linear confined-type potential for the perfect trap placed arbitrarily. When the trap is positioned at an uphill location relative to the initial distribution, notable non-monotonic effects of the decay properties have been identified for the variation of potential strength. [ABSTRACT FROM AUTHOR]

Due to the high oil content, rubber seed oil (RSO) has the potential to be used as a raw material in biodiesel manufacturing. The present study was aimed at oil extraction on rubber seed composed of 47–51% kernel by seed weight. The effects of extraction time (0.75–120 h), particle size (0.14 ± 0.047 µm, 0.35 ± 0.003 µm, and 0.68 ± 0.1 µm), dryness, the type of solvent (polar and non-polar), and different methods of extraction were studied in this work. RSO extracted with a non-polar solvent, hexane, yielded 46.8 ± 0.92%, while a polar solvent, methanol, yielded a lower yield (28.5 ± 0.36%). The average sample size weakly influenced the extract yield with a weak correlation (r = − 0.213), but a strong negative relationship was found between the extract's yield and the samples' moisture (r = − 0.974). Therefore, this study used an Adaptive Neuro-Fuzzy Inference System (ANFIS) model to evaluate the prediction of the extract yield performance versus particle size and moisture of the samples. Results confirm consistency between the compositional results of the unsaturated fatty acids obtained by the gas chromatography–mass spectrometry (GC–MS) method (linoleic [39.72%], oleic [23.02%], linolenic [11.91%], and saturated [25.32%]). RSO's high extraction yield as a low-cost feedstock offers a cost-effective and ecologically acceptable alternative to conventional feedstock for biodiesel synthesis. [ABSTRACT FROM AUTHOR]

Context: One of the prevalent methods for evaluating separation performance is to predict the interactions of solvent and solute molecules. The infinite dilution activity coefficient, Gibbs free energy, and sigma profiles provided insights into the solubilization of a solute and revealed the intensity of the solution's molecular interactions. The effective thermodynamic tools (infinite dilution activity coefficient, Gibbs free energy) were evaluated for predicting the efficiency of 18 polar and non-polar organic solvents in rubber seed oil (RSO) extraction. An infinite dilution activity coefficient was computed to evaluate the solubility of the rubber seed oil model compound (linoleic acid) in the organic solvents. Gibbs free energy was evaluated to show the energy change associated with the molecules mixing process and forecast the miscibility of linoleic acid molecules in the solvents. Moreover, the study examined the sigma profiles and sigma surfaces of organic solvents and linoleic acid to acquire a deeper insight into their similarities and how they interact molecularly. According to the computational prediction and experimental verification, the thermodynamic properties of Gibbs free energy and activity coefficient proved to be highly effective tools for screening polar and moderately polar solvents, predicting the molecular interactions with solute. Whereas the sigma profile and sigma surface were found to be the most efficient tools for evaluating the efficacy of non-polar solvents. Solvents with moderate polarity, such as tetrahydrofuran and diethyl ether, as well as non-polar solvents like pentane, heptane, and n-hexane, proved to be effective and favorable for oil extraction, resulting in the highest oil yields of approximately 27.0%. Overall, the COSMO-RS method demonstrates its utility in estimating the solubility of RSO in organic solvents, enabling early identification of the most effective solvent. Methods: The initial geometry optimization of every component was conducted through density functional theory (DFT) using TmoleX software. A single-point density functional theory (DFT) computation using Becke Perdew 86 (BP86) and the Triple-Zeta Valence Potential (TZVPD) was performed to produce.cosmo files. COSMO-RS calculations were performed by applying the parameterization file BP_TZVPD_FINE_19.ctd using COSMOthermX software. The practical extraction of oil from plant seeds was performed using a sonicator bath to verify the accuracy of the COSMO-RS predictions. [ABSTRACT FROM AUTHOR]

Variable temperature NMR spectroscopic measurements on (S)-warfarin [open-form: 3-(1′-phenyl-3′-oxobut-1′-yl)-4-hydroxycoumarin] in CDCl3, CD3OD and d6-DMSO generally showed tautomeric compositions in the order trans (2S,4S) coumarin hemiketal > cis (2R,4S) coumarin hemiketal > open (S) coumarin enol in slow dynamic equilibrium over temperature ranges rising modestly from ambient. A computational (DFT-M06-2X) examination of the lower energy tautomers including coumarin and chromone open and cyclic forms (gas phase, chloroform or DMSO fields) was consistent with the general solution compositions. The crystal and molecular structures for model compounds of the major solution tautomers are reported: (2S,4S)-warfarin methyl ketal [orthorhombic, P212121], (2R,4S)-warfarin methyl ketal [orthorhombic, P212121], (rac)-warfarin-4-methyl ether [monoclinic, P21/n], and the open chromone (S)-warfarin-2-methyl ether [monoclinic, P21, Z = 8]. A combination of direct integration and line-fitting methods were used to determine solution (S)-warfarin tautomer compositions. As temperatures were increased, the concentrations of the open coumarin form increased at the expense of the cyclic hemiketals. Equilibrium constants were used to determine the standard free-energy differences for the two open-cyclic equilibria (trans hemiketal ⇌ open, open ⇌ cis hemiketal, respectively) in three solvents: CDCl3 [+ 3.7(4), − 2.8(6) kJ/mol], CD3OD [+ 7.6(16), − 4.7(9) k/mol], d6-DMSO [+ 3.5(7), − 1.1(2) kJ/mol]. Standard enthalpy and entropy differences were also determined from van't Hoff analysis. Rates of the respective reactions were estimated from line-widths for the cyclic hemiketals and solution equilibrium compositions for each species. Eyring analysis gave ΔG‡, ΔH‡, and ΔS‡, respectively, for the forward and reverse reactions of coumarin trans hemiketal ⇌ open-form and for the open-form ⇌ cis hemiketal. Negative entropic contributions to the observed transition state energies were consistent with solvent or solute ordering in the prototropic reactions. Open-form NMR signals were broader than could be accounted for by the open-cyclic equilibria alone, increasingly so in polar and protic solvents and with rising temperatures. While a conformational equilibrium may operate, an increasingly faster intermediate dynamic equilibrium between open coumarin-chromone tautomers may be a more likely explanation. Structures of methylated warfarin tautomers and computational models enabled assignment of overlapping warfarin tautomeric NMR spectra and through variable temperature analysis, provided the thermodynamics of the tautomeric equilibria in three solvents. [ABSTRACT FROM AUTHOR]

Background: Multidrug resistance-associated protein 1 (MRP1), an energy-dependent efflux pump, is expressed widely in various tissues and contributes to many physiological and pathophysiological processes. 6-Bromo-7-[11C]methylpurine ([11C]7m6BP) is expected to be useful for the assessment of MRP1 activity in the human brain and lungs. However, the radiochemical yield (RCY) in the synthesis of [11C]7m6BP was low, limiting its clinical application, because the methylation of the precursor with [11C]CH3I provided primarily the undesired isomer, 6-bromo-9-[11C]methylpurine ([11C]9m6BP). To increase the RCY of [11C]7m6BP, we investigated conditions for improving the [11C]7m6BP/[11C]9m6BP selectivity of the methylation reaction. Results: [11C]7m6BP was manually synthesized via the methylation of 6-bromopurine with [11C]CH3I in various solvents and at different temperatures in the presence of potassium carbonate for 5 min. Several less polar solvents, including tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), and ethyl acetate (AcOEt) improved the [11C]7m6BP/[11C]9m6BP selectivity from 1:1 to 2:1, compared with the conventionally used solvents for the alkylation of 6-halopurines, acetone, acetonitrile, and N,N-dimethylformamide. However, a higher temperature (140 °C or 180 °C) was needed to progress the 11C-methylation in the less polar solvents, and the manual conditions could not be directly translated to an automated synthesis. [11C]Methyl triflate ([11C]CH3OTf) was thus used as a methylating agent to increase the conversion at a lower temperature. The 11C-methylation using [11C]CH3OTf at 100 °C proceeded efficiently in THF, 2-MeTHF, and AcOEt with maintenance of the improved selectivity. Starting from 28 to 34 GBq [11C]CO2, [11C]7m6BP was produced with 2.3–2.6 GBq for THF, 2.7–3.3 GBq for AcOEt, and 2.8–3.9 GBq for 2-MeTHF at approximately 30 min after the end of bombardment (n = 3 per solvent). The isolated RCYs (decay corrected) for THF, 2-MeTHF, and AcOEt were 24–28%, 29–35%, and 22–31% (n = 3), respectively. Conclusions: The use of THF, 2-MeTHF, and AcOEt improved the [11C]7m6BP/[11C]9m6BP selectivity in the methylation reaction, and the improved method provided [11C]7m6BP with sufficient radioactivity for clinical use. [ABSTRACT FROM AUTHOR]

Third-order nonlinear optical (TNLO) features of acid black 32 (AB 32); an azo dye is examined by sensitive Z-scan method. Various polar solvents such as methanol, acetone, ethanol, water, DMF and DMSO are used to dissolve the dye sample with 0.01 mM concentration. A continuous wave diode laser operating at 650 nm wavelength is used to study the TNLO properties of AB 32 dye. The influence of solvent spectral characteristics on linear absorption coefficient (β) and TNLO properties of AB 32 dye is studied and multi-parameter scale known as Kamlet-About-Taft is used to analyze the solvent characteristics on solute molecule. The nonlinear refractive index (n2) and nonlinear absorption coefficient (β) of AB 32 dye are calculated to be the order of 10−7 cm2/W and 10−2 cm/W, respectively. The open aperture curve of AB 32 dye is displayed both positive and negative nonlinear absorption coefficient due to saturable and reverse saturable absorption, as well as negative value of n2 as a result of self-defocusing. The results projected that AB 32 dye is a suitable material for future NLO applications in photonics and optoelectronics. [ABSTRACT FROM AUTHOR]

Since sericite has no ion exchange capacity and no expandability in water, it can hardly be intercalated, which substantially degrades the thermal-insolating performance of sericite/polystyrene composite materials. In this paper, the surface modification technique of sericite was optimized. Moreover, the coupling agent and sericite were dissolved in a polar organic solvent for the first time, so that they can fully react in the organic solvent, which significantly increase the cation exchange capabilities of sericite. After surface modification, the sericite exhibits layered morphology, and the coupling agent spots can be clearly observed on the surface. The contact angle of the modified sericite increases from 0° to 90°, thus ensuring the hydrophobic effect. Therefore, the expandable polystyrene (EPS) with uniform particles can be prepared by adding the modified sericite into the styrene suspension polymerization, which guarantees a 15% reduction in thermal conductivity of EPS. Our investigation on the surface modification of sericite is expected to shed more light on the fabrication of clay/polymer composite system, and the EPS may potentially be applied as an ideal thermal insulation material. [ABSTRACT FROM AUTHOR]

This paper focuses the study of nonlinear absorption (NLA) features of anthraquinone dye namely, acid blue 129 with different polar solvents including ethanol, methanol, acetone, 1-proponal and DMSO. The acid blue 129 dye in polar solvents is characterized by UV–Visible absorption and fluorescence study. The NLA measurements of acid blue 129 dye is examined via open aperture (OA) Z-scan method employing at 650 nm wavelength. The OA Z-scan curve of the experimental dye exhibits both saturable absorption (SA) and reveres saturable absorption (RSA) signature, which results from negative and positive NLA coefficient (β). The order of ground and excited state absorption cross-section is measured to be 10˗22 m2 and 10˗18 m2, respectively and proved the existence of RSA in acid blue 129 dye. The order of NLA coefficient and imaginary component of the third-order nonlinear susceptibility of acid blue 129 dye in polar solvents is calculated to be 10˗3 cm/W and 10˗5 esu, respectively. The multi-parameter scale viz., Kamlet-Abboud-Taft is used to measure the influence of solvent parameters on solute molecule. The results from the experiments suggest that the acid blue 129 is a suitable candidate for nonlinear optical (NLO) applications. [ABSTRACT FROM AUTHOR]

The effects of hybrid functionals and solvents (nonpolar, polar aprotic, and polar protic) on the results of calculating the photochemical transformations of unsubstituted spirooxazine (TMINSO) in solution were analyzed. A preliminary selection of functionals showed that the predominant S0→S1 transition observed in the experiment for the closed form gives BMK, CAM-B3LYP, LC-ωHPBE, M052X, M062X, M08HX, M11, MN15, SOGGA11X, ωB97, ωB97X, and ωB97XD functionals in each of the three solvents considered (cyclohexane, acetonitrile, methanol). The functionals that did not break the Cspiro-O bond upon TMINSO excitation (LC-ωHPBE, M11, and SOGGA11X in all solvents considered, and ωB97 in the methanol) nonetheless weakened it. Most of the functionals that provided the photoinduced breaking of the Cspiro-O bond in all three solvents under consideration gave excited intermediate X* forms in which the indoline and naphthoxazine units are approximately perpendicular to each other. The exceptions were M052X and ωB97XD in both polar solvents. The outcome of X*→X relaxation is determined by the X* conformation, which, in turn, is the interplay of the used functional and the solvent. For intense photobleaching in a nonpolar solvent, the excitation of the planar merocyanine form must be accompanied by its twisting into the X* form, causing the Cspiro and O atoms to approach each other, which, in turn, makes it possible to recover the Cspiro-O bond. In polar solvents, TMINSO photobleaching, on the contrary, is weak, which corresponds to the preservation of the planar excited open structure. Therefore, functionals giving both of these effects (M052X and ωB97XD) are recommended for modeling the phototransformations of spirooxazine in polar and nonpolar solvents. The possibility of recovering the Cspiro-O bond does not depend directly on the distance between these atoms but on the electron densities on them and the conformation of the linker connecting the aromatic systems in the X form. Three solvating methanol molecules for most of the used functionals stabilize the closed form of TMINSO. Preservation of the planar MC structure during its excitation in the composition of the solvated complex gives only the M052X functional, so it is recommended for modeling the excitation of spirooxazine in methanol. The effect of excitation on the H-bonds of spirooxazine with methanol in the solvated complex was also analyzed. [ABSTRACT FROM AUTHOR]

Two Al-MOFs, i.e., MIL-53 (Al) and (NH2)-MIL-53 (Al) have been synthesized using aluminium nitrate as metal ligands and 1,4 benzene dicarboxylic acid, amino 1,4 benzene dicarboxylic acid as organic linkers in aqueous medium at room temperature, respectively. Both Al-MOFs have been confirmed through different microscopy and spectroscopy tools. Afterwards, the optical properties of Al-MOFs have been confirmed in polar and non-polar solvents using photoluminescence spectroscopy. Finally, both Al-MOFs have been explored for optical nitrobenzene (NB) sensing. Interestingly, we have found excellent optical ability of NH2-MIL-53 (Al) over MIL-53 (Al) due to structural π–π* transitions. The photo-induced electron transfer mechanism has been found during the MOF–analyte interaction. Importantly, we confirmed that NH2-MIL-53 (Al) is an excellent sensing material for NB with a 0.28 ppb limit of detection over MIL-53 (Al). [ABSTRACT FROM AUTHOR]

Low power laser induced third-order nonlinear optical (TNLO) parameters of Schiff base molecule (E)-N'-(4-(dimethylamino)benzylidene) isonicotinohydrazide (ISB), is synthesized and characterised by UV-Visible, FT-IR, 1H NMR, 13C NMR and mass spectroscopy techniques. The effect of polar solvents on linear features and TNLO features of ISB are examined. TNLO properties of ISB are studied via low power Z–scan method, using a diode laser working at 650 nm wavelength. Self-defocusing, saturable absorption (SA) and reverse saturable absorption (RSA) based optical nonlinearities are observed. The order of nonlinear index of refraction (n2) and nonlinear coefficient of absorption (β) of ISB is found to be10−7 cm2/W and 10−3 cm/W, respectively. The β of ISB has switchover from SA to RSA by increasing the solvent polarizability. Furthermore, the TNLO susceptibility (χ(3)) of ISB increases with increase in solvent dipole moment. Due to its exceptional optical features; ISB serves as an ideal nonlinear optical material for photonics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

Quantum-chemical simulations of the transformation of 2,2-di(nitrophenyl)-1,1,1-trichloroethane into 4,4′-dinitrobenzophenone during the interaction with nitrite ion in aprotic polar solvents have been performed. It has been established that the dehydrochlorination reaction of 2,2-di(nitrophenyl)-1,1,1-trichloroethane proceeds via a synchronous E2H mechanism. A possible scheme for subsequent formation of 4,4′-dinitrobenzophenone has been proposed. For each stage of the multistage process, spatial structures have been simulated and the energy parameters of pre-reaction, activated, and post-reaction complexes have been calculated. [ABSTRACT FROM AUTHOR]

The absorption and fluorescence emission spectra of terpyridine incorporating pyrene moiety (Tpy-pyr) have been recorded in extensive variety of solvents having different polarities. The effect of the solvent on the spectral characteristics are examined. It is shown that Tpy-pyr exhibit positive solvatochromism, large Stokes shift values in polar solvents, and fluorescence in the long wavelength region of the visible range. A linear increasing trend with Stokes shift indicates the presence of Tpy-pyr - solvent interaction. The acquired results could be attributed to the formation of excited states with intramolecular charge transfer. The fluorescence quantum yield was drastically reduced in polar protic solvents and the formation of the twisted states with charge transfer was proposed. Both ground and excited state dipole moments (µg and µe) were determined experimentally by Lippert–Mataga, Reichardt, Bilot-Kawski, Bakhshiev and Kawski-Chamma-Viallet solvatochromic methods analyzed on the base of the microscopic solvent polarity functions. The µg and µe dipole moment of Tpy-pyr estimated from density functional theory (DFT) and those determined experimentally from solvatochromic methods are compared and the results are discussed. [ABSTRACT FROM AUTHOR]

Flexible and aromatic photofunctional system (FLAP) is composed of flapping rigid aromatic wings fused with a flexible 8π ring at the center such as cyclooctatetraene (COT). A series of FLAP have been actively studied for the interesting dynamic behaviors. Here, we synthesized a new flapping molecule bearing naphtho-perylenebisimide wings (NPBI-FLAP), in which two perylene units are arranged side by side. As a reference compound, we also prepared COT-fused NPBI (NPBI-COT) that contains only single perylene unit. In both compounds, inherent strong fluorescence of the NPBI moiety is almost quenched and the FL lifetime becomes much shortened in highly polar solvents (acetone and DMF). Through the analyses of environment-sensitive fluorescence, electrochemical reduction/oxidation, and femtosecond transient absorption, the fluorescence quenching behavior was attributed to rapid symmetry-breaking charge separation (SB-CS) for NPBI-FLAP and to intramolecular charge transfer (ICT) for NPBI-COT. Most of the excited species of these compounds decay with the bent geometry, which is in contrast with the excited-state planarization behavior of a previously reported COT-fused peryleneimides with the double-headed arrangement of the perylene moieties. These results indicate that changing the fusion manners between COT and other π skeletons offers new functional molecules with distinct dynamics. [ABSTRACT FROM AUTHOR]

The spectrophotometric studies of vanadylporphyrin complexes isolated from the oil of the Severnoe Buzachi field with absorption maxima at 534 and 573 nm showed that the dominant compounds were etioporphyrins (ETIOs) and deoxophylloerythro-etioporphyrins (DPEPs), and that extraction with N,N-dimethylformamide allows extraction of vanadylporphyrin complexes from oil without destroying their structure. The ETIO/DPEP ratio of vanadylporphyrins was 1.14–2.17. The IR spectra of the isolated vanadylporphyrin fractions indicated that the content of free porphyrins was extremely low judging by the presence of deformation and out-of-plane vibrations of the NH group in the ranges 3250–3400 and 960–980 cm–1. This suggests that the extraction method for isolating vanadylporphyrins does not lead to their demetallization. The EPR spectral data confirmed the high concentration and purity of vanadylporphyrin, which correlates well with the UV spectral data and indicates that chromatographic purification and separation of the extract is efficient. [ABSTRACT FROM AUTHOR]

In the present research work, we intend to examine the crystal growth aspects of the prominent material of Meta-nitroaniline (m-NA) in three different solvents such as methanol, ethanol and acetonitrile such that their comparative structural, as well as physical properties are reported on the basis of the obtained results. All the three single crystals i.e., m-Nitroaniline with methanol as the solvent (NAM), m-Nitroaniline with ethanol as the solvent (NAE), and m-Nitroaniline with acetonitrile as the solvent (NAA) were grown by employing the conventional slow evaporation method. The powder X-ray diffraction (PXRD) study confirms the crystal structure of the grown crystals. The functional groups present in the grown crystals have been verified by FT-IR spectral analysis. The UV–Visible spectrum reveals that all the crystals have comprehensive transparency almost in the entire visible region. NAA crystal has a high band gap value (2.66 eV) compared to the other crystals. The dielectric study reveals a low dielectric constant and low dielectric loss of the crystals at high-frequency ranges and with respect to different temperatures. Thermal stability of the NAM, NAE and NAA crystals are identified to be with the respective melting points of 266, 265, and 268 °C. Hence, the NAA crystal has a high melting point (268 °C) compared to the other crystals. The studies on the electrical and optical properties of these polar solvent crystals reveal that these compounds could be more suited for photonic and NLO applications. [ABSTRACT FROM AUTHOR]

Matrix-based certified reference materials (CRMs) play a central role in the analysis of food contaminants for ensuring measurement accuracy and comparability, as they exhibit the same matrix effects during sample preparation and measurement as the food sample under investigation. However, the availability of such CRMs is still limited. This is also true for matrix CRMs containing polycyclic aromatic hydrocarbons (PAHs), for which maximum levels in food are set in the EU by the Commission Regulation (EU) 2023/915 and in Switzerland by the regulation SR 817.022.15. Therefore, a whey protein powder–based certified reference material (WP-CBR001) was developed according to the requirements of ISO 17034 and the recommendations of ISO Guide 35:2017 containing the four PAHs benz[a]anthracene (BaA), benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), and chrysene (Chr). We show that the choice of solvent is of crucial importance to extract the PAHs completely from this matrix. Only polar and protic solvents such as methanol or water provided access for complete extraction of the PAHs. In contrast, nonpolar and polar aprotic solvents, such as n-hexane or ethyl acetate, exhibited only very low extraction efficiencies below 20%. The certified mass fractions and expanded uncertainties (k = 2) were (3.17 ± 0.32) µg/kg BaA, (4.18 ± 0.48) µg/kg BaP, (4.73 ± 0.49) µg/kg BbF, and (2.85 ± 0.33) µg/kg Chr. These values were verified by an interlaboratory comparison study and by the gravimetric mass fractions obtained from production data. [ABSTRACT FROM AUTHOR]

To study the photoluminescence property of simple silver(I) coordination compounds constructed by 1,3,5-trithian (3S), two new silver(I) polymers, namely, [Ag(3S) (9-AnCO2)]∞ (I, 9-AnCO2 = anthracene carboxylate), and [Ag2(3S)(Ph2PO2)2]∞ (II, Ph2PO2 = diphenylphosphinate), have been prepared and investigated by single-crystal X-ray diffraction (SXRD), fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), solid-state UV–vis absorption spectra (SUV) and photoluminescence spectroscopy (PL). Polymer I represents an electroneutral one-dimensional polymer bridging only by 3S. Polymer II represents an electroneutral one-dimensional polymer co-bridging by 3S and diphenylphosphinate. Both polymers show bright emission at room temperature in the solid-state, cyan light for I, and green light for II. The Aggregation-induced Emission (AIE) phenomenon of II is also observed when gradually adding the weakly polar solvent (ether) to its CH3CN solvent. Our work shows that 3S is an excellent ligand for constructing new luminous coordination compounds. [ABSTRACT FROM AUTHOR]

Concentrated colloidal suspensions of nanorods often exhibit liquid-crystalline (LC) behavior. The transition to a nematic LC phase, with long-range orientational order of the particles, is usually well-captured by Onsager's theory for hard rods, at least qualitatively. The theory shows how the volume fraction at the transition decreases with increasing aspect ratio of the rods. It also explains that the long-range electrostatic repulsive interaction occurring between rods stabilized by their surface charge can significantly increase their effective diameter, resulting in a decrease in the volume fraction at the transition, as compared to sterically stabilized rods. Here, we report on a system of ligand-stabilized LaPO4 nanorods, of aspect ratio ≈ 11, dispersed in apolar medium exhibiting the counter-intuitive observation that the onset of nematic self-assembly occurs at an extremely low volume fraction of ≈ 0.25%, which is lower than observed (≈ 3%) with the same particles when charged-stabilized in polar solvent. Furthermore, the nanorod volume fraction at the transition increases with increasing concentration of ligands, in a similar way as in polar media where increasing the ionic strength leads to surface charge screening. This peculiar system was investigated by dynamic light scattering, Fourier-transform infrared spectroscopy, zetametry, electron microscopy, polarized light microscopy, photoluminescence measurements, and X-ray scattering. Based on these experimental data, we formulate several tentative scenarios that might explain this unexpected phase behavior. However, at this stage, its full understanding remains a pending theoretical challenge. Nevertheless, this study shows that dispersing anisotropic nanoparticles in an apolar solvent may sometimes lead to spontaneous ordering events that defy our intuitive ideas about colloidal systems. [ABSTRACT FROM AUTHOR]

In this study, we investigated graft polymerization of an epoxide monomer, 1,2-butylene oxide (BO), from cellulose in an ionic liquid (1-butyl-3-methylimidazolium chloride (BMIMCl))/N-methyl-2-pyrrolidone (NMP) solvent. The cellulose solution was prepared by immersing a cellulose/BMIMCl solution in NMP. Cellulose in the resulting homogeneous solution was treated with sodium hydride to generate alkoxides, and the mixture was then heated in the presence of BO with stirring under desired conditions for progress of the ring-opening graft polymerization. The 1H NMR and IR spectra of the isolated products suggested occurrence of the graft polymerization to produce polyether (poly(1,2-butylene oxide))-grafted celluloses. The degrees of polymerization of the graft chains were estimated after acetylation of their terminal hydroxy groups to be values up to 5.92, obtained by the reaction at 80 °C for 3 d. The X-ray diffraction results suggested that cellulose chains in the products did not form crystalline structure. The products with the shorter graft chains were soluble in higher polar organic solvents and partly soluble in moderate organic solvents. Solubility for the latter solvents was improved with increasing the graft chain lengths. [ABSTRACT FROM AUTHOR]

Equilibrium mole fraction solubility of salicylic acid in nine aqueous-ethanolic mixtures, as well as in neat water and neat ethanol, was determined at seven temperatures from T = (293.15 to 323.15) K. Salicylic acid solubility in these mixtures was adequately correlated with well-known correlation/prediction methods based on Jouyban-Acree model. Apparent thermodynamic quantities, i.e. Gibbs energy, enthalpy, and entropy, for the dissolution and mixing processes, were computed by means of the van't Hoff and Gibbs equations. The enthalpy–entropy compensation plot of enthalpy vs. Gibbs energy of dissolution was not linear exhibiting positive slopes from neat water to the mixture of w1 = 0.30 and from the mixture of w1 = 0.50 to neat ethanol indicating enthalpy-driven drug transfer processes but negative in the interval of 0.30 < w1 < 0.50 indicating entropy-driven drug transfer processes from more polar to less polar solvent systems. Moreover, by using the inverse Kirkwood–Buff integrals it is observed that salicylic acid is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in those mixtures of 0.24 < x1 < 1.00. [ABSTRACT FROM AUTHOR]

Sets of the nonionic polymers poly(N-vinyl isobutyramide) (pNVIBAm) and poly(N-isopropyl methacrylamide) (pNIPMAm) are synthesized by radical polymerization covering the molar mass range from about 20,000 to 150,000 kg mol−1, and their thermoresponsive and solvent-responsive behaviors in aqueous solution are studied. Both polymers feature a lower critical solution temperature (LCST) apparently of the rare so-called type II, as characteristic for their well-studied analogue poly(N-isopropyl acrylamide) (pNIPAm). Moreover, in analogy to pNIPAm, both polymers exhibit co-nonsolvency behavior in mixtures of water with several co-solvents, including short-chain alcohols as well as a range of polar aprotic solvents. While the cloud points of the aqueous solutions are a few degrees higher than those for pNIPAm and increase in the order pNIPAm < pNVIBAm < pNIPMAm, the co-nonsolvency behavior becomes less pronounced in the order pNIPAm > pNVIBAm > pNIPMAm. Exceptionally, pNIPMAm does not show co-nonsolvency in mixtures of water and N,N-dimethylformamide. [ABSTRACT FROM AUTHOR]

The structure and solvation behavior of binary liquid mixtures of Methanol (MeOH) and N, N-Dimethylformamide (DMF) are explored by ascertaining their intermolecular interactions with either Rhodamine-B (RhB) or Rhodamine101 (Rh101) dye through steady-state absorption, emission, and two-photon induced fluorescence. Specifically, in the present investigation, we examine the strong synergistic solvation observed for the combinations of hydrogen bond donating (MeOH) and accepting (DMF) solvent pairs. Solvatochromism causes the solvatochromic probe molecules to sense increased polarity compared to their bulk counterparts. The origin of synergism was explained in terms of solute–solvent and solvent–solvent interactions in binary solvent mixtures interactions, as evidenced by probe dependence. The solvation behavior of the Methanol and DMF binary solvent mixture shows strong probe dependence, with Rh101 showing synergism while RhB does not. [ABSTRACT FROM AUTHOR]

Lyocell dopes for cellulosic fiber manufacture, i.e., cellulose solutions in N-methylmorpholine-N-oxide monohydrate, are commonly stabilized by propyl gallate, or alternatively by recently proposed gallic acid amide derivatives. In this study, the analysis of the stabilizer and its major degradation products, ellagic acid and ellagoquinone, is investigated. The stabilizer-derived compounds are readily extracted from the dopes with polar aprotic solvents without solvent or cellulose interference. This is followed by the derivatization of the OH groups with a phosphitylation agent and subsequent 31P NMR analysis—an approach frequently used to differentiate and quantify OH groups in lignins. The chemical shifts of the resulting phosphites are reported and structures of the stabilizer derivatives are discussed. The 31P NMR approach offers a straightforward way to analyze the stabilizer chemistry in the Lyocell process. [ABSTRACT FROM AUTHOR]

The aim of the present study is to explore the anti-cancer, anti-oxidant, and anti-obesity potential of saffron petal extract (SPE) prepared through the hydro-alcoholic extraction method. Further partitioning was done with a series of polar and non-polar solvents to find out the most potent fraction of SPE against HCC. Organoleptic characterization depicted the color, odor, taste, and texture of the sub-fractions of SPE. Phytochemical, and pharmacognostic screening of these fractions revealed the presence of alkaloids, flavonoids, carbohydrates, glycosides, and phenols. The quantitative assessment demonstrated that the n-butanol fraction showed maximum phenolic (60.8 mg GAE eq./mg EW), and flavonoid (23.3 mg kaempferol eq./mg EW) content. The anti-oxidant study revealed that the n-butanol fraction exhibited the highest radical scavenging activity, as assessed through DPPH and FRAP assay. The results of the comparative cytotoxic potential also showed n-butanol as the best against liver cancer cells (Huh-7), as it has the least IC50 value (462.8 µg/ml). While other extracts viz., chloroform, n-hexane, ethyl acetate, and aqueous fractions have IC50 values as 1088, 733.9, 1043, and 1245 µg/ml, respectively. Additionally, the n-butanol fraction exerted the highest inhibitory potential against α-amylase (92.5%) and pancreatic lipase enzymes (78%), indicating its anti-adipogenesis property. Based on the current finding, we can deduce that the n-butanol fraction of SPE has better cytotoxic, anti-oxidant, and anti-obesity potential than the other fractions. [ABSTRACT FROM AUTHOR]

An array of disorders caused by excessive alcohol consumption could be attributed to its reactive species (RS) generation power. Studies have reported that polar solvent extract of Ficus exasperata leaves possessed the ability to scavenge radicals, thereby protecting cells against the effects of RS. Ficus exasperata aqueous leaf extract modulations on total thiols, testosterone, and sperm characterisation levels in alcohol-induced reproductive perturbed male rats were studied. Twelve groups (A–L) of rats were used. Group A served as a control (0% alcohol); groups B and C received 40% alcohol (3.2 g·kg−1 body weight) for 4 and 6 weeks, respectively. Groups D, E, and F received only extract-graded doses (125, 250, and 500 mg/kg body weight, respectively) for 2 weeks. After 4 weeks of 40% alcohol administration, groups G, H, and I were treated with the extract-graded doses, while groups J, K, and L were concurrently given the extract-graded doses with alcohol for another 2 weeks. Compared with groups B and C, groups G, H, J, and K serum reduced glutathione increased by 36%, 43%, 82%, and 87%, respectively. In addition, the extracts restored total thiols, testosterone, sperm cell motility, and morphology levels by significantly increasing levels of total thiols, testosterone, and sperm cell motility besides decreasing abnormal sperm cells when compared with groups B and C. Ficus exasperata leaf could be employed in managing reproductive disorders associated with excessive alcohol consumption. [ABSTRACT FROM AUTHOR]

9,9-Bis(4-iodophenyl)xanthene (BIPX) was prepared in good yield by the sequential diazotization–iodination of 9,9-bis(4-aminophenyl)xanthene with a KI/NaNO2/p-TsOH system in acetonitrile at room temperature. A series of novel aromatic polyamides (PAs) were prepared by a carbonylation polymerization of BIPX, aromatic diamines and carbon monoxide in DMAc with Pd(PPh3)2Cl2 as the catalyst in the presence of PPh3 and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU). The resulting PAs bearing inherent viscosity of 0.65–0.75 dL/g were amorphous and readily soluble in organic polar solvents such as NMP, DMF, DMAc, DMSO and Py. These new PAs exhibited good thermal stability with glass-transition temperature of 241–359 °C, 10% weight loss temperature of 480–492 °C and char yield of 47.8–56.7% at 800 °C in nitrogen. Meanwhile, all obtained PAs exhibited low water uptake of 0.98–2.37%, and their transparent, tough and flexible films presented high optical transparency with a cutoff wavelength in the 322–370 nm range and had the tensile strength in the range of 73.4–83.4 MPa, elongation at breakage of 6.7–13.8% and tensile modulus of 1.6–2.2 GPa, respectively. [ABSTRACT FROM AUTHOR]

Inspired by the excellent photochemical properties of hydroxybenzo[h]quinoline and its derivatives, in this work, the novel electron withdrawing nitro substituted HBQ (i.e., NHBQ) fluorophore is explored about its photo-induced behaviors. By investigating the photoexcitation characteristics in different solvents, the solvent-polarity-related photo-induced hydrogen bond of NHBQ indicates polar aprotic solvents largely enhance S1-state hydrogen bond interactions. Charge reorganization stemming from photoexcitation, strengthening excited state hydrogen bond effects, and the polarity-dependent energy gap of frontier molecular orbitals further reveals the excited state intramolecular proton transfer (ESIPT) tendency. Insights into potential energy curves along ESIPT paths in solvents with different polarities, we present that solvent polarity could harness the ESIPT behavior for NHBQ compound. [ABSTRACT FROM AUTHOR]