Acetonitrile, a polar molecule that cannot form hydrogen bonds on its own, interacts with solvent molecules mainly through the lone pair of its nitrogen atom and the π electrons of its CN triple bond [Correction added on 17 July 2024, after first online publication: Acetole has been changed to Acetonitrile in the preceeding sentence.]. Interestingly, acetonitrile exhibits an unexpected strengthening of the triple bond\'s force constant in an aqueous environment, leading to an upshift (blueshift) in the corresponding stretching vibration: this effect contrasts with the usual consequence of hydrogen bonding on the vibrational frequencies of the acceptor groups, that is, frequency redshift. This investigation elucidates this phenomenon using Raman spectroscopy to examine the behavior of acetonitrile in organic solvent, water, and silver ion aqueous solutions, where an even more pronounced upshift is observed. Raman spectroscopy is particularly well suited for analyzing aqueous solutions due to the minimal scattering effect of water molecules across most of the vibrational spectrum. Computational approaches, both static and dynamical, based on Density Functional Theory and hybrid functionals, are employed here to interpret these findings, and accurately reproduce the vibrational frequencies of acetonitrile in different environments. Our calculations also allow an explanation for this unique behavior in terms of electric charge displacements. On the other hand, the study of the interaction of acetonitrile with water molecules and metal ions is relevant for the use of this molecule as a solvent in both chemical and pharmaceutical applications.

Raman spectroscopy allows for the unambiguous identification of materials through the inelastic scattering of light. This technique has a great many uses in various aspects of society from academic, scientific, and industry. This paper explores a specific type of Raman spectrometer called a spatial heterodyne Raman spectrometer (SHRSy), which is a variation of an interferometric spectrometer. It utilizes a Michelson interferometer and replaces the mirrors with gratings that transform it from a time-domain spectrometer to a spatial-domain spectrometer, allowing for the entirety of the spectrum to be captured at once. This study specifically tests a half-inch two-grating monolithic SHRS (½-in. 2g-mSHRS), which has a weight of <60 g and a size of 2.2 × 2.2 × 1.3 cm. To do this we excite a variety of organic liquids with a 532 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) pulsed laser, using an excitation energy of 6.5 mJ/pulse and distance of 3 m in conjunction with an intensified charge-coupled device camera. This is the first time that the SHRS has been used for investigating polarized Raman spectra of liquids. We discuss and contrast the instrumental properties such as resolution, spectral range, étendue, and field of view with previously tested mSHRS to give context to the instrument\'s performance.

Following previous studies, the ternary mixture of methanol/formamide/acetonitrile (MeOH/Formamide/MeCN) was studied using the UV-Vis absorption spectra at 298.15 K with a set of five probes, 4-nitroaniline, 4-nitroanisole, 4-nitrophenol, N,N-dimethyl-4-nitroaniline and 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenolate (Reichardt betaine dye), for a total of 22 mole ternary fractions. In addition, nine mole fractions of the underling binary mixtures, MeOH/Formamide and Formamide/MeCN were also tested. Spectroscopic results were used to model the preferential solvation order for each probe in the mixtures. The Kamlet-Taft solvatochromic solvent parameters, α, β, and π*, were also computed through the use of the solvatochromic shifts of the five probe indicators. Moreover, discrepancies in the spectroscopic behavior of 4-nitrophenol in formamide-rich mixtures were observed and analyzed.

Volatile organic compounds (VOCs) are in the vapor state in the atmosphere and are considered pollutants. Density functional theory (DFT) calculations with the wb97xd exchange correlation functional and the 6-311+G(d,p) basis set are carried out to explore the potential possibility of palladium-doped single-walled carbon nanotubes (Pd/SWCNT-V), serving as the resource for detecting and/or adsorbing acetonitrile (ACN), styrene (STY), and perchloroethylene (PCE) molecules as VOCs. The suggested adsorbent in this study is discussed with structural parameters, frontier molecular orbital theory, molecular electrical potential surfaces (MEPSs), natural bond orbital (NBO) analyses, and the density of states. Furthermore, following the Bader theory of atoms in molecules (AIM), the topological properties of the electron density contributions for intermolecular interactions are analyzed. The obtained results show efficient VOC loading via a strong chemisorption process with a mean adsorption energy of -0.94, -1.27, and -0.54 eV for ACN, STY, and PCE, respectively. Our results show that the Pd/SWCNT-V can be considered a good candidate for VOC removal from the environment.

Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and a star medication used to treat non-small-cell lung carcinomas (NSCLCs). It has caused broad public concern that osimertinib has relatively low stability in plasma. We explored why osimertinib and its primary metabolites AZ-5104 and AZ-7550 are unstable in rat plasma. Our results suggested that it is the main reason inducing their unstable phenomenon that the Michael addition reaction was putatively produced between the Michael acceptor of osimertinib and the cysteine in the plasma matrix. Consequently, we identified a method to stabilize osimertinib and its metabolite contents in plasma. The assay was observed to enhance the stability of osimertinib, AZ-5104, and AZ-7550 significantly. The validated method was subsequently applied to perform the pharmacokinetic study for osimertinib in rats with the newly established, elegant, and optimized ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) strategy. The assay was assessed for accuracy, precision, matrix effects, recovery, and stability. This study can help understand the pharmacological effects of osimertinib and promote a solution for the similar problem of other Michael acceptor-contained third-generation EGFR-TKI.

The present study reports the spectroscopic characterization and second hyperpolarizability of odd spin states of acetonitrile in gas phase and water solvent. The odd spin states of acetonitrile are singlet, triplet and quintet spin state of acetonitrile have been considered for the study. The spectroscopic characterization viz. energy, geometrical parameters, infrared and electronic absorption spectra, molecular orbitals (MOs) their energies and natural transitions orbitals (NTOs) in gas phase and water solvent state reported at B3LYP/aug-cc-pVDZ level of theory. The second hyperpolarizability values are obtained using various methods and basis sets for comparison. It has been observed that the second hyperpolarizability values for the odd spin states of acetonitrile are more positive than the first hyperpolarizability. It is clearly seen that the effect of spin on spectroscopic parameters except on energy. The singlet gas phase acetonitrile calculations are well matching with the available experimental determinations. The TDDFT approach has been used to study electronic absorption spectra of all spin states of acetonitrile in gas phase and in water solvent. The IEFPCM model implemented in studying acetonitrile in water solvent at B3LYP/aug-cc-pVDZ level of theory. It is observed that HOMO to LUMO gap is larger for singlet than the triplet and quintet spin state and it decrease with an increase in strength of an applied field. All these calculations performed using Gaussian 16 program package.

Detergent-soluble proteins (DSPs) are commonly dissolved in lipid buffers for NMR experiments, but the huge lipid proton signal prevents recording of high-quality spectra. The use of costly deuterated lipids is thus required to replace nondeuterated ones. With conventional methods, detergents like dodecylphosphocholine (DPC) cannot be fully exchanged due to their high binding affinity to hydrophobic proteins. We propose an original and simple protocol which combines the use of acetonitrile, dialysis and lyophilization to disrupt the binding of lipids to the protein and allow their indirect replacement by their deuterated equivalents, while maintaining the native structure of the protein. Moreover, by this protocol, the detergent-to-protein molar ratio can be controlled as it challenges the protein structure. This protocol was applied to solubilize the Vpx protein that was followed upon addition of DPC-d38 by 1 H-15 N SOFAST-HMQC spectra and the best detergent-to-DSPs molar ratio was obtained for structural studies.

The development of methods for the efficient and reliable separation and routine analysis of rare-earth elements (REEs), including samarium (Sm), proceeds to draw in the interest of the many researchers, attributable to the similar physical and chemical properties of these elements. Note that although the voltammetric determination of Sm has been described in the literature, thus far, no chemometric and voltammetric methods for the quantification of the element in its mixtures with other lanthanides in an acetonitrile solution have been reported. This work was aimed toward the advancement of a method for the detection of Sm in acetonitrile, the intended function of which was to obtain a selective current response of Sm by Differential Pulse Voltammetry, utilizing the Box-Behnken experimental design, to identify the best conditions for the determination. In particular, the three selected factors for the experiment, namely the potential range, amplitude modulation, and the deposition time, were found to have optimal conditions of -1.5 to +1.0 V, 0.075 V, and 60 s, consecutively. The optimal conditions were observed to result in a selective current response for samarium with a detection limit of 2.25 mg/L and a limit of quantitation of 7.50 mg/L. Furthermore, the accuracy was 98.70% and the precision was found to be 1.91% in relative standard deviation (RSD), while the recovery was found to be 98.70%.

We report the low-temperature studies of liquid CH3CN by Raman spectral measurements at ambient pressure with decreasing the temperature from 20 to -196 °C. Detailed internal modes especially the lattice modes analysis revealed that the structural phase transitions of acetonitrile from liquid to solid phase β and solid phase β to solid phase α were occurring at -50 and -60 °C, respectively. Further, the Fermi resonance parameters between the fundamental ν2 and combination (ν3 + ν4) of CH3CN at different temperatures were calculated based on the Bertran\'s equations. It is found that the Fermi resonance parameters as a function of temperature become discontinued at -50 and -60 °C, which coincides with discontinuities observed in the Raman shifts of CH3CN at -50 and -60 °C. The results suggest that the Fermi resonance parameters could be used as an indicator to assess the structural phase transition for CH3CN under low temperature.

The mixtures of ionic liquid (IL) and acetonitrile (CH3CN) can be used as reaction media, supercapacitors and thermally stable electrolytes. The macroscopic properties of ILs-CH3CN mixtures have been extensively studied. However, some fundamental questions regarding the microscopic properties of ILs-CH3CN mixtures still remain to be answered. In this work, the structure properties and hydrogen-bond interactions of two task-specific ILs, i.e., 1-propylnitrile-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([PCNMIM][Tf2N]) and 1-(2\'-hydroxylethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2OHMIM][Tf2N]), and CH3CN were studied using the combination of Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) calculations. The aromatic C‒H stretching vibration region of the cation was an area of special focus. Excess infrared spectroscopy with enhanced resolution was applied to analyse the original infrared spectra. It is found that: (1) The two ILs form stable hydrogen-bonds with CH3CN. (2) Ion cluster, ion cluster-acetonitrile, and ion pair-acetonitrile are identified in the mixture. Acetonitrile cannot break apart the strong electronic interaction between the cation and anion in the examined concentration range. (3) The hydrogen-bonds are weak strength, closed shell and electrostatic dominant interactions. (4) The preferred interaction site of [PCNMIM]+ cation is the hydrogen atom at the C2 site, while that of [C2OHMIM]+ cation is the hydrogen atom in the hydroxyl group.