An extension of the anisotropic united atoms intermolecular potential model is proposed for nitriles. The electrostatic part of the intermolecular potential is calculated using atomic charges obtained by a simple Mulliken population analysis. The repulsion-dispersion interaction parameters for methyl and methylene groups are taken from transferable AUA4 literature parameters [Ungerer et al., J. Chem. Phys., 2000, 112, 5499]. Non-bonding Lennard-Jones intermolecular potential parameters are regressed for the carbon and nitrogen atoms of the nitrile group (-C[triple bound] N) from experimental vapor-liquid equilibrium data of acetonitrile. Gibbs Ensemble Monte Carlo simulations and experimental data agreement is very good for acetonitrile, and better than previous molecular potential proposed by Hloucha et al. [J. Chem. Phys., 2000, 113, 5401]. The transferability of the resulting potential is then successfully tested, without any further readjustment, to predict vapor-liquid phase equilibrium of propionitrile and n-butyronitrile.
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http://dx.doi.org/10.1007/s00894-008-0301-4 | DOI Listing |
J Pept Sci
February 2025
Plant Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, UP, India.
Interactions between aromatic side chains of amino acids stabilize the fold and assembly of short peptides. The aromatic π…π and C-H…π interactions have been widely explored in the design of short peptides with specific folding and aggregation patterns. In the present study, we investigated the effect of homologated phenylalanine side chains on the conformation and assembly of peptide helices through X-ray crystallographic structure determination and analysis of five pentapeptides.
View Article and Find Full Text PDFInt J Pharm
December 2024
Guangdong Provincial Key Lab of Green Chemical Product Technology, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:
Investigating the formation mechanism and effective manipulation of multi-component crystal polymorphs is crucial for facilitating industrial drug development. Herein, five novel Osimertinib-caffeic acid forms were first strategically tailored by varying solvent selection. Theoretical analysis demonstrated this polymorphism is correlated with multiple hydrogen bond donors-acceptors within multi-component system, which provides manipulation space for reconfiguration of intermolecular interactions and structural competition, while solvent further induced or involved in hydrogen-bonded rearrangements.
View Article and Find Full Text PDFFood Chem
December 2024
School of Food and Biological Engineering, Key Laboratory of Modern Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei 230601, China. Electronic address:
Plant protein-stabilized Pickering nanoemulsions show potential as plant-based milk substitutes; however, their stability is challenged by mechanical stress during transportation and oxidative deterioration during storage. Herein, soybean isolate protein-curcumin composite nanoparticle (SPI-Cur-NPs)-stabilized Pickering nanoemulsions were converted into microcapsule powders via spray-drying with maltodextrin (MD), trehalose anhydrous (TA), and inulin (IN) as wall materials. Robust intermolecular hydrogen bonds and an amorphous structure were formed using composite wall materials, reducing microcapsule surface fissures while improving encapsulation rate (92.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
School of Chemical Engineering and ARC Centre of Excellence for Enabling Eco-Efficient Beneficiation of Minerals (UQ Node), The University of Queensland, Brisbane, Queensland 4072, Australia. Electronic address:
Hypothesis: Ion-specific forces in concentrated salt solutions play critical roles in many applications, ranging from biology to engineering, e.g., separating water-soluble minerals in brines by flotation using air bubbles.
View Article and Find Full Text PDFSci Rep
December 2024
College of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming, 650500, China.
Drug-drug co-amorphous systems are a promising approach to improve the aqueous solubility of poorly water-soluble drugs. This study explores the combination of breviscapine (BRE) and matrine (MAT) form an amorphous salt, aiming to synergistically enhance the solubility and dissolution of BRE. In silico analysis of electrostatic potential and local ionization energy were conducted on BRE-MAT complex to predict the intermolecular interactions, and solvent-free energies were calculated using thermodynamic integration and density functional theory.
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