Article
Chemistry, Physical
Michael J. Frisch, George A. Petersson, Jason M. Breslin
Summary: Bond lengths have been calculated for a test set of diatomic species using the PFD-3B functional, which shows significantly better performance than other DFT methods. The calculated values are in good agreement with experimental data, indicating the reliability of this method.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Michele Cutini, Piero Ugliengo
Summary: In this study, the vibrational spectral features of collagen triple helix were investigated using DFT-D approach, with the protein simulated in different environments. The study showed that IR spectroscopy can detect small variations in collagen helicity and provide insight into the packing state of collagen. So far, identifying collagen helicity has only been possible through crystal x-ray diffraction.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Adam A. Kelemen, Andras Perczel, Daniel Horvath, Imre Jakli
Summary: The cis-trans isomerization of amide bonds plays a crucial role in the structural and functional changes of proteins. This study investigates the energetics of cis-trans isomerization in N-methylacetamide center dot 2H(2)O at different protonation states. The results reveal that the barriers for cis-trans interconversion at room temperature are too high, but a previously undescribed low energy transition state suggests a pathway for the proton transfer, enabling the trans -> cis transition to occur.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Maria del Rosario Merino-Garcia, Luis Antonio Soriano-Agueda, Juan de Dios Guzman-Hernandez, Diego Martinez-Otero, Bruno Landeros Rivera, Fernando Cortes-Guzman, Jose Enrique Barquera-Lozada, Vojtech Jancik
Summary: This study experimentally investigates the charge density distribution of borazine crystals and reveals that borazine has a weakly aromatic character, unlike benzene. The analysis of intermolecular interactions further supports the weakly aromatic nature of borazine.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Taylor Harville, Mark S. Gordon
Summary: This article introduces the application of quasi-atomic orbital (QUAO) bonding analysis to study intramolecular hydrogen bonding (IMHB) in salicylic acid and an intermediate involved in the synthesis of aspirin. By directly accessing information intrinsic to the molecular wave function, this method rigorously explores IMHB and avoids the need for biased methods. Variables affecting the strength of IMHB are determined through kinetic bond orders, QUAO populations, and QUAO hybridizations. Important properties include the interatomic distance between hydrogen and oxygen involved in the IMHB and the oxygen's hybridization. Furthermore, the analysis reveals that each intramolecular hydrogen bond is a four-electron three-center bond. Additionally, the bonding analysis provides insights into how aromatic reactivity changes due to the influence of functional groups on the aromatic ring.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Sang Loon Tan, Laura N. F. Cardoso, Marcus V. N. de Souza, Solange M. S. Wardell, James L. Wardell, Edward R. T. Tiekink
Summary: The crystal of (2-thienyl)CH2CON(H)-N.C(H)Ph was found to exhibit parallel, offset pi[C(= O)N(H)N = C]...pi(phenyl) interactions alongside more conventional non-covalent interactions. Analysis of the interactions showed that the pi[C(= O)N(H)N = C]...pi(phenyl) interactions are attractive, providing an energy of association of about 15 kJ mol(-1) in the molecular packing. These interactions occur in approximately 5-6% of crystals where they can potentially occur, according to a survey of related structures in the literature.
Article
Engineering, Electrical & Electronic
Alican Uysal, Funda Akleman
Summary: This paper presents a novel method based on generalized scattering matrix representation to analyze radiowave propagation. The method uses Hermite-Gaussian basis functions to obtain the scattering relations of cascaded two port networks. By using simple matrix operations, the method calculates the field variation at the boundaries of the problem domain. The proposed method shows accurate results in numerical examples and can be extended to more complex and large domain electromagnetic problems with its systematic methodology.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Timothy D. Lash, Deyaa AbuSalim, Gregory M. Ferrence
Summary: The successful synthesis of telluracarbaporphyrins and oxacarbatripyrrin derivatives was achieved, and it was found that the tellurium-nitrogen interactions could affect the molecular conformation and stability. Structural characterization and crystallographic analysis revealed the structures and properties of these novel molecules.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Hengyuan Shen, Srimukh Prasad Veccham, Martin Head-Gordon
Summary: Energy decomposition analysis is a useful method to understand the different components of intermolecular interaction energy. This article presents a nonperturbative polarization analysis to accurately decompose polarization energy into fragment-wise contributions using complementary occupied-virtual pair analysis. The results demonstrate that the polarization process is different from the charge transfer process, providing another reason for separating these two processes in energy decomposition analysis.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Lu Rao, Fan Wang
Summary: In this work, the authors employ the DMC method to calculate the energies of singlet and triplet states for a series of organic diradicals and diatomic diradicals. They investigate the influence of different trial wavefunctions and orbitals on the DMC energies. The results show that MDJ with ROB3LYP orbitals yields the lowest energies for organic diradicals, while the choice of orbitals does not significantly affect the energies of diatomic diradicals. Furthermore, MDJ can reduce the DMC energies for most of the investigated diradicals. The singlet-triplet gaps can be reasonably calculated using MDJ with a mean absolute error of less than 2 kcal/mol.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Mathematics
Chih-Yu Liu, Cheng-Yu Ku
Summary: This article proposes a simplified radial basis function method using exterior fictitious sources to solve elliptic boundary value problems, improving accuracy without the need to find the optimum shape parameter.
Article
Biochemistry & Molecular Biology
Mikhail Yu. Lobanov, Leonid B. Pereyaslavets, Ilya V. Likhachev, Bakhyt T. Matkarimov, Oxana V. Galzitskaya
Summary: This study evaluated the favorability of different conformations of aromatic residues in proteins by analyzing their occurrences, concluding that an angle of 60 degrees between interacting aromatic residues is the most favorable arrangement. The research also found that pairs with a parallel arrangement of aromatic residues were twice as much as expected, and the His-His pair occurred twice as frequently as expected. A server called CARP has been created for calculating essential structural features of aromatic residues in proteins.
COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL
(2021)
Article
Chemistry, Physical
Vera M. Shakhova, Daniil A. Maltsev, Yuriy Lomachuk, Nikolai S. Mosyagin, Leonid Skripnikov, Anatoly Titov
Summary: The compound-tunable embedding potential (CTEP) method is applied to study the electronic structure and interatomic distances in crystals containing lanthanide atoms. The results show that CTEP is capable of accurately describing the properties of Yb-containing crystals.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Harish S. Kunchur, Sachin C. Sonawane, Prateek Saini, Srinivasan Ramakrishnan, Maravanji S. Balakrishna
Summary: This study investigates the reactions of amide functionalized bisphosphine with copper salts, leading to the formation of chelate complexes with weak N-HCu interactions. Additionally, halide-free dimeric Cu-I complexes show excellent metal-ligand cooperativity in the catalytic oxidative dehydrogenative carboxylation of unactivated cycloalkanes to form allylic esters through C-H bond activation.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Markus Rauhalahti, Dage Sundholm, Mikael P. Johansson
Summary: The magnetically induced current density of a novel naphthalene-fused heteroporphyrin has been studied using a quantum-chemical method, revealing high aromatic properties and a branching of the global ring current at three specific points, forming eight pathways.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Organic
Fuying Zhu, Yamei Lin
Summary: In this study, a low-metal iron-supported catalyst (Fe20/NC-Mg) was reported for the efficient synthesis of quinoxaline compounds, using water as a solvent and without additional bases. The synergistic effect of FeNx site and Mg (OH)2 nanorods in the catalyst played a key role in achieving high yields (82-91%) in 16 examples. The gram-level synthesis and reusability of the catalysts after four cycles demonstrated its industrial application potential.
Article
Chemistry, Organic
Mikhail Kozlov, Alexey Tyurin, Andrey Dmitrenok, Vyacheslav Rusak, Aleksander Fedorov, Igor Zavarzin, Yulia Volkova
Summary: This study presents a novel and practical synthesis method for phosphorus-substituted 1,3,4-thiadiazolines using phosphorylthioformic acid hydrazides and ketones. The protocol demonstrates operational simplicity, availability of reagents, and tolerance towards different functional groups.
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.
