We describe automated procedures for the first stages of a systematic computational investigation of reaction mechanisms. They include (i) selection of computational method and basis set based on statistical analysis of structural and energy data relating to experimental values, (ii) determination of all distinct conformations of transition states with large conformational freedom, and (iii) generation of unknown geometry of the transition states, based on pre-defined connectivity of the atoms involved in the reaction. For the conformational search we employed an efficient procedure for exploration of various possible conformations of the transition states and elimination of the equivalent structures in several steps using molecular-mechanical and quantum-mechanical methods. The procedure was applied to the determination of the structures of transition states and intermediates in the ammonolysis of monoformylated 1,2-ethanediol, which were subsequently used for identification of the lowest energy reaction paths. For the same reaction system we also used the approach for generation of the initial structures of transition states with unknown geometry. The reported procedures are implemented in the MolRan program suite.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jmgm.2010.07.006 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Observation of Large Low-Field Magnetoresistance in Layered (NdNiO):NdO Films at High Temperatures.
Adv Mater
January 2025
State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
Large low-field magnetoresistance (LFMR, < 1 T), related to the spin-disorder scattering or spin-polarized tunneling at boundaries of polycrystalline manganates, holds considerable promise for the development of low-power and ultrafast magnetic devices. However, achieving significant LFMR typically necessitates extremely low temperatures due to diminishing spin polarization as temperature rises. To address this challenge, one strategy involves incorporating Ruddlesden-Popper structures (ABO):AO, which are layered derivatives of perovskite structure capable of potentially inducing heightened magnetic fluctuations at higher temperatures.
View Article and Find Full Text PDFBeyond Inducing Anionic Redox: Controllable Migration Sequence of Li Ions in Transition Metal Layers Toward Highly Stable Li-Rich Cathodes.
Adv Mater
January 2025
Center of Energy Storage Materials and Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid-State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
The energy density of layered oxides of Li-ion batteries can be enhanced by inducing oxygen redox through replacing transition metal (TM) ions with Li ions in the TM layer. Undesirably, the cathodes always suffer from unfavorable structural degradation, which is closely associated with irreversible TM migration and slab gliding, resulting in continuous capacity and voltage decay. Herein, attention is paid to the Li ions in the TM layer (Li) and find their extra effects beyond inducing oxygen redox, which has been rarely mentioned.
View Article and Find Full Text PDFEffective One-for-All Phototheranostic Agent for Hypoxia-Tolerant NIR-II Fluorescent/PA Image-Guided Phototherapy.
Small
January 2025
Biomaterials Research Center, School of Biomedical Engineering, Southern Medical University, Guangzhou, 510515, P. R. China.
Near-infrared (NIR)-triggered type-I photosensitizers are crucial to address the constraints of hypoxic tumor microenvironments in phototherapy; however, significant challenges remain. By selecting an electron-deficient unit, a matched energy gap in the upper-level state is instrumental in boosting the efficiency of intersystem crossing for the type-I electron transfer process. 2-Cyanothiazole, an electron acceptor, is covalently linked with N, N-diphenyl-4-(thiophen-2-yl)aniline to yield a multifunctional photosensitizer (TTNH) that exhibits intrinsic NIR absorbance and compatible T energy levels, facilitating both radiative and nonradiative transitions.
View Article and Find Full Text PDFConcise Synthesis of (-)-Veratramine and (-)-20--Veratramine via Aromative Diels-Alder Reaction.
J Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
A concise and convergent synthesis of the isosteroidal alkaloids veratramine and 20--veratramine has been accomplished. A Horner-Wadsworth-Emmons olefination joins two chiral building blocks of approximately equal complexity and a transition-metal catalyzed intramolecular Diels-Alder cycloaddition-aromatization cascade constructs the tetrasubstituted arene. Other key steps include a highly diastereoselective crotylation of an -sulfonyl iminium ion and an Eschenmoser fragmentation.
View Article and Find Full Text PDFSolar Evaporator with Dual Gradient Heating Effect for Sustained and Efficient Desalination.
Small
January 2025
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China.
Solar desalination shows promise in tackling freshwater shortages, but challenges arise from the trade-off between water transportation and heat supply, affecting evaporators' efficiency and salt resistance. Additionally, intermittent nature of solar radiation significantly diminishes overall evaporative performance. This study presents dual-gradient heating solar evaporator for efficient desalination.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!