Insights into the reaction mechanism between phosphacyclopropenylidene and methyleneimine: A theoretical study

2020 ◽  
Vol 19 (3) ◽  
pp. 237-244
Author(s):  
Yilin Wang ◽  
Mengyao Wu ◽  
Xiaojun Tan ◽  
Jinsong Gu
Keyword(s):  
Reaction Mechanism ◽  
Energy Surface ◽  
Theoretical Study ◽  
Stationary Points ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Tricyclic Compound ◽  
Alternative Approach ◽  
Electron Withdrawing Group

The reaction mechanism between phosphacyclopropenylidene and methyleneimine has been systematically investigated at the M06–2X/6–311++G(d,p) level of theory in order to better understand the reactivity of unsaturated cyclic phosphorus-bearing carbene. Geometry optimizations and vibrational analyses have been conducted for the stationary points on the potential energy surface of the system. Calculations show that the spiro bicyclic intermediate could be produced through the cycloaddition process between phosphacyclopropenylidene and methyleneimine initially. The reaction mechanism is illustrated with frontier molecular orbital theory. Introduction of electron-withdrawing group in phosphacyclopropenylidene will better facilitate the addition process. Through subsequent ring-expanding and hydrogen-migrating process, fuse-ring and allene compounds could be produced, respectively. Furthermore, it’s easy for spiro bicyclic intermediate and another methyleneimine to form a spiro tricyclic compound. This study is helpful to understand the reactivity of phosphacyclopropenylidene, the evolution of phosphorus-bearing molecules in space, and to offer an alternative approach to the formation of phosphorus-bearing heterocyclic compound.

scholarly journals Theoretical study on the reaction between phosphacyclopropenylidene and ethylene: An alternative approach to the formation of phosphorus-bearing heterocyclic compound

2020 ◽  
Vol 85 (9) ◽  
pp. 1175-1184
Author(s):  
Mengyao Wu ◽  
Yilin Wang ◽  
Xiaojun Tan ◽  
Jinsong Gu
Keyword(s):  
Reaction Mechanism ◽  
Heterocyclic Compound ◽  
Energy Surface ◽  
Theoretical Study ◽  
Stationary Points ◽  
Frontier Molecular Orbital ◽  
Orbital Theory ◽  
Tricyclic Compound ◽  
Alternative Approach ◽  
Electron Withdrawing Group

The reaction mechanism between phosphacyclopropenylidene and ethylene has been systematically investigated at the B3LYP/6-311++G(d,p) level of theory in order to better understand the reactivity of unsaturated cyclic phosphorus-bearing carbene. Geometry optimizations and vibrational analyses have been performed for the stationary points on the potential energy surface of the system. Calculations show that the spiro bicyclic intermediate could be produced through the cycloaddition process between phosphacyclopropenylidene and ethylene initially. The reaction mechanism is illustrated with the frontier molecular orbital theory. Introduction of electron-withdrawing group in phosphacyclopropenylidene will better facilitate the addition process. Through subsequent ring-expanding and hydrogen-migrating process, fuse-ring and allene compounds could be produced, respectively. Furthermore, it?s easy for spiro bicyclic intermediate and another ethylene to form a spiro tricyclic compound. This study is helps to understand the reactivity of phosphacyclopropenylidene, the evolution of phosphorus-bearing molecules in space, and to offer an alternative approach to the formation of phosphorus-bearing heterocyclic compound.

scholarly journals Theoretical study on the reaction between silacyclopropenylidene and three-membered heterocyclic compounds (azirane and oxirane): An alternative approach to the formation of heterocyclic silylene

2020 ◽  
Vol 45 ◽  
pp. 146867832090205
Author(s):  
Xiaojun Tan ◽  
Mengyao Wu ◽  
Yilin Wang ◽  
Guizhi Shi ◽  
Jinsong Gu
Keyword(s):  
Reaction Mechanism ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Heterocyclic Compounds ◽  
Energy Surface ◽  
Theoretical Study ◽  
Stationary Points ◽  
Dissociation Process ◽  
Alternative Approach ◽  
Insertion Process

The reaction mechanism between silacyclopropenylidene and three-membered heterocyclic compounds (azirane and oxirane) has been systematically investigated at the B3LYP/6-311+G* level of theory in order to better understand the reactivity of unsaturated cyclic silylene. Geometry optimizations and vibrational analyses have been conducted for the stationary points on the potential energy surface of the system. Calculations show that the Si-spiroheterocyclic intermediate and four-membered heterocyclic silylene compound could be produced through the insertion process and subsequent dissociation process between silacyclopropenylidene and three-membered heterocyclic compounds. For the insertion process, it is easier for silacyclopropenylidene to insert into C-N bond of azirane than into C-O bond of oxirane. This study is helpful to understand the reactivity of silacyclopropenylidene, the evolution of silicon-bearing molecules in space, and to offer an alternative approach to the formation of enlarged heterocyclic silylene compound.

scholarly journals Ab initio study regarding the evaluation of the antioxidant character of cyanidin, delphinidin and malvidin

2012 ◽  
Vol 10 (1) ◽  
pp. 180-186 ◽  
Author(s):  
Raluca Pop ◽  
Mariana Ştefănut ◽  
Adina Căta ◽  
Cristian Tănasie ◽  
Mihai Medeleanu
Keyword(s):  
Ab Initio ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Frontier Molecular Orbital ◽  
Hydroxyl Groups ◽  
Molecular Orbital Theory ◽  
Ab Initio Study ◽  
Wide Spread ◽  
Orbital Theory ◽  
Dissociation Enthalpy

AbstractA theoretical study regarding the evaluation of the antioxidant character of three of the most wide-spread anthocyanidins (cyanidin, delphinidin and malvidin) was carried out at ab initio level. Different parameters (bond dissociation enthalpy, ionization potential, proton affinity, and electron transfer enthalpy) were computed for each OH group of the compounds in order to predict their antioxidant capacity. Several molecular descriptors based on frontier molecular orbital theory (hardness, electrophilicity, frontier charge density) were also calculated, as well as the atomic charges corresponding to the O atoms of the hydroxyl groups.

THEORETICAL STUDY ON THE SELF-REACTION MECHANISM OF CH2ClO2 RADICALS

2009 ◽  
Vol 08 (01) ◽  
pp. 119-142 ◽  
Author(s):  
WEN-MEI WEI ◽  
REN-HUI ZHENG ◽  
YAN TIAN ◽  
ZHI-HONG GU ◽  
YONG-YAN XIE
Keyword(s):  
Reaction Mechanism ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Complex Potential ◽  
Energy Surface ◽  
Theoretical Study ◽  
Transition States ◽  
The Self ◽  
Stationary Points ◽  
Energy Barriers

The complex potential energy surface for the self-reaction of CH 2 ClO 2 radicals, including 12 intermediates, 33 interconversion transition states, and 21 major dissociation products, was theoretically probed at the CCSD(T)/cc-pVDZ//B3LYP/6-311G(2d,2p) level of theory. The geometries and relative energies for various stationary points were determined. Based on the calculated CCSD(T)/cc-pVDZ potential energy surface, the possible mechanism for the studied system was proposed. It is shown that the most feasible channels are those leading to 22 CH 2 ClO + 3 O 2, 2 CH 2 ClO + 2 HO 2 + CHClO , 2 CH 2 ClO + HCl + 2 CH(O)O 2, 2 CH 2 ClO + 3 O 2 + 2 Cl + CH 2 O , and p,s,o- CH 2 ClOOOCl + CH 2 O with the energy barriers of 5.6, 11.8, 12.4, 12.4, and 13.5 kcal/mol, respectively. Their mechanisms are that CH 2 ClO 2 and CH 2 ClO 2 form a tetroxide intermediate first, then the intermediate dissociates to yield the productions or through multi-steps reactions to produce the final products.

A FIRST PRINCIPLE ANALYSIS ON THE STRUCTURAL AND PHOTO-INDUCED CHARGE TRANSFER IN RUTHENIUM COMPLEXES OF HEXAAZATRIPHENYLENE

2012 ◽  
Vol 11 (04) ◽  
pp. 895-905 ◽  
Author(s):  
SHA-SHA LIU ◽  
XIAO-XIA LIU ◽  
KANG QIU ◽  
PENG SONG
Keyword(s):  
Charge Transfer ◽  
Quantum Chemical ◽  
Absorption Maximum ◽  
Frontier Molecular Orbital ◽  
First Principle ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Difference Density ◽  
Charge Difference Density ◽  
Induced Charge

Three complexes [ Ru ( CN )4( HAT )]2-( HAT = hexaazatriphenylene ;[ Ru 1]2-), [{ Ru ( CN )4}2 (μ2- HAT )]4-([ Ru 2]4-) and [{ Ru ( CN )4}3(μ3- HAT )]6-([ Ru 3]6-) for supramolecular assemblies are investigated by quantum-chemical calculations. Due to symmetry of complexes, the energy level differences are 2.014 eV and 2.019 eV for [ Ru 2]4- and [ Ru 3]6- complex, which are about 0.4 eV larger than that for [ Ru 1]2- complex. The absorption maximum for [ Ru 1]2- complex in water is at 375.8 nm. Coordination of the second and third Ru(II) center to produce [ Ru 2]4- and [ Ru 3]6- result in a red-shift of this strongest absorption to 453.4 nm and 468.1 nm, respectively. Absorption maximum of three complexes belong to MLCT transitions, which are revealed by frontier molecular orbital theory and charge difference density method.

Bicyclo[2.1.1]hex-1-yl Cation: an Ab Initio Study of the C6H9+ Potential-Energy Surface

1993 ◽  
Vol 46 (8) ◽  
pp. 1301 ◽  
Author(s):  
CH Schiesser
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Gas Phase ◽  
Energy Barrier ◽  
Energy Surface ◽  
Molecular Orbital Theory ◽  
Extensive Investigation ◽  
Ab Initio Study ◽  
Orbital Theory

An extensive investigation of the C6H9+ potential-energy surface by ab initio molecular orbital theory is reported. Calculations at the RHF/6-31G* level of theory predict that the bicyclo[2.1.1]hex-1-yl cation (2b) rearranges to the 3-methylenecyclopentyl cation (7b) with an energy barrier of only 0.3 kJ mol-1. Inclusion of electron correlation in the calculation casts doubt on the gas-phase existence of (2b) which is predicted to rearrange without barrier at the MP2/6-31G* level of theory.

A Theoretical Study of the Stevens Rearrangement of Methylammonium Methylide and Methylammonium Formylmethylide

1993 ◽  
Vol 46 (9) ◽  
pp. 1375 ◽  
Author(s):  
GL Heard ◽  
KE Frankcombe ◽  
BF Yates
Keyword(s):  
Free Radical ◽  
Theoretical Study ◽  
Energy Difference ◽  
Reaction Pathways ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Radical Process ◽  
Stevens Rearrangement ◽  
Semi Empirical ◽  
Free Radical Process

Ab initio and semi-empirical molecular orbital theory has been used to study the reaction pathways of the Stevens rearrangement of the prototype methylammonium methylide and methylammonium formylmethylide . For both reactions, the stepwise (free radical) process is predicted to require less energy than the concerted rearrangement (in accordance with experimental suggestions). With inclusion of electron correlation, the energy difference between these pathways is reduced; however, for the smaller system at the CCSD/6-31G(d) level of theory, the free radical process is still favoured by over 180 kJ mol-1. For both systems, the concerted transition structures for the pericyclic mechanisms reveal that some amount of bonding is retained in these formally symmetry-forbidden processes.

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