Extended Hartree-Fock (EHF) theory of chemical reactions

Yamaguchi, Kizashi; Takahara, Yoichi; Fueno, Takayuki; Houk, K. N.

doi:10.1007/bf00527740

Cited by 214 publications

(169 citation statements)

References 46 publications

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“…The quenchings of biradical character by symmetry-allowed orbital interactions are essential in this regard as illustrated by the orbital correlation diagram for the concerted addition of carbonyl ylide to ethylene. These results in turn indicate that the RMP method works well for theoretical locations of the concerted TS as shown previously [20].…”

Section: Concerted Mechanism Of Ozonolysis Reactionssupporting

confidence: 86%

“…On the other hand, the calculated barrier heights for TS1 after the zero point correction are, respectively, 16.3, 5.5 and 2.5 kcal mol by the RMP2 method is in good agreement with the experimental estimation of 5 kcal mol −1 , since the instability of RHF is decreased at TS1. Judging from this result [31] and previous analysis [20], the RMP method was applied to the concerted TSs and APUMP was used for the biradical TS and BR intermediates. Figure 3 illustrates the characteristic of the potential energy hypersurface for the ozonolysis reaction of ethylene revealed by the present APUMP4 4-31G* calculations, where TS1 by Gillies et al [31] was assumed.…”

Section: Concerted Mechanism Of Ozonolysis Reactionsmentioning

confidence: 91%

“…APUMP4 is used as an effective alternative for the CASPT2 approach, since it involves the tetratuple excitations which are essential for correlation corrections in biradical systems [20].…”

Section: Dynamical Correlation Corrections By the Post Hartree-fock Mmentioning

confidence: 99%

“…In fact, the RMP method has been successfully applied to the locations of various concerted TS [20] and concerted TS1 for the addition of O 3 to ethylene [31]. However, a very large stabilization energy (5.8 kcal mol −1 after zero point correction) was predicted by the RMP2 6-31G(d,p) method because of the instability of the zero-order RHF solution for the complex.…”

Section: Concerted Mechanism Of Ozonolysis Reactionsmentioning

confidence: 99%

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Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Yoshioka

Yamaki

Kubo

et al. 1997

Elect J Theoret Chem

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SUMMARYThe different orbitals for different spins molecular orbital and complete active space SCF studies of ozone and carbonyl oxide and related ozonolysis reactions were carried out. The RHF, UHF, approximately spin-projected (AP) UHF and CASSCF calculations were performed to elucidate the covalent bond instability of the oxygenated dipoles. The correlation energies were calculated by RMP4, UMP4, APUMP4 and CASPT2 methods. The locations of concerted transition structures for ozonolysis reactions and the full geometry optimizations of 1,5 biradicals formed by the O-O cleavage of first ozonide were carried out. The implications of these results are discussed in relation to concerted and biradical mechanisms of 1,3-dipolar additions and ozonolyses in gas phases.

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Section: Concerted Mechanism Of Ozonolysis Reactionssupporting

confidence: 86%

Section: Concerted Mechanism Of Ozonolysis Reactionsmentioning

confidence: 91%

“…APUMP4 is used as an effective alternative for the CASPT2 approach, since it involves the tetratuple excitations which are essential for correlation corrections in biradical systems [20].…”

Section: Dynamical Correlation Corrections By the Post Hartree-fock Mmentioning

confidence: 99%

Section: Concerted Mechanism Of Ozonolysis Reactionsmentioning

confidence: 99%

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Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Yoshioka

Yamaki

Kubo

et al. 1997

Elect J Theoret Chem

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“…where we compare the outcomes of the DDCI calculations and those extracted from DFT/B3LYP* calculations relying on the broken symmetry (BS) approach [119,287]. The J SF BS values were extracted using the equation based on the Yamaguchi relation:…”

Section: Universitat Rovira I Virgili From Mononuclear To Dinuclear: mentioning

confidence: 99%

From Mononuclear to Dinuclear: Magnetic Properties of Transition Metal Complexes

Saureu¹

2016

ioChem-BD Computational Chemistry Datasets

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CASSCF, MP2, and CASMP2 studies on addition reaction of singlet molecular oxygen to ethylene molecule

Yoshioka

Tsunesada

Yamaguchi

et al. 1997

Int. J. Quant. Chem.

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ABSTRACT:The reaction mechanism and relative stabilities of the intermediates and transition states in the reaction of 1 O plus ethylene molecule using ab initio molecular 2 Ž . orbital MO theories at several levels of theory with the correction of the nondynamic and dynamic electron correlation effects were systematically investigated. showing that the reaction through the 1,4-biradical intermediates initially proceeds through the gauche transition state to form the gauche minimum 1 BR state, following that the free rotation of O moiety occurs due to the energy barrier less than 4.0 2 kcalrmol. The stability of the perepoxide is surprisingly sensitive to the levels of the Ž . theory and the basis sets employed. The coupled-cluster methods, CCSD and CCSD T , gave the reasonable stabilities of 1,4-biradical intermediates, perepoxide, and dioxetane Ž . as a reaction product. From the results of the CCSD and CCSD T methods, the reaction 1 of O q H C CH proceeds by a two-step mechanism through the 1,4-biradical 2 2 2 intermediates rather than through the perepoxide.

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Extended Hartree-Fock (EHF) theory of chemical reactions

Cited by 214 publications

References 46 publications

Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

From Mononuclear to Dinuclear: Magnetic Properties of Transition Metal Complexes

CASSCF, MP2, and CASMP2 studies on addition reaction of singlet molecular oxygen to ethylene molecule

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