Systematic comparison of the benzynes, pyridynes, and pyridynium cations and characterization of the Bergman cyclization of Z-but-1-en-3-yn-1-yl isonitrile to the meta diradical 2,4-pyridyne

Debbert, Stefan L.; Cramer, Christopher J.

doi:10.1016/s1387-3806(00)00160-3

Cited by 73 publications

(108 citation statements)

References 74 publications

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“…The intermediate bicyclic benzazirine 3 must be regarded as somewhat remarkable, insofar as two of its bonds certainly must be among the weakest CC and CN bonds ever characterized—the bond strengths range from 0.4 to 8.7 kcal⋅mol −1 depending on the level of theory. The very weak CC bond, to the extent it may be regarded as a 1,3‐interaction in a didehydroazepine, is reminiscent of the situation found in m ‐benzynes 80–85 and corresponding pyridynes 84, 86. As is found in these aryne systems, the shallow nature of the bond stretching coordinate gives rise to very large differences between the CAS and DFT levels of theory with respect to the CC bond length in 3 ( r 2 in Table II).…”

Section: Discussionmentioning

confidence: 85%

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

Johnson

Sullivan

Cramer³

2001

Int J of Quantum Chemistry

151

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ABSTRACT:The electronic structures of the triplet ground states and first three excited singlet states for phenylnitrene, 14 meta-, and 17 para-substituted congeners have been characterized using density functional theory and multireference second-order perturbation theory (CASPT2). Ring expansion pathways to form didehydroazepines have activation enthalpies of about 9 kcal · mol −1 and are fairly insensitive to substitution-in the case of the strongest para donor, MeNH-, this barrier increases to about 13 kcal · mol −1 . The trends in state energies as a function of substitution are rationalized using a (2,2) configuration interaction theory and qualitative molecular orbital theory. Analysis of spin-orbit coupling in the nitrenes using the same model in conjunction with explicit calculation of spin-orbit coupling matrix elements rationalizes why electron donating substituents increase rates of intersystem crossing.

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Section: Discussionmentioning

confidence: 85%

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

Johnson

Sullivan

Cramer³

2001

Int J of Quantum Chemistry

151

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“…As for CoP -, we carried out energy and geometry optimization calculations using the broken symmetry wave functions. [35][36][37][38][39] The thermal corrections to the Gibbs free energy are computed at 298.15 K. All the calculations were performed with Gaussian 09. 34 The standard one-electron redox potential relative to the reversible hydrogen electrode 5 (RHE) is computed by…”

Section: Computational Detailsmentioning

confidence: 99%

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts

Miyamoto

Asahi

2019

J. Phys. Chem. C

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Cobalt-porphyrin catalyzed reductive decomposition of CO 2 to CO is investigated based on the Koper's water facilitated CO 2 reduction mechanism using simple but accurate protocol based on thermodynamics. In our protocol, accurate predictions of standard redox potentials and free energy differences are achieved by combining strengths of both density functional theory and experimental observations. With the proposed protocol, we found that the proton transfer from H 2 O takes place at −0.80 V vs. RHE at pH=3 through a concerted pathway and, as a result, the key intermediate for the CO generation, i.e., [CoP−COOH]is formed. Since the redox potential of the proton transfer agrees well with experimentally observed CO 2 reduction potential, we successfully clarified that H 2 O plays an important role in the reductive decomposition of CO 2 to CO. This result is valuable not only for understanding the cobalt-porphyrin catalyzed reductive decomposition of CO 2 but also as a guide for the development of new catalysts.

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“…In view of this, we rely upon the smaller CAS and perform our perturbative calculations with the same. This additionally brings onto fore the fact that our method is effective enough in handling strongly corre- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 The 2,6-isomer of didehydropyridine (pyridyne) exhibits strong biradical character and thus its theoretical treatment remains a challenge until today 104,105,107,108,127,133,134 . Via this study we have also examined the effect of heteroatom incorporation into the m-benzyne.…”

Section: Ccsd(t) [Completely Renormalized Ccsd(t)] and Cr-cc(23) [Comentioning

confidence: 99%

Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory

et al. 2016

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Recently a state-specific multireference perturbation theory (SSMRPT) with an improved virtual orbitals complete active space configuration interaction (IVO-CASCI) reference function has been proposed for treating electronic structures of radicals such as methylene, m-benzyne, pyridyne, and pyridynium cation. This new development in MRPT, termed as IVO-SSMRPT, ensures that it is able to describe the structure of radicaloids with reasonable accuracy even with small reference spaces. IVO-SSMRPT is also capable of predicting the correct ordering of the lowest singlet-triplet gaps. Investigation of the first three electronic states of the oxygen molecule has also been used for rating our method. The agreement of our estimates with the available far more expensive benchmark state-of-the-art ab initio calculations is creditable. The IVO-SSMRPT method provides an effective avenue with manageable cost/accuracy ratio for accurately dealing with radicaloid systems possessing varying degrees of quasidegeneracy.

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Systematic comparison of the benzynes, pyridynes, and pyridynium cations and characterization of the Bergman cyclization of Z-but-1-en-3-yn-1-yl isonitrile to the meta diradical 2,4-pyridyne

Cited by 73 publications

References 74 publications

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts

Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory

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Systematic comparison of the benzynes, pyridynes, and pyridynium cations and characterization of the Bergman cyclization of Z-but-1-en-3-yn-1-yl isonitrile to the meta diradical 2,4-pyridyne

Cited by 73 publications

References 74 publications

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

meta and para substitution effects on the electronic state energies and ring‐expansion reactivities of phenylnitrenes

Water Facilitated Electrochemical Reduction of CO2 on Cobalt-Porphyrin Catalysts

Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory

Contact Info

Product

Resources

About

Water Facilitated Electrochemical Reduction of CO₂ on Cobalt-Porphyrin Catalysts