Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma
Само за регистроване кориснике
2014
Аутори
Pitts, Amanda L.Wriglesworth, Alisdair
Sun, Xue-Zhong
Calladine, James A.
Zarić, Snežana D.
George, Michael W.
Hall, Michael B.
Чланак у часопису (Објављена верзија)
Метаподаци
Приказ свих података о документуАпстракт
Carbon-hydrogen bond activation reactions of four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) by the Cp'Rh(CO) fragments (Cp' = eta(5)-C5H5 (Cp) or eta(5)-C5Me5 (Cp*)) were modeled theoretically by combining density functional and coupled cluster theories, and their reaction rates were measured by fast time-resolved infrared spectroscopy. The reaction has two steps, starting with the formation of a a-complex intermediate, followed by oxidative addition of the C-H bond by the rhodium. A range of a-complex stabilities among the electronically unique C-H bonds in a cycloalkane were calculated and are related to the individual strengths of the C-H bond's interactions with the Rh fragment and the steric repulsion that is incurred upon forming the specific a-complex. The unexpectedly large increase in the lifetimes of the a-complexes from cyclohexane to cycloheptane was predicted to be due to the large range of stabilities of the different sigma-complexes found for cycloheptane.. The react...ion lifetimes were simulated with two mechanisms, with and without migrations among the different complexes, to determine if ring migrations prior to C-H activation were influencing the rate. Both mechanisms predicted similar lifetimes for cyclopentane, cyclohexane, and, to a lesser extent, cycloheptane, suggesting ring migrations do not have a large impact on the rate of C-H activation for these cycloalkanes. For cyclooctane, the inclusion of ring migrations in the reaction mechanism led to a more accurate prediction of the lifetime, indicating that ring migrations did have an effect on the rate of C-H activation for this alkane, and that migration among the a-complexes is faster than the C-H activation for this larger cycloalkane.
Извор:
Journal of the American Chemical Society, 2014, 136, 24, 8614-8625Издавач:
- Amer Chemical Soc, Washington
Финансирање / пројекти:
- Royal Society
- University of Nottingham
- National Science Foundation [CHE 0910552, 1300787]
Напомена:
- Supplementary material: http://cherry.chem.bg.ac.rs/handle/123456789/3685
DOI: 10.1021/ja5014773
ISSN: 0002-7863
PubMed: 24823385
WoS: 000337720200025
Scopus: 2-s2.0-84902687617
Колекције
Институција/група
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Pitts, Amanda L. AU - Wriglesworth, Alisdair AU - Sun, Xue-Zhong AU - Calladine, James A. AU - Zarić, Snežana D. AU - George, Michael W. AU - Hall, Michael B. PY - 2014 UR - https://cherry.chem.bg.ac.rs/handle/123456789/1792 AB - Carbon-hydrogen bond activation reactions of four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) by the Cp'Rh(CO) fragments (Cp' = eta(5)-C5H5 (Cp) or eta(5)-C5Me5 (Cp*)) were modeled theoretically by combining density functional and coupled cluster theories, and their reaction rates were measured by fast time-resolved infrared spectroscopy. The reaction has two steps, starting with the formation of a a-complex intermediate, followed by oxidative addition of the C-H bond by the rhodium. A range of a-complex stabilities among the electronically unique C-H bonds in a cycloalkane were calculated and are related to the individual strengths of the C-H bond's interactions with the Rh fragment and the steric repulsion that is incurred upon forming the specific a-complex. The unexpectedly large increase in the lifetimes of the a-complexes from cyclohexane to cycloheptane was predicted to be due to the large range of stabilities of the different sigma-complexes found for cycloheptane.. The reaction lifetimes were simulated with two mechanisms, with and without migrations among the different complexes, to determine if ring migrations prior to C-H activation were influencing the rate. Both mechanisms predicted similar lifetimes for cyclopentane, cyclohexane, and, to a lesser extent, cycloheptane, suggesting ring migrations do not have a large impact on the rate of C-H activation for these cycloalkanes. For cyclooctane, the inclusion of ring migrations in the reaction mechanism led to a more accurate prediction of the lifetime, indicating that ring migrations did have an effect on the rate of C-H activation for this alkane, and that migration among the a-complexes is faster than the C-H activation for this larger cycloalkane. PB - Amer Chemical Soc, Washington T2 - Journal of the American Chemical Society T1 - Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma VL - 136 IS - 24 SP - 8614 EP - 8625 DO - 10.1021/ja5014773 ER -
@article{ author = "Pitts, Amanda L. and Wriglesworth, Alisdair and Sun, Xue-Zhong and Calladine, James A. and Zarić, Snežana D. and George, Michael W. and Hall, Michael B.", year = "2014", abstract = "Carbon-hydrogen bond activation reactions of four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) by the Cp'Rh(CO) fragments (Cp' = eta(5)-C5H5 (Cp) or eta(5)-C5Me5 (Cp*)) were modeled theoretically by combining density functional and coupled cluster theories, and their reaction rates were measured by fast time-resolved infrared spectroscopy. The reaction has two steps, starting with the formation of a a-complex intermediate, followed by oxidative addition of the C-H bond by the rhodium. A range of a-complex stabilities among the electronically unique C-H bonds in a cycloalkane were calculated and are related to the individual strengths of the C-H bond's interactions with the Rh fragment and the steric repulsion that is incurred upon forming the specific a-complex. The unexpectedly large increase in the lifetimes of the a-complexes from cyclohexane to cycloheptane was predicted to be due to the large range of stabilities of the different sigma-complexes found for cycloheptane.. The reaction lifetimes were simulated with two mechanisms, with and without migrations among the different complexes, to determine if ring migrations prior to C-H activation were influencing the rate. Both mechanisms predicted similar lifetimes for cyclopentane, cyclohexane, and, to a lesser extent, cycloheptane, suggesting ring migrations do not have a large impact on the rate of C-H activation for these cycloalkanes. For cyclooctane, the inclusion of ring migrations in the reaction mechanism led to a more accurate prediction of the lifetime, indicating that ring migrations did have an effect on the rate of C-H activation for this alkane, and that migration among the a-complexes is faster than the C-H activation for this larger cycloalkane.", publisher = "Amer Chemical Soc, Washington", journal = "Journal of the American Chemical Society", title = "Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma", volume = "136", number = "24", pages = "8614-8625", doi = "10.1021/ja5014773" }
Pitts, A. L., Wriglesworth, A., Sun, X., Calladine, J. A., Zarić, S. D., George, M. W.,& Hall, M. B.. (2014). Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. in Journal of the American Chemical Society Amer Chemical Soc, Washington., 136(24), 8614-8625. https://doi.org/10.1021/ja5014773
Pitts AL, Wriglesworth A, Sun X, Calladine JA, Zarić SD, George MW, Hall MB. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. in Journal of the American Chemical Society. 2014;136(24):8614-8625. doi:10.1021/ja5014773 .
Pitts, Amanda L., Wriglesworth, Alisdair, Sun, Xue-Zhong, Calladine, James A., Zarić, Snežana D., George, Michael W., Hall, Michael B., "Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma" in Journal of the American Chemical Society, 136, no. 24 (2014):8614-8625, https://doi.org/10.1021/ja5014773 . .