TY  - JOUR
AU  - Guan, Jia
AU  - Wriglesworth, Alisdair
AU  - Sun, Xue Zhong
AU  - Brothers, Edward N.
AU  - Zarić, Snežana D.
AU  - Evans, Meagan E.
AU  - Jones, William D.
AU  - Towrie, Michael
AU  - Hall, Michael B.
AU  - George, Michael W.
PY  - 2018
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/2893
AB  - Carbon-hydrogen bond activation of alkanes by Tp'Rh(CNR) (Tp' = Tp = trispyrazolylborate or Tp* = tris(3,5- dimethylpyrazolyl)borate) were followed by time-resolved infrared spectroscopy (TRIR) in the upsilon(CNR) and upsilon(B-H) spectral regions on Tp*Rh(CNCH2CMe3), and their reaction mechanisms were modeled by density functional theory (DFT) on TpRh(CNMe). The major intermediate species were: kappa(3)-eta(1)-alkane complex (1); kappa(2)-kappa(2)-alkane complex (2); and kappa(3)-alkyl hydride (3). Calculations predict that the barrier between 1 and 2 arises from a triplet-singlet crossing and intermediate 2 proceeds over the rate-determining C-H activation barrier to give the final product 3. The activation lifetimes measured for the Tp*Rh(CNR) and Tp*Rh(CO) fragments with n-heptane and four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) increase with alkanes size and show a dramatic increase between C6H12 and C7H14. A similar step-like behavior was observed previously with CpRh(CO) and Cp*Rh(CO) fragments and is attributed to the wider difference in C-H bonds that appear at C7H14. However, Tp'Rh(CNR) and Tp'Rh(CO) fragments have much longer absolute lifetimes compared to those of CpRh(CO) and Cp*Rh(CO) fragments, because the reduced electron density in dechelated kappa(2)-eta(2)-alkane Tp' complexes stabilizes the d(8) Rh(I) in a square-planar geometry and weakens the metal's ability for oxidative addition of the C-H bond. Further, the Tp'Rh(CNR) fragment has significantly slower rates of C-H activation in comparison to the Tp'Rh(CO) fragment for the larger cycloalkanes, because the steric bulk of the neopentyl isocyanide ligand hinders the rechelation in kappa(2)-Tp'Rh(CNR)(cycloalkane) species and results in the C-H activation without the assistance of the rechelation.
PB  - Amer Chemical Soc, Washington
T2  - Journal of the American Chemical Society
T1  - Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study
VL  - 140
IS  - 5
SP  - 1842
EP  - 1854
DO  - 10.1021/jacs.7b12152
ER  - 

@article{
author = "Guan, Jia and Wriglesworth, Alisdair and Sun, Xue Zhong and Brothers, Edward N. and Zarić, Snežana D. and Evans, Meagan E. and Jones, William D. and Towrie, Michael and Hall, Michael B. and George, Michael W.",
year = "2018",
abstract = "Carbon-hydrogen bond activation of alkanes by Tp'Rh(CNR) (Tp' = Tp = trispyrazolylborate or Tp* = tris(3,5- dimethylpyrazolyl)borate) were followed by time-resolved infrared spectroscopy (TRIR) in the upsilon(CNR) and upsilon(B-H) spectral regions on Tp*Rh(CNCH2CMe3), and their reaction mechanisms were modeled by density functional theory (DFT) on TpRh(CNMe). The major intermediate species were: kappa(3)-eta(1)-alkane complex (1); kappa(2)-kappa(2)-alkane complex (2); and kappa(3)-alkyl hydride (3). Calculations predict that the barrier between 1 and 2 arises from a triplet-singlet crossing and intermediate 2 proceeds over the rate-determining C-H activation barrier to give the final product 3. The activation lifetimes measured for the Tp*Rh(CNR) and Tp*Rh(CO) fragments with n-heptane and four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) increase with alkanes size and show a dramatic increase between C6H12 and C7H14. A similar step-like behavior was observed previously with CpRh(CO) and Cp*Rh(CO) fragments and is attributed to the wider difference in C-H bonds that appear at C7H14. However, Tp'Rh(CNR) and Tp'Rh(CO) fragments have much longer absolute lifetimes compared to those of CpRh(CO) and Cp*Rh(CO) fragments, because the reduced electron density in dechelated kappa(2)-eta(2)-alkane Tp' complexes stabilizes the d(8) Rh(I) in a square-planar geometry and weakens the metal's ability for oxidative addition of the C-H bond. Further, the Tp'Rh(CNR) fragment has significantly slower rates of C-H activation in comparison to the Tp'Rh(CO) fragment for the larger cycloalkanes, because the steric bulk of the neopentyl isocyanide ligand hinders the rechelation in kappa(2)-Tp'Rh(CNR)(cycloalkane) species and results in the C-H activation without the assistance of the rechelation.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of the American Chemical Society",
title = "Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study",
volume = "140",
number = "5",
pages = "1842-1854",
doi = "10.1021/jacs.7b12152"
}

Guan, J., Wriglesworth, A., Sun, X. Z., Brothers, E. N., Zarić, S. D., Evans, M. E., Jones, W. D., Towrie, M., Hall, M. B.,& George, M. W.. (2018). Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study. in Journal of the American Chemical Society
Amer Chemical Soc, Washington., 140(5), 1842-1854.
https://doi.org/10.1021/jacs.7b12152

Guan J, Wriglesworth A, Sun XZ, Brothers EN, Zarić SD, Evans ME, Jones WD, Towrie M, Hall MB, George MW. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study. in Journal of the American Chemical Society. 2018;140(5):1842-1854.
doi:10.1021/jacs.7b12152 .

Guan, Jia, Wriglesworth, Alisdair, Sun, Xue Zhong, Brothers, Edward N., Zarić, Snežana D., Evans, Meagan E., Jones, William D., Towrie, Michael, Hall, Michael B., George, Michael W., "Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study" in Journal of the American Chemical Society, 140, no. 5 (2018):1842-1854,
https://doi.org/10.1021/jacs.7b12152 . .

TY  - DATA
AU  - Guan, Jia
AU  - Wriglesworth, Alisdair
AU  - Sun, Xue Zhong
AU  - Brothers, Edward N.
AU  - Zarić, Snežana D.
AU  - Evans, Meagan E.
AU  - Jones, William D.
AU  - Towrie, Michael
AU  - Hall, Michael B.
AU  - George, Michael W.
PY  - 2018
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/2942
PB  - Amer Chemical Soc, Washington
T2  - Journal of the American Chemical Society
T1  - Supplementary data for the article: Guan, J.; Wriglesworth, A.; Sun, X. Z.; Brothers, E. N.; Zarić, S. D.; Evans, M. E.; Jones, W. D.; Towrie, M.; Hall, M. B.; George, M. W. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp′Rh(CNR)(Carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. Journal of the American Chemical Society 2018, 140 (5), 1842–1854. https://doi.org/10.1021/jacs.7b12152
UR  - https://hdl.handle.net/21.15107/rcub_cherry_2942
ER  - 

@misc{
author = "Guan, Jia and Wriglesworth, Alisdair and Sun, Xue Zhong and Brothers, Edward N. and Zarić, Snežana D. and Evans, Meagan E. and Jones, William D. and Towrie, Michael and Hall, Michael B. and George, Michael W.",
year = "2018",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of the American Chemical Society",
title = "Supplementary data for the article: Guan, J.; Wriglesworth, A.; Sun, X. Z.; Brothers, E. N.; Zarić, S. D.; Evans, M. E.; Jones, W. D.; Towrie, M.; Hall, M. B.; George, M. W. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp′Rh(CNR)(Carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. Journal of the American Chemical Society 2018, 140 (5), 1842–1854. https://doi.org/10.1021/jacs.7b12152",
url = "https://hdl.handle.net/21.15107/rcub_cherry_2942"
}

Guan, J., Wriglesworth, A., Sun, X. Z., Brothers, E. N., Zarić, S. D., Evans, M. E., Jones, W. D., Towrie, M., Hall, M. B.,& George, M. W.. (2018). Supplementary data for the article: Guan, J.; Wriglesworth, A.; Sun, X. Z.; Brothers, E. N.; Zarić, S. D.; Evans, M. E.; Jones, W. D.; Towrie, M.; Hall, M. B.; George, M. W. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp′Rh(CNR)(Carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. Journal of the American Chemical Society 2018, 140 (5), 1842–1854. https://doi.org/10.1021/jacs.7b12152. in Journal of the American Chemical Society
Amer Chemical Soc, Washington..
https://hdl.handle.net/21.15107/rcub_cherry_2942

Guan J, Wriglesworth A, Sun XZ, Brothers EN, Zarić SD, Evans ME, Jones WD, Towrie M, Hall MB, George MW. Supplementary data for the article: Guan, J.; Wriglesworth, A.; Sun, X. Z.; Brothers, E. N.; Zarić, S. D.; Evans, M. E.; Jones, W. D.; Towrie, M.; Hall, M. B.; George, M. W. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp′Rh(CNR)(Carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. Journal of the American Chemical Society 2018, 140 (5), 1842–1854. https://doi.org/10.1021/jacs.7b12152. in Journal of the American Chemical Society. 2018;.
https://hdl.handle.net/21.15107/rcub_cherry_2942 .

Guan, Jia, Wriglesworth, Alisdair, Sun, Xue Zhong, Brothers, Edward N., Zarić, Snežana D., Evans, Meagan E., Jones, William D., Towrie, Michael, Hall, Michael B., George, Michael W., "Supplementary data for the article: Guan, J.; Wriglesworth, A.; Sun, X. Z.; Brothers, E. N.; Zarić, S. D.; Evans, M. E.; Jones, W. D.; Towrie, M.; Hall, M. B.; George, M. W. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp′Rh(CNR)(Carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. Journal of the American Chemical Society 2018, 140 (5), 1842–1854. https://doi.org/10.1021/jacs.7b12152" in Journal of the American Chemical Society (2018),
https://hdl.handle.net/21.15107/rcub_cherry_2942 .

TY  - JOUR
AU  - Guan, Jia
AU  - Wriglesworth, Alisdair
AU  - Sun, Xue Zhong
AU  - Brothers, Edward N.
AU  - Zarić, Snežana D.
AU  - Evans, Meagan E.
AU  - Jones, William D.
AU  - Towrie, Michael
AU  - Hall, Michael B.
AU  - George, Michael W.
PY  - 2018
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/2091
AB  - Carbon-hydrogen bond activation of alkanes by Tp'Rh(CNR) (Tp' = Tp = trispyrazolylborate or Tp* = tris(3,5- dimethylpyrazolyl)borate) were followed by time-resolved infrared spectroscopy (TRIR) in the upsilon(CNR) and upsilon(B-H) spectral regions on Tp*Rh(CNCH2CMe3), and their reaction mechanisms were modeled by density functional theory (DFT) on TpRh(CNMe). The major intermediate species were: kappa(3)-eta(1)-alkane complex (1); kappa(2)-kappa(2)-alkane complex (2); and kappa(3)-alkyl hydride (3). Calculations predict that the barrier between 1 and 2 arises from a triplet-singlet crossing and intermediate 2 proceeds over the rate-determining C-H activation barrier to give the final product 3. The activation lifetimes measured for the Tp*Rh(CNR) and Tp*Rh(CO) fragments with n-heptane and four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) increase with alkanes size and show a dramatic increase between C6H12 and C7H14. A similar step-like behavior was observed previously with CpRh(CO) and Cp*Rh(CO) fragments and is attributed to the wider difference in C-H bonds that appear at C7H14. However, Tp'Rh(CNR) and Tp'Rh(CO) fragments have much longer absolute lifetimes compared to those of CpRh(CO) and Cp*Rh(CO) fragments, because the reduced electron density in dechelated kappa(2)-eta(2)-alkane Tp' complexes stabilizes the d(8) Rh(I) in a square-planar geometry and weakens the metal's ability for oxidative addition of the C-H bond. Further, the Tp'Rh(CNR) fragment has significantly slower rates of C-H activation in comparison to the Tp'Rh(CO) fragment for the larger cycloalkanes, because the steric bulk of the neopentyl isocyanide ligand hinders the rechelation in kappa(2)-Tp'Rh(CNR)(cycloalkane) species and results in the C-H activation without the assistance of the rechelation.
PB  - Amer Chemical Soc, Washington
T2  - Journal of the American Chemical Society
T1  - Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study
VL  - 140
IS  - 5
SP  - 1842
EP  - 1854
DO  - 10.1021/jacs.7b12152
ER  - 

@article{
author = "Guan, Jia and Wriglesworth, Alisdair and Sun, Xue Zhong and Brothers, Edward N. and Zarić, Snežana D. and Evans, Meagan E. and Jones, William D. and Towrie, Michael and Hall, Michael B. and George, Michael W.",
year = "2018",
abstract = "Carbon-hydrogen bond activation of alkanes by Tp'Rh(CNR) (Tp' = Tp = trispyrazolylborate or Tp* = tris(3,5- dimethylpyrazolyl)borate) were followed by time-resolved infrared spectroscopy (TRIR) in the upsilon(CNR) and upsilon(B-H) spectral regions on Tp*Rh(CNCH2CMe3), and their reaction mechanisms were modeled by density functional theory (DFT) on TpRh(CNMe). The major intermediate species were: kappa(3)-eta(1)-alkane complex (1); kappa(2)-kappa(2)-alkane complex (2); and kappa(3)-alkyl hydride (3). Calculations predict that the barrier between 1 and 2 arises from a triplet-singlet crossing and intermediate 2 proceeds over the rate-determining C-H activation barrier to give the final product 3. The activation lifetimes measured for the Tp*Rh(CNR) and Tp*Rh(CO) fragments with n-heptane and four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) increase with alkanes size and show a dramatic increase between C6H12 and C7H14. A similar step-like behavior was observed previously with CpRh(CO) and Cp*Rh(CO) fragments and is attributed to the wider difference in C-H bonds that appear at C7H14. However, Tp'Rh(CNR) and Tp'Rh(CO) fragments have much longer absolute lifetimes compared to those of CpRh(CO) and Cp*Rh(CO) fragments, because the reduced electron density in dechelated kappa(2)-eta(2)-alkane Tp' complexes stabilizes the d(8) Rh(I) in a square-planar geometry and weakens the metal's ability for oxidative addition of the C-H bond. Further, the Tp'Rh(CNR) fragment has significantly slower rates of C-H activation in comparison to the Tp'Rh(CO) fragment for the larger cycloalkanes, because the steric bulk of the neopentyl isocyanide ligand hinders the rechelation in kappa(2)-Tp'Rh(CNR)(cycloalkane) species and results in the C-H activation without the assistance of the rechelation.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of the American Chemical Society",
title = "Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study",
volume = "140",
number = "5",
pages = "1842-1854",
doi = "10.1021/jacs.7b12152"
}

Guan, J., Wriglesworth, A., Sun, X. Z., Brothers, E. N., Zarić, S. D., Evans, M. E., Jones, W. D., Towrie, M., Hall, M. B.,& George, M. W.. (2018). Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study. in Journal of the American Chemical Society
Amer Chemical Soc, Washington., 140(5), 1842-1854.
https://doi.org/10.1021/jacs.7b12152

Guan J, Wriglesworth A, Sun XZ, Brothers EN, Zarić SD, Evans ME, Jones WD, Towrie M, Hall MB, George MW. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study. in Journal of the American Chemical Society. 2018;140(5):1842-1854.
doi:10.1021/jacs.7b12152 .

Guan, Jia, Wriglesworth, Alisdair, Sun, Xue Zhong, Brothers, Edward N., Zarić, Snežana D., Evans, Meagan E., Jones, William D., Towrie, Michael, Hall, Michael B., George, Michael W., "Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time Resolved Infrared Spectroscopic Study" in Journal of the American Chemical Society, 140, no. 5 (2018):1842-1854,
https://doi.org/10.1021/jacs.7b12152 . .

TY  - DATA
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/123456789/3685
PB  - Amer Chemical Soc, Washington
T2  - Journal of the American Chemical Society
T1  - Supplementary data for the article: Pitts, A. L.; Wriglesworth, A.; Sun, X.-Z.; Calladine, J. A.; Zarić, S. D.; George, M. W.; Hall, M. B. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. Journal of the American Chemical Society 2014, 136 (24), 8614–8625. https://doi.org/10.1021/ja5014773
UR  - https://hdl.handle.net/21.15107/rcub_cherry_3685
ER  - 

@misc{
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",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of the American Chemical Society",
title = "Supplementary data for the article: Pitts, A. L.; Wriglesworth, A.; Sun, X.-Z.; Calladine, J. A.; Zarić, S. D.; George, M. W.; Hall, M. B. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. Journal of the American Chemical Society 2014, 136 (24), 8614–8625. https://doi.org/10.1021/ja5014773",
url = "https://hdl.handle.net/21.15107/rcub_cherry_3685"
}

Pitts, A. L., Wriglesworth, A., Sun, X., Calladine, J. A., Zarić, S. D., George, M. W.,& Hall, M. B.. (2014). Supplementary data for the article: Pitts, A. L.; Wriglesworth, A.; Sun, X.-Z.; Calladine, J. A.; Zarić, S. D.; George, M. W.; Hall, M. B. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. Journal of the American Chemical Society 2014, 136 (24), 8614–8625. https://doi.org/10.1021/ja5014773. in Journal of the American Chemical Society
Amer Chemical Soc, Washington..
https://hdl.handle.net/21.15107/rcub_cherry_3685

Pitts AL, Wriglesworth A, Sun X, Calladine JA, Zarić SD, George MW, Hall MB. Supplementary data for the article: Pitts, A. L.; Wriglesworth, A.; Sun, X.-Z.; Calladine, J. A.; Zarić, S. D.; George, M. W.; Hall, M. B. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. Journal of the American Chemical Society 2014, 136 (24), 8614–8625. https://doi.org/10.1021/ja5014773. in Journal of the American Chemical Society. 2014;.
https://hdl.handle.net/21.15107/rcub_cherry_3685 .

Pitts, Amanda L., Wriglesworth, Alisdair, Sun, Xue-Zhong, Calladine, James A., Zarić, Snežana D., George, Michael W., Hall, Michael B., "Supplementary data for the article: Pitts, A. L.; Wriglesworth, A.; Sun, X.-Z.; Calladine, J. A.; Zarić, S. D.; George, M. W.; Hall, M. B. Carbon-Hydrogen Activation of Cycloalkanes by Cyclopentadienylcarbonylrhodium-A Lifetime Enigma. Journal of the American Chemical Society 2014, 136 (24), 8614–8625. https://doi.org/10.1021/ja5014773" in Journal of the American Chemical Society (2014),
https://hdl.handle.net/21.15107/rcub_cherry_3685 .

TY  - 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 . .

TY  - JOUR
AU  - George, Michael W.
AU  - Hall, Michael B.
AU  - Jina, Omar S.
AU  - Portius, Peter
AU  - Sun, Xue-Zhong
AU  - Towrie, Michael
AU  - Wu, Hong
AU  - Yang, Xinzheng
AU  - Zarić, Snežana D.
PY  - 2010
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/1136
AB  - Fast time-resolved infrared spectroscopic measurements have allowed precise determination of the rates of activation of alkanes by Cp'Rh(CO) (Cp' = eta(5)-C5H5 or eta(5)-C5Me5). We have monitored the kinetics of C-H activation in solution at room temperature and determined how the change in rate of oxidative cleavage varies from methane to decane. The lifetime of CpRh(CO)(alkane) shows a nearly linear behavior with respect to the length of the alkane chain, whereas the related Cp*Rh(CO)(alkane) has clear oscillatory behavior upon changing the alkane. Coupled cluster and density functional theory calculations on these complexes, transition states, and intermediates provide the insight into the mechanism and barriers in order to develop a kinetic simulation of the experimental results. The observed behavior is a subtle interplay between the rates of activation and migration. Unexpectedly, the calculations predict that the most rapid process in these Cp'Rh (CO)(alkane) systems is the 1,3-migration along the alkane chain. The linear behavior in the observed lifetime of CpRh(CO)(alkane) results from a mechanism in which the next most rapid process is the activation of primary C-H bonds (-CH3 groups), while the third key step in this system is 1,2-migration with a slightly slower rate. The oscillatory behavior in the lifetime of Cp*Rh(CO)(alkane) with respect to the alkane's chain length follows from subtle interplay between more rapid migrations and less rapid primary C-H activation, with respect to CpRh(CO)(alkane), especially when the CH3 group is near a gauche turn. This interplay results in the activation being controlled by the percentage of alkane conformers.
PB  - Natl Acad Sciences, Washington
T2  - Proceedings of the National Academy of Sciences of the United States
T1  - Understanding the factors affecting the activation of alkane by Cp ' Rh(CO)(2) (Cp ' = Cp or Cp*)
VL  - 107
IS  - 47
SP  - 20178
EP  - 20183
DO  - 10.1073/pnas.1001249107
ER  - 

@article{
author = "George, Michael W. and Hall, Michael B. and Jina, Omar S. and Portius, Peter and Sun, Xue-Zhong and Towrie, Michael and Wu, Hong and Yang, Xinzheng and Zarić, Snežana D.",
year = "2010",
abstract = "Fast time-resolved infrared spectroscopic measurements have allowed precise determination of the rates of activation of alkanes by Cp'Rh(CO) (Cp' = eta(5)-C5H5 or eta(5)-C5Me5). We have monitored the kinetics of C-H activation in solution at room temperature and determined how the change in rate of oxidative cleavage varies from methane to decane. The lifetime of CpRh(CO)(alkane) shows a nearly linear behavior with respect to the length of the alkane chain, whereas the related Cp*Rh(CO)(alkane) has clear oscillatory behavior upon changing the alkane. Coupled cluster and density functional theory calculations on these complexes, transition states, and intermediates provide the insight into the mechanism and barriers in order to develop a kinetic simulation of the experimental results. The observed behavior is a subtle interplay between the rates of activation and migration. Unexpectedly, the calculations predict that the most rapid process in these Cp'Rh (CO)(alkane) systems is the 1,3-migration along the alkane chain. The linear behavior in the observed lifetime of CpRh(CO)(alkane) results from a mechanism in which the next most rapid process is the activation of primary C-H bonds (-CH3 groups), while the third key step in this system is 1,2-migration with a slightly slower rate. The oscillatory behavior in the lifetime of Cp*Rh(CO)(alkane) with respect to the alkane's chain length follows from subtle interplay between more rapid migrations and less rapid primary C-H activation, with respect to CpRh(CO)(alkane), especially when the CH3 group is near a gauche turn. This interplay results in the activation being controlled by the percentage of alkane conformers.",
publisher = "Natl Acad Sciences, Washington",
journal = "Proceedings of the National Academy of Sciences of the United States",
title = "Understanding the factors affecting the activation of alkane by Cp ' Rh(CO)(2) (Cp ' = Cp or Cp*)",
volume = "107",
number = "47",
pages = "20178-20183",
doi = "10.1073/pnas.1001249107"
}

George, M. W., Hall, M. B., Jina, O. S., Portius, P., Sun, X., Towrie, M., Wu, H., Yang, X.,& Zarić, S. D.. (2010). Understanding the factors affecting the activation of alkane by Cp ' Rh(CO)(2) (Cp ' = Cp or Cp*). in Proceedings of the National Academy of Sciences of the United States
Natl Acad Sciences, Washington., 107(47), 20178-20183.
https://doi.org/10.1073/pnas.1001249107

George MW, Hall MB, Jina OS, Portius P, Sun X, Towrie M, Wu H, Yang X, Zarić SD. Understanding the factors affecting the activation of alkane by Cp ' Rh(CO)(2) (Cp ' = Cp or Cp*). in Proceedings of the National Academy of Sciences of the United States. 2010;107(47):20178-20183.
doi:10.1073/pnas.1001249107 .

George, Michael W., Hall, Michael B., Jina, Omar S., Portius, Peter, Sun, Xue-Zhong, Towrie, Michael, Wu, Hong, Yang, Xinzheng, Zarić, Snežana D., "Understanding the factors affecting the activation of alkane by Cp ' Rh(CO)(2) (Cp ' = Cp or Cp*)" in Proceedings of the National Academy of Sciences of the United States, 107, no. 47 (2010):20178-20183,
https://doi.org/10.1073/pnas.1001249107 . .