Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control
Samo za registrovane korisnike
2017
Autori
Ninković, DraganMoncho, S.
Petrović, Predrag
Zarić, Snežana D.
Hall, Michael B.
Brothers, Edward N.
Članak u časopisu (Objavljena verzija)
Metapodaci
Prikaz svih podataka o dokumentuApstrakt
The titanium neopentylidene complex (PNP)Ti=CHtBu(CH2 tBu) (PNP = N[2-PiPr2-4-methylphenyl]2-) is capable of activating both sp2 and sp3 C-H bonds under mild conditions. In addition to methane C-H activation, competition between the initial hydrogen abstraction reaction to form the methane activation product and the tautomerization reaction of this product to form a terminal methylidene was also explored. Several modifications of the PNP and CHtBu ligands were explored to determine the effect of these changes on C-H bond activation. In general, on the one hand, the modifications involving electronic effects have small and inconsistent influence on the stability of the intermediates and products and on the reaction barriers. On the other hand, the use of bulky groups in the ligands favors the methane activation process. By replacing the iPr groups in the PNP ligand with tBu groups, both methane activation and tautomerization reactions become more energetically favorable than in the unmo...dified complex. On the one hand, the largest acceleration of the methane C-H activation occurs when tBu groups in the phosphine are combined with an extra CH2 linker between the aromatic ring and the phosphine. On the other hand, replacing the nitrogen in the PNP ligand by phosphorus results in lower barriers for the tautomerization reaction and the stabilization of the product of the tautomerization although it remains slightly less stable than product of methane C-H activation. While several ligand modifications related to the electronic effects were examined, it is interesting that most of them did not make a significant change on the barriers for either reaction, indicating a significant resilience of this titanium complex, which could be used to enhance the practical aspects of the complex without a significant loss of its activity.
Izvor:
Inorganic Chemistry, 2017, 56, 15, 9264-9272Izdavač:
- ACS Publications
Finansiranje / projekti:
- NPRP Grant No. 7-297-1-051 from the Qatar National Research Fund (a member of the Qatar Foundation)
Napomena:
- Supplementary material: http://cherry.chem.bg.ac.rs/handle/123456789/3228
DOI: 10.1021/acs.inorgchem.7b01340
ISSN: 0020-1669
WoS: 000407405500074
Scopus: 2-s2.0-85026995872
Institucija/grupa
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Ninković, Dragan AU - Moncho, S. AU - Petrović, Predrag AU - Zarić, Snežana D. AU - Hall, Michael B. AU - Brothers, Edward N. PY - 2017 UR - https://cherry.chem.bg.ac.rs/handle/123456789/317 AB - The titanium neopentylidene complex (PNP)Ti=CHtBu(CH2 tBu) (PNP = N[2-PiPr2-4-methylphenyl]2-) is capable of activating both sp2 and sp3 C-H bonds under mild conditions. In addition to methane C-H activation, competition between the initial hydrogen abstraction reaction to form the methane activation product and the tautomerization reaction of this product to form a terminal methylidene was also explored. Several modifications of the PNP and CHtBu ligands were explored to determine the effect of these changes on C-H bond activation. In general, on the one hand, the modifications involving electronic effects have small and inconsistent influence on the stability of the intermediates and products and on the reaction barriers. On the other hand, the use of bulky groups in the ligands favors the methane activation process. By replacing the iPr groups in the PNP ligand with tBu groups, both methane activation and tautomerization reactions become more energetically favorable than in the unmodified complex. On the one hand, the largest acceleration of the methane C-H activation occurs when tBu groups in the phosphine are combined with an extra CH2 linker between the aromatic ring and the phosphine. On the other hand, replacing the nitrogen in the PNP ligand by phosphorus results in lower barriers for the tautomerization reaction and the stabilization of the product of the tautomerization although it remains slightly less stable than product of methane C-H activation. While several ligand modifications related to the electronic effects were examined, it is interesting that most of them did not make a significant change on the barriers for either reaction, indicating a significant resilience of this titanium complex, which could be used to enhance the practical aspects of the complex without a significant loss of its activity. PB - ACS Publications T2 - Inorganic Chemistry T1 - Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control VL - 56 IS - 15 SP - 9264 EP - 9272 DO - 10.1021/acs.inorgchem.7b01340 ER -
@article{ author = "Ninković, Dragan and Moncho, S. and Petrović, Predrag and Zarić, Snežana D. and Hall, Michael B. and Brothers, Edward N.", year = "2017", abstract = "The titanium neopentylidene complex (PNP)Ti=CHtBu(CH2 tBu) (PNP = N[2-PiPr2-4-methylphenyl]2-) is capable of activating both sp2 and sp3 C-H bonds under mild conditions. In addition to methane C-H activation, competition between the initial hydrogen abstraction reaction to form the methane activation product and the tautomerization reaction of this product to form a terminal methylidene was also explored. Several modifications of the PNP and CHtBu ligands were explored to determine the effect of these changes on C-H bond activation. In general, on the one hand, the modifications involving electronic effects have small and inconsistent influence on the stability of the intermediates and products and on the reaction barriers. On the other hand, the use of bulky groups in the ligands favors the methane activation process. By replacing the iPr groups in the PNP ligand with tBu groups, both methane activation and tautomerization reactions become more energetically favorable than in the unmodified complex. On the one hand, the largest acceleration of the methane C-H activation occurs when tBu groups in the phosphine are combined with an extra CH2 linker between the aromatic ring and the phosphine. On the other hand, replacing the nitrogen in the PNP ligand by phosphorus results in lower barriers for the tautomerization reaction and the stabilization of the product of the tautomerization although it remains slightly less stable than product of methane C-H activation. While several ligand modifications related to the electronic effects were examined, it is interesting that most of them did not make a significant change on the barriers for either reaction, indicating a significant resilience of this titanium complex, which could be used to enhance the practical aspects of the complex without a significant loss of its activity.", publisher = "ACS Publications", journal = "Inorganic Chemistry", title = "Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control", volume = "56", number = "15", pages = "9264-9272", doi = "10.1021/acs.inorgchem.7b01340" }
Ninković, D., Moncho, S., Petrović, P., Zarić, S. D., Hall, M. B.,& Brothers, E. N.. (2017). Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control. in Inorganic Chemistry ACS Publications., 56(15), 9264-9272. https://doi.org/10.1021/acs.inorgchem.7b01340
Ninković D, Moncho S, Petrović P, Zarić SD, Hall MB, Brothers EN. Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control. in Inorganic Chemistry. 2017;56(15):9264-9272. doi:10.1021/acs.inorgchem.7b01340 .
Ninković, Dragan, Moncho, S., Petrović, Predrag, Zarić, Snežana D., Hall, Michael B., Brothers, Edward N., "Methane Activations by Titanium Neopentylidene Complexes: Electronic Resilience and Steric Control" in Inorganic Chemistry, 56, no. 15 (2017):9264-9272, https://doi.org/10.1021/acs.inorgchem.7b01340 . .