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DFT study of internal alkyne-to-disubstituted vinylidene isomerization in [CpRu(PhC≡CAr)(dppe)]+.
J Am Chem Soc. 2012 Oct 24; 134(42):17746-56.JA

Abstract

Internal alkyne-to-vinylidene isomerization in the Ru complexes ([CpRu(η(2)-PhC≡CC(6)H(4)R-p)(dppe)](+) (Cp = η(5)-C(5)H(5); dppe = Ph(2)PCH(2)CH(2)PPh(2); R = OMe, Cl, CO(2)Et)) has been investigated using a combination of quantum mechanics and molecular mechanics methods (QM/MM), such as ONIOM(B3PW91:UFF), and density functional theory (DFT) calculations. Three kinds of model systems (I-III), each having a different QM region for the ONIOM method, revealed that considering both the quantum effect of the substituent of the aryl group in the η(2)-alkyne ligand and that of the phenyl groups in the dppe ligand is essential for a correct understanding of this reaction. Several plausible mechanisms have been analyzed by using DFT calculations with the B3PW91 functional. It was found that the isomerization of three complexes (R = OMe, CO(2)Et, and Cl) proceeds via a direct 1,2-shift in all cases. The most favorable process in energy was path 3, which involves the orientation change of the alkyne ligand in the transition state. The activation energies were calculated to be 13.7, 15.0, and 16.4 kcal/mol, respectively, for the three complexes. Donor-acceptor analysis demonstrated that the aryl 1,2-shift is a nucleophilic reaction. Furthermore, our calculation results indicated that an electron-donating substituent on the aryl group stabilizes the positive charge on the accepting carbon rather than that on the migrating aryl group itself at the transition state. Therefore, unlike the general nucleophilic reaction, the less-electron-donating aryl group has an advantage in the migration.

Authors+Show Affiliations

Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22992130

Citation

Otsuka, Miho, et al. "DFT Study of Internal Alkyne-to-disubstituted Vinylidene Isomerization in [CpRu(PhC≡CAr)(dppe)]+." Journal of the American Chemical Society, vol. 134, no. 42, 2012, pp. 17746-56.
Otsuka M, Tsuchida N, Ikeda Y, et al. DFT study of internal alkyne-to-disubstituted vinylidene isomerization in [CpRu(PhC≡CAr)(dppe)]+. J Am Chem Soc. 2012;134(42):17746-56.
Otsuka, M., Tsuchida, N., Ikeda, Y., Kimura, Y., Mutoh, Y., Ishii, Y., & Takano, K. (2012). DFT study of internal alkyne-to-disubstituted vinylidene isomerization in [CpRu(PhC≡CAr)(dppe)]+. Journal of the American Chemical Society, 134(42), 17746-56. https://doi.org/10.1021/ja308018b
Otsuka M, et al. DFT Study of Internal Alkyne-to-disubstituted Vinylidene Isomerization in [CpRu(PhC≡CAr)(dppe)]+. J Am Chem Soc. 2012 Oct 24;134(42):17746-56. PubMed PMID: 22992130.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DFT study of internal alkyne-to-disubstituted vinylidene isomerization in [CpRu(PhC≡CAr)(dppe)]+. AU - Otsuka,Miho, AU - Tsuchida,Noriko, AU - Ikeda,Yousuke, AU - Kimura,Yusuke, AU - Mutoh,Yuichiro, AU - Ishii,Youichi, AU - Takano,Keiko, Y1 - 2012/10/10/ PY - 2012/9/21/entrez PY - 2012/9/21/pubmed PY - 2013/3/30/medline SP - 17746 EP - 56 JF - Journal of the American Chemical Society JO - J Am Chem Soc VL - 134 IS - 42 N2 - Internal alkyne-to-vinylidene isomerization in the Ru complexes ([CpRu(η(2)-PhC≡CC(6)H(4)R-p)(dppe)](+) (Cp = η(5)-C(5)H(5); dppe = Ph(2)PCH(2)CH(2)PPh(2); R = OMe, Cl, CO(2)Et)) has been investigated using a combination of quantum mechanics and molecular mechanics methods (QM/MM), such as ONIOM(B3PW91:UFF), and density functional theory (DFT) calculations. Three kinds of model systems (I-III), each having a different QM region for the ONIOM method, revealed that considering both the quantum effect of the substituent of the aryl group in the η(2)-alkyne ligand and that of the phenyl groups in the dppe ligand is essential for a correct understanding of this reaction. Several plausible mechanisms have been analyzed by using DFT calculations with the B3PW91 functional. It was found that the isomerization of three complexes (R = OMe, CO(2)Et, and Cl) proceeds via a direct 1,2-shift in all cases. The most favorable process in energy was path 3, which involves the orientation change of the alkyne ligand in the transition state. The activation energies were calculated to be 13.7, 15.0, and 16.4 kcal/mol, respectively, for the three complexes. Donor-acceptor analysis demonstrated that the aryl 1,2-shift is a nucleophilic reaction. Furthermore, our calculation results indicated that an electron-donating substituent on the aryl group stabilizes the positive charge on the accepting carbon rather than that on the migrating aryl group itself at the transition state. Therefore, unlike the general nucleophilic reaction, the less-electron-donating aryl group has an advantage in the migration. SN - 1520-5126 UR - https://www.unboundmedicine.com/medline/citation/22992130/DFT_study_of_internal_alkyne_to_disubstituted_vinylidene_isomerization_in_[CpRu_PhC≡CAr__dppe_]+_ L2 - https://doi.org/10.1021/ja308018b DB - PRIME DP - Unbound Medicine ER -