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Ab initio and DFT Study of Prototropic and Metallotropic 1,5-Shifts of Isolobal Cyclopentadienyl Derivatives


Affiliations
1 Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran, Islamic Republic of
2 Department of Chemistry, Hamadan Branch, Islamic Azad University, Hamadan, Iran, Islamic Republic of
3 Department of Chemistry, Shahr-e-Rey Branch, Islamic Azad University, Shahr-e-Rey, Iran, Islamic Republic of
 

The structures, energies and sigmatropic behaviour of η1-cyclopenta-2,4-dienylborane (1) and η1-cyclopentadiene-three carbonyl cobalt (I) (2) were examined using DFT-B3LYP/6-311+G** level of theory. Both BH2 and Co(CO)3 fragments in these compounds are isolobal. Results indicate that -BH2 and -Co(CO)3 in sigmatropic shifts had similar behaviour. Furthermore, in compounds 1 and 2, prototropic shifts have similar mechanisms. In compounds 1 and 2, metallotrotropic shift acts faster than prototropic shift. Migration of proton and Co(CO)3 took place through suprafacial [1,5]-sigmatropic mechanism, but -BH2 shift took place through antrafacial [1,3]-rearrangement. The barrier energies of prototropic shift in compounds 1 and 2 are 15.94 kcal mol-1 and 33.13 kcal mol-1 respectively. These energies are lower than those of brotropic shifts in compound 1 (0.16 kcal mol-1) or migration of CO(CO)3 in compound 2 (3.76 kcal mol-1).

Keywords

Ab initio, Cyclopentadienyl, Isolobal, Metallotropic, Prototropic, Sigmatropy.
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  • Ab initio and DFT Study of Prototropic and Metallotropic 1,5-Shifts of Isolobal Cyclopentadienyl Derivatives

Abstract Views: 594  |  PDF Views: 141

Authors

Zahra Javanshir
Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran, Islamic Republic of
Jameh-Bozorghi Saeed
Department of Chemistry, Hamadan Branch, Islamic Azad University, Hamadan, Iran, Islamic Republic of
Ali-Reza Namdari
Department of Chemistry, Shahr-e-Rey Branch, Islamic Azad University, Shahr-e-Rey, Iran, Islamic Republic of

Abstract


The structures, energies and sigmatropic behaviour of η1-cyclopenta-2,4-dienylborane (1) and η1-cyclopentadiene-three carbonyl cobalt (I) (2) were examined using DFT-B3LYP/6-311+G** level of theory. Both BH2 and Co(CO)3 fragments in these compounds are isolobal. Results indicate that -BH2 and -Co(CO)3 in sigmatropic shifts had similar behaviour. Furthermore, in compounds 1 and 2, prototropic shifts have similar mechanisms. In compounds 1 and 2, metallotrotropic shift acts faster than prototropic shift. Migration of proton and Co(CO)3 took place through suprafacial [1,5]-sigmatropic mechanism, but -BH2 shift took place through antrafacial [1,3]-rearrangement. The barrier energies of prototropic shift in compounds 1 and 2 are 15.94 kcal mol-1 and 33.13 kcal mol-1 respectively. These energies are lower than those of brotropic shifts in compound 1 (0.16 kcal mol-1) or migration of CO(CO)3 in compound 2 (3.76 kcal mol-1).

Keywords


Ab initio, Cyclopentadienyl, Isolobal, Metallotropic, Prototropic, Sigmatropy.



DOI: https://doi.org/10.18520/cs%2Fv112%2Fi04%2F743-749