Topomerization of 2-Halo-[9] Annulen Anion at the DFT Level

• 作 者: SATTAR Arshadi AHMADREZA Bekhradnia
• 机 构: Department of Chemistry,Payame Noor University,Pharmaceutical Sciences Research Center,Department of
• 出 处: 结构化学
• 发表日期: 2011年10期
• 关键词: substituent unstable anion fluoro bromo membered chloro keyword convert rings

Topomerization of [9] annulen anion(1)and its 2-fluoro-,2-chloro-and 2-bromo-derivatives(2,3 and 4,respectively)are studied at the HF/6-31G* and B3LYP/6-311++G** levels of theory.The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent.Consequently,the endo-2-halo-[9] annulen anion topomers become unstable and easily convert to related exo-topomers.Hence,according to the DFT calcu-lations,the order of topomerization energy barrier for endo exo topomerization is 1endo > 2 endo > 3endo.

Topomerization of [9] annulen anion (1) and its 2-fluoro-, 2-chloro-and 2-bromo- derivatives (2,3 and 4, respectively) were studied at the HF / 6-31G * and B3LYP / 6 -311 ++ G ** levels of theory. The relative ease of topomerization is dependent on the charge distribution and planarity of the ground state and the transition state of 9-membered rings as well as the size and electronegativity of halogen substituent. Reconstructed, the endo-2-halo- [9] annulen anion topomers become unstable and easily convert to related exo-topomers .ence, according to the DFT calcu-lations, the order of topomerization energy barrier for endo exo topomerization is 1endo> 2 endo> 3endo.