Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋G＊＊ levels of theory. The relative ease ...Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋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 lendo 〉 2endo 〉 3endo.展开更多
文摘Topomerization of [9] annulen anion （1） and its 2-fluoro-, 2-chloro- and 2- bromo-defivatives （2, 3 and 4, respectively） are studied at the HF/6-31G＊ and B3LYP/6-31 1＋＋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 lendo 〉 2endo 〉 3endo.
