Determination of the interconversion energy barrier of three novel pentahelicene derivative enantiomers by dynamic high resolution liquid chromatography

- Enantioselective separation of enantiomers of three novel pentahelicene derivatives.
- Determination of kinetic and thermodynamic activation parameters of interconversion of pentahelicene derivatives.
- Dynamic high resolution liquid chromatography with variation of the column temperature, flow rate and deconvolution method were used.
- Determination of apparent enantiomerization energy barriers, enthalphy and entropy of the interconvertion was realized by deconvolution method.
- Parameters of energy barrier calculated from experiment were compared with theoretical values acquired from quantum mechanics calculation.

Dynamic high resolution liquid chromatography (DHPLC) was used to determine the kinetic and thermodynamic activation parameters of interconversion of three novel pentahelicene derivatives {3,5-bis(trifluoromethyl)benzo[i]pentahelicene, naphtho[1,2-i]pentahelicene and 4-methoxybenzo[i]pentahelicene}. DHPLC was performed on a chiral isopropyl − carbamate cyclofructan 6 (LARIHC CF6-P) column under normal phase conditions. Variation of the column temperature and flow rate was used to study the interconversion process. A computer assisted deconvolution method was employed to determine the individual peak areas and the retention times required for the calculation of apparent enantiomerization energy barriers, enthalphy and entropy of the interconvertion of above defined pentahelicene derivative enantiomers. An ab initio quantum chemistry method was used to estimate theoretical kinetic and thermodynamic interconversion parameters and to evaluate experimental data of these three novel pentahelicene derivative enantiomers.