Determination of the interconversion energy barrier of three novel pentahelicene derivative enantiomers by dynamic high resolution liquid chromatography.
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.
Institute of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia. Electronic address: pavel.majek@stuba.sk.
Pavel
P
Majek
Institute of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia.
Jan
J
Krupcik
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA.
Zachary S
ZS
Breitbach
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA.
Milan K
MK
Dissanayake
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA.
Peter
P
Kroll
Department of Chemistry, University of North Texas, Denton, TX, USA.
Aaron A
AA
Ruch
Department of Chemistry, University of North Texas, Denton, TX, USA.
LeGrande M
LM
Slaughter
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA.
Daniel W
DW
Armstrong
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007700:Kinetics; D008958:Models, Molecular; D011083:Polycyclic Compounds / Q000737:chemistry* / Q000302:isolation & purification; D013237:Stereoisomerism; D013816:Thermodynamics
D011083:Polycyclic Compounds; C031660:helicenes
Dynamic high performance liquid chromatography; Enantioselective separation; Interconversion of pentahelicene derivatives; Thermodynamic activation parameters