In this study, the enantioseparation of fourteen planar chiral ferrocenes containing halogen atoms, and methyl, iodoethynyl, phenyl and 2-naphthyl groups, as substituents, was explored with a cellulose tris(4-methylbenzoate) (CMB)-based chiral column under multimodal elution conditions. n-Hexane/2-propanol (2-PrOH) 95:5 v/v, pure methanol (MeOH), and MeOH/water 90:10 v/v were used as mobile phases (MPs). With CMB, baseline enantioseparations were achieved for nine analytes with separation factors (alfa) ranging from 1.24 to 1.77, whereas only three analytes could be enantioseparated with 1.14 <= alfa <= 1.51 on a cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC)-based column, used as a reference for comparison, under the same elution conditions. Pendant group-dependent reversal of the enantiomer elution order (EEO) was observed in several cases by changing CMB to CDMPC. The impact of analyte and CSP structure, and MP polarity on the enantioseparation was evaluated. The two cellulose-based CSPs featured by different pendant groups were also compared in terms of thermodynamics. For this purpose, enthalpy (deltaH°), entropy (deltaS°) and free energy (deltaG°) differences, isoenantioselective temperatures (Tiso) and enthalpy/entropy ratios (Q), associated with the enantioseparations, were derived from van 't Hoff plots by using n-hexane/2-propanol 95:5 v/v and methanol/water 90:10 v/v as MPs. With the aim to disclose the functions of the different substituents in mechanisms and noncovalent interactions underlying analyte-selector complex formation at molecular level, electrostatic potential (V) analysis and molecular dynamics (MD) simulations were used as computational techniques. On this basis, enantioseparations and related mechanisms were investigated by integrating theoretical and experimental data.
Enantioseparation of planar chiral ferrocenes on cellulose-based chiral stationary phases: Benzoate versus carbamate pendant groups
Roberto Dallocchio;Alessandro Dessì;Barbara Sechi;Paola Peluso
2023
Abstract
In this study, the enantioseparation of fourteen planar chiral ferrocenes containing halogen atoms, and methyl, iodoethynyl, phenyl and 2-naphthyl groups, as substituents, was explored with a cellulose tris(4-methylbenzoate) (CMB)-based chiral column under multimodal elution conditions. n-Hexane/2-propanol (2-PrOH) 95:5 v/v, pure methanol (MeOH), and MeOH/water 90:10 v/v were used as mobile phases (MPs). With CMB, baseline enantioseparations were achieved for nine analytes with separation factors (alfa) ranging from 1.24 to 1.77, whereas only three analytes could be enantioseparated with 1.14 <= alfa <= 1.51 on a cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC)-based column, used as a reference for comparison, under the same elution conditions. Pendant group-dependent reversal of the enantiomer elution order (EEO) was observed in several cases by changing CMB to CDMPC. The impact of analyte and CSP structure, and MP polarity on the enantioseparation was evaluated. The two cellulose-based CSPs featured by different pendant groups were also compared in terms of thermodynamics. For this purpose, enthalpy (deltaH°), entropy (deltaS°) and free energy (deltaG°) differences, isoenantioselective temperatures (Tiso) and enthalpy/entropy ratios (Q), associated with the enantioseparations, were derived from van 't Hoff plots by using n-hexane/2-propanol 95:5 v/v and methanol/water 90:10 v/v as MPs. With the aim to disclose the functions of the different substituents in mechanisms and noncovalent interactions underlying analyte-selector complex formation at molecular level, electrostatic potential (V) analysis and molecular dynamics (MD) simulations were used as computational techniques. On this basis, enantioseparations and related mechanisms were investigated by integrating theoretical and experimental data.File | Dimensione | Formato | |
---|---|---|---|
2023_Electrophoresis_Article.pdf
solo utenti autorizzati
Descrizione: Enantioseparation of planar chiral ferrocenes on cellulose-based chiral stationary phases: benzoate versus carbamate pendant groups
Tipologia:
Versione Editoriale (PDF)
Licenza:
NON PUBBLICO - Accesso privato/ristretto
Dimensione
1.91 MB
Formato
Adobe PDF
|
1.91 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
2023 Electrophoresis_Article_Accepted Manuscript.pdf
Open Access dal 14/10/2023
Descrizione: Enantioseparation of planar chiral ferrocenes on cellulose-based chiral stationary phases: benzoate versus carbamate pendant groups
Tipologia:
Documento in Post-print
Licenza:
Creative commons
Dimensione
476.44 kB
Formato
Adobe PDF
|
476.44 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.