Ph. D. THESIS 2009

(mol·l -1 )
syn 8.8 x10 -3 1.4373 5.10 3.549
anti 8.8 x10 -3 0.69574 3.774 5.425
In equations (1) and (2) k1 and k-1 are the forward and reverse reaction rate
constants, K is the equilibrium constant, xe is the initial concentration of the
starting isomer, x is the concentration of the same isomer at the “t” time.
2.3.3. Chiral HPLC studies
In order to establish the chiral behavior of syn and anti isomers of compound
5, already separated by flash chromatography, a mixture of these isomers was
subjected to HPLC separation using a chiral stationary phase.
Figure 26. Chromatogram obtained during the chiral HPLC resolution of the mixture of
stereoisomers of compound 5.
The three separated peaks (Figure 37) correspond to the anti: tR1 = 12.443 min,
tR2 = 13.762 min and syn: tR3 = 15.011 min isomers.
The ratio syn/anti was found to be 71.80:28.19 (Table 10), which is in good
agreement with the value determined by 1 H-NMR investigations (73:27).
2.3.4. FT-IR study
The FT-IR investigations(Figure 27) of 5-syn and 5-anti in aprotic solvent (10.0
mM; CHCl3) in a large range of concentrations (from 10.0 mM to 0.156 mM)
revealed only absorption bands corresponding to the H bonds associated
molecules (υsyn = 3110/3202 cm -1 ; υanti = 3164/3295 cm -1 ). In order to break the
supramolecular structures tetrachloroethylene (C2Cl4) was used as aprotic and
non-polar solvent to evidence the presence of the monomer in FT-IR spectrum.
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