Ph. D. THESIS 2009
Ph. D. THESIS 2009
Ph. D. THESIS 2009
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These investigations revealed the obtaining of associations of molecules which<br />
form spectacular supramolecular aggregates. The anti isomer gives a cyclic<br />
dimer by four hydrogen bonds (Figure 31).<br />
a<br />
b<br />
Figure 31. ORTEP diagram for the cyclic dimer of 5-anti (a : aRaR – aRaR ; b : aSaS<br />
– aSaS associations)<br />
The association of the molecules is homochiral and involves either aRaR (a)<br />
or aSaS (b) structures (the dimers are built up by highly selective enantiomeric<br />
recognition processes). The crystal is more or less a homogenous solution of<br />
the two enantiomeric dimers (it is a racemate).<br />
Syn isomer forms a supramolecular wheel via a cyclic trimer built up by six<br />
hydrogen bonds (Figure 32). Both analyzed structures exhibit a chain-chain<br />
conformation, according to the torsion angles values.<br />
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