Ph. D. THESIS 2009

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