The X-ray structures of three potential molecular tweezers, C20H24N2O5 (1),
C20H20N6O13 (2) and C28H32N2O13 (3), differing only by the substituents on
the terminal aromatic moieties, display three as yet unreported arrays. Hy
drogen bonding with co-crystallized water molecules as well as van der Waal
s interactions between terminal aromatic moieties lead to specific packing
patterns, namely: (i) a membrane-like architecture of associated molecular
tapes in 1 . 2H(2)O, (ii) coupled right-handed and left-handed helices in 2
. H2O and (iii) a stepped arrangement provided by a back-to-back pairing i
n (3)(2) . H2O. Molecular modelling of individual molecules in vacuo shows
that the most stable conformers of 1-3 intrinsically display attractive int
eractions between the terminal aromatic groups, which stabilize a pseudocav
ity suitable for incorporation of a guest compound.