International Summer School PROGRAM - Laboratoire d'Infochimie ...

Synthesis and Investigations of Multiple Hydrogen Bonded
Supramolecular Host - Guest Complexes
Philipp Otte,
Ulrich Lüning*
Otto-Diels-Institut für Organische Chemie, Olshausenstraße 40, 24098 Kiel, GER.
potte@oc.uni-kiel.de, luening@oc.uni-kiel.de
In supramolecular chemistry, molecular recognition via non-covalent binding sites
such as hydrogen bonds is common. It is necessary to have complementary hydrogen
bond acceptor (A) and hydrogen donor (D) patterns. A single hydrogen bond is
relatively weak, but the combination of multiple hydrogen bonds can lead to stable
host - guest complexes. [1]
nBu
O
N
H
O
nBu
N N
H H
N N
N H N
CN
O
N
H
O
R
nBu
R = (CH 2CH 2O) 3OEt
nBu
N
H
X
N N N R
H
H
H
N N N O
O
H3C CH 3
X = O, S
R = CO(CH2CH2O) 3Et
(CO)CH3 H
It is reasonable to synthesize molecules whose preferred conformation is the one
which can form the highest number of hydrogen bonds. If an intramolecular bond has to
be broken to get the needed binding pattern, a loss of energy at the expense of the
complex stability would be the consequence. [2] Therefore, the aim should be to stabilize
[3]
the preferred conformation by using, for example, intramolecular hydrogen bonds.
nBu
N
H
X
N N N R
H
H
H
X
N
N
X = O, S nBu
R = CO(CH2CH2O) 3Et
N N R
H
Due to the orthogonality of the binding sites, highly specific dendrimeric systems
could be generated.
[1] J. Taubitz, U. Lüning, Eur. J. Org. Chem. 2008, 5922-5927.
[2] S. Brammer, U. Lüning, C. Kühl, Eur. J. Org. Chem. 2002, 4054-4062.
[3] E.W. Meijer et al. Science 1997, 278, 1601-1604.
H
nBu
N
H
O
H
N
H
N
CH 3
N
O