ISMSC 2007 - Università degli Studi di Pavia

PSB 33
Multinuclear NMR, ESI MS and PM5 studies of a new derivative of Gossypol
with 2-thiophenecarbohydrazide as well as its complexes with monovalent
cations
P. Przybylski, R. Pankiewicz, W. Schilf, G. Schroeder, B. Brzezinski
Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland
Gossypol, a yellow pigment from cottonseeds, has drawn the attention of many scientists
because of its interesting physico-chemical properties as well as a number of biological and
medical applications. The main obstacle in the application of gossypol in medical therapy is its
relatively high toxicity evoked by the presence of two aldehyde groups in its molecule. The main
aim of our study is to search for such modifications of gossypol that would be characterised not
only by low toxicity but also high antibiotic activity related to the ability of complexation of
monovalent cations. For the purpose of our studies gossypol was extracted from cottonseeds
(Gossypium Herbaceum) and further converted into its new derivative with 2thiophenecarbohydrazide
(GHHT) [1].
O
S
N H
GHHT
H N
(N-imine-N-imine tautomer)
O H
H
O
O H
O
H O
H O
N H
H
N
H
S
O
The structure of GHHT and its complexes with Li + , Na + , K + , Rb + and Cs + cations have been
investigated by multinuclear NMR and PM5 methods. The stoichiometry of the complexes
formed between GHHT and monovalent cations was determined by the ESI MS method. The
structures of the complexes are stabilized by three types of intramolecular hydrogen bonds.
Derivatives of gossypol like its Schiff bases or hydrazones can occur in various tautomeric
forms [2-3]. The spectroscopic methods have provided clear evidence that GHHT and GHHT in
its complexes exist in the DMSO-d6 solution in the N-imine-N-imine tautomeric form. The
structures of the GHHT and its complexes with Li + , Na + , K + , Rb + , and Cs + cations were
visualized and discussed in details.
[1] P. Przybylski, W. Schilf, W. Lewandowska, B. Brzezinski, Biopolimers, 2006, 83, 213-225.
[2] P. Przybylski, G. Schroeder, B. Brzezinski, Phys. Chem. Chem. Phys., 2002, 4, 6137-6143.
[3] P. Przybylski, G. Schroeder, R. Pankiewicz, B. Brzezinski, F. Bartl, J. Mol. Struct., 2003, 658,
193-205.
Polycapsular assembly of exo-ditopic xylyl bridged bicalix[5]arenes with
long chained ,-alkanediammonium ions †
PSB 34
Yoram Cohen, a Sarit Slovak, a Giuseppe Gattuso, b Anna Notti, b Andrea Pappalardo, b
Melchiorre F. Parisi, b Ilenia Pisagatti, b Sebastiano Pappalardo c
a School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv
69978, Tel Aviv, Israel
b Dipartimento di Chimica Organica e Biologica, Università di Messina, Salita Sperone 31,
I-98166 Messina, Italy
c Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania,
Italy
The reversible and thermodynamically controlled construction of supramolecular assemblies
from couples of building blocks displaying complementary molecular affinities is a current
challenge in noncovalent synthesis. Supramolecular aggregates can be designed by choosing
topological features and/or chemical surfaces of the interconnecting modules, capable of
establishing a number of noncovalent intermolecular interactions typical of host–guest and
coordination chemistry. [1]
Among potential building blocks, calixarenes are especially attractive for their availability and
easy chemical alteration at both the wide and narrow rims. We have already shown that p-tertbutylcalix[5]arenes
in a fixed C5V cone-like arrangement form strong 1:1 inclusion complexes
with linear alkylammonium ions [2a] and discrete dimeric capsules in the presence of long
chained ,–alkanediammonium ions. [2b] Here we report that, when two such calix[5]arenes
are covalently linked via an o-, m-, or p-xylyl spacer at their lower rims as in 1, their cores
diverge and inclusion of suitable ,–alkanediammonium ions eventually results in the
formation of discrete bis-endo-cavity complexes and/or capsular assemblies along a polymer
chain, according to the length of the connector. [3] The assembly modes of 1 to
,–alkanediammonium ions have been ascertained by 1 H NMR spectroscopy, NMR diffusion
and ESI MS studies.
† This work was supported by MiUR (PRIN-2006 project).
[1] Supramolecular Polymers, 2 nd Edition, A. Ciferri Ed.; CRC Press, Boca Raton, FL. 2005.
[2] (a) F. Arnaud-Neu,S. Fuangswasdi, A. Notti, S. Pappalardo and M. F. Parisi, Angew Chem.,
Int. Ed. 1998, 37, 112–114; (b) D. Garozzo, F. H. Kohnke, P. Malvagna, A. Notti, S. Occhipinti,
S. Pappalardo, M. F. Parisi and I. Pisagatti, Tetrahedron Lett., 2002, 43, 7663–7667.
[3] For preliminary results, see: D. Garozzo, G. Gattuso, F. H. Kohnke, A. Notti, S. Pappalardo,
M. F. Parisi and I. Pisagatti, A. J. P. White and D. J. Williams, Org. Lett., 2003, 5, 4025–4028.