Russian Chemical Bulletin, International Edition, Vol. 58, No. 6, pp. 1211—1216, June, 2009 1211
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1179—1184, June, 2009.
10665285/09/58061211 © 2009 Springer Science+Business Media, Inc.
Stereospecific [2+2] autophotocycloaddition in the dimeric complex
of 18crown6 ether styryl dye bearing
N(3ammoniopropyl) substituent*
S. P. Gromov,
a
N. A. Lobova,
a
A. I. Vedernikov,
a
L. G. Kuz´mina,
b
J. A. K. Howard,
c
and M. V. Alfimov
a
a
Photochemistry Center, Russian Academy of Sciences,
7A ul. Novatorov, 119421 Moscow, Russian Federation.
Fax: +7 (495) 936 1255. Email: gromov@photonics.ru
b
N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
31 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (495) 954 1279
c
Department of Chemistry, University of Durham,
South Road, Durham DH1 3LE, UK
New 18crown6 ether styryl dye of the 4pyridine series bearing N(3ammoniopropyl)
substituent has been synthesized. In MeCN, the dye forms a stable dimeric complex of the
synheadtotail type due to the complexation of the ammonium group of one molecule
with the crown ether fragment of another. In the dimeric complex, the ethylene bonds of
the molecules are close in space and antiparallel, which promotes an efficient stereospecific
[2+2] autophotocycloaddition to yield the only rcttisomer of 1,2,3,4tetrasubstituted
cyclobutane. The cyclobutane derivative structure was confirmed by NMR spectroscopy and
Xray diffraction.
Key words: styryl dyes, crown ethers, ammonium ions, complexation, [2+2] photo
cycloaddition, cyclobutanes.
In the last two decades, intensive development of
supramolecular chemistry is due to the research on pro
spective methods for selforganization of organic mol
ecules (building blocks) in solution or in solid phase using
various weak (noncovalent) interactions.
1,2
Within
supramolecular ensembles, there is a possibility to stabi
lize usually lowstable states and intermediates possessing
practically useful properties. Among the most prospective
lightsensitive building blocks, of special value are crown
containing unsaturated compounds
3
capable, on the one
hand, to form complexes at the macrocyclic fragment of
the type host—guest with metal and ammonium cations
and, on the other hand, to exhibit photosensitive proper
ties due to the presence of the C=C bond in the chro
mophore fragment.
One of the most efficient, yet little studied methods
for the selfassembling of crowncontaining unsaturated
compounds is the formation of hydrogen bonds between a
primary ammonium group and a 18crown6 ether frag
ment complementary to it. For instance, earlier we have
shown
4,5
that in the MeCN solution, there are formed
* Dedicated to Academician O. N. Chupakhin on the occasion
of his 75th birthday.
unusually stable bimolecular (logK
1:1
to 9.42) and exotic
enough trimolecular chargetransfer complexes (D—A
and D—A—D, respectively, where D is a donor, A is
an acceptor) between bis(18crown6)stilbene and
N,N´di(ammonioalkyl) derivatives of viologen vinylogs
due to the homoditopic complexation of the NH
3
+
groups
with the crown ether fragments. Despite the close arrange
ment of the ethylene bonds in the complexes D—A, there
is no [2+2] photocycloaddition reaction in them due to
— pyridine residue, — ammonioalkyl substituent,
— benzo18crown6 ether fragment