Russian Chemical Bulletin, International Edition, Vol. 66, No. 11, pp. 2122—2125, November, 2017
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2122—2125, November, 2017.
10665285/17/66112122 © 2017 Springer Science+Business Media, Inc.
New indoline spiropyrans containing azomethine fragment
O. A. Komissarova,
B. S. Lukyanov,
M. B. Lukyanova,
I. V. Ozhogin,
E. L. Mukhanov,
M. S. Korobov,
I. A. Rostovtseva,
and V. I. Minkin
Institute of Physical and Organic Chemistry at Southern Federal University,
194/2 prosp. Stachki, 344090 RostovonDon, Russian Federation.
Fax: +7 (863) 243 4177. Email: email@example.com
Don State Technical University,
1 pl. Gagarin, 344000 RostovonDon, Russian Federation
The new spiropyran systems with an azomethine bridge were synthesized from a spiro
pyran containing aminogroup at 6
position of the benzopyran fragment and substituted
aromatic aldehydes. The chemical structure of compounds is confirmed by elemental analy
sis data, NMR (
C) and IR spectroscopy. Photochemical studies revealed the pres
ence of photochromic properties at room temperature for one of the obtained spiropyrans.
Key words: spiropyran, photochromism, molecular switch, azomethine, Schiff base.
Spiropyrans and their derivatives are one of the most
interesting classes of organic photochromes.
photochromic properties are based on a photoinduced
cleavage of the C
—O bond with following isomeriza
tion leading to the "open" merocyanine form.
properties make it possible to use spiropyrans in many
cutting edge areas: molecular electronics and photonics,
chemosensorics, biomedicine, etc.
An increase in the conjugation system during photo
initiated opening of the pyran fragment may lead to
a significant bathochromic shift of the maximum in an
electronic absorption spectrum, making such materials
promising for the creation of information recording sys
tems based on nearIR lasers.
Compounds having the photochromic spiropyran
bound by a common conjugation system with a spatially
enlarged substituent are characterized by the fact that an
electronical interaction is possible between the fragments
of their molecules, resulting in the ability of a substituent
to have a significant effect on the spectral and photo
kinetic characteristics of such structures.
This work is aimed at the synthesis and study of new
spiropyrane systems based on spiropyran 1, containing
aminogroup at 6
position of the benzopyran fragment,
and various aromatic aldehydes. In the obtained spiro
compounds the spatially enlarged substituent is bound to
2Hchromene fragment of spiropyran molecule via a con
acceptor C=N bond, which distinguishes these
systems from previously studied ones.
Results and Discussion
The desired spiropyrans were obtained by condensa
tion between equimolar amounts of spiropyran 1 and ap
propriate aromatic aldehydes 2 in the presence of triethy
lamine in boiling benzene (Scheme 1).
Compound 2, 3 R
b H OMe H
The chemical structures of spiropyrans 3 were con
firmed by elemental analysis data, NMR and IR spec
H NMR spectra of the spiropyrans show signals from
all the protoncontaining groups, while values of the
chemical shifts and Jcoupling constants confirm com
pletely the structure of the obtained compounds.
The signals of the gemdimethyl groups at position 3
appear as two threeproton singlet signals at 1.17 and
1.31 ppm, the singlet signals of methyl protons at posi