X-ray diffraction analysis and luminescence spectral study of crystal solvates of N-(N′-tosylanthranoyl)anthranilic acid with acetic acid and dimethylformamide

Article abstract of DOI:10.1023/A:1011389601879

Two crystal modifications of N-(N′-tosylanthranoyl)anthranilic acid were studied by X-ray diffraction analysis and luminescence spectroscopy. One crystal modification is a crystal solvate with acetic acid and is characterized by green fluorescence. Another modification is a crystal solvate with DMF and exhibits blue fluorescence. The modifications differ in the melting point.

Full text of DOI:10.1023/A:1011389601879

728
Russian Chemical Bulletin, International Edition, Vol. 50, No. 4, pp. 728—730, April, 2001
Brief Communications
X-ray diffraction analysis and luminescence spectral study
of crystal solvates of N-(N´-tosylanthranoyl)anthranilic acid
with acetic acid and dimethylformamide
A. N. Utenyshev,a« B. M. Bolotin,b and R. U. Safinab
aInstitute of Problems of Chemical Physics, Russian Academy of Sciences,
142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (096) 515 3588. E-mail: atom@icp.ac.ru
bState Scientific Research Institute of Chemical Reagents and Pure Materials,
3 Bogorodskii Val, 107076 Moscow, Russian Federation.
Fax: +7 (095) 963 7450. E-mail: olbo@ntl.ru
Two crystal modifications of N-(N´-tosylanthranoyl)anthranilic acid were studied by X-ray
diffraction analysis and luminescence spectroscopy. One crystal modification is a crystal
solvate with acetic acid and is characterized by green fluorescence. Another modification is a
crystal solvate with DMF and exhibits blue fluorescence. The modifications differ in the
melting point.
Key words: luminescence, crystal structure, fluorescence, derivatives of anthranilic acid,
hydrogen bond.
When performing recrystallization of N-(N´-tosyl-
Results and Discussion
anthranoyl)anthranilic acid (1) from acetic acid and
DMF, we found that acid 1 formed crystals exhibiting
different fluorescence, viz., green (1a) and blue (1b).
Crystal modifications 1a and 1b differ also in the melt-
ing point (206 and 197 °C, respectively). With the aim of
establishing the structures of both crystal modifications
and revealing the reasons for the difference in their
luminescence properties, we studied these single crystals
by X-ray diffraction analysis.
According to the X-ray diffraction data, molecule 1a
(Fig. 1) is nonplanar. Benzene rings À and  are rotated
about the C(1)—N(2) bond by 18.1°. Benzene rings Â
and C are rotated about the N(1)—S bond by 106.7°. In
crystal solvate 1b (Fig. 2), the central fragment of
molecule 1 is virtually planar. Benzene rings À and  are
rotated about the C(1)—N(2) bond by 4.6°, and benzene
rings  and C are rotated about the N(1)—S bond by
9.8°. The carboxyl group of molecule 1a is involved in
two intermolecular hydrogen bonds with the molecule of
acetic acid: the O(5)...O(7) and H(23)...O(7) inter-
atomic distances are 2.694(3) and 1.88(2) Å, respectively
(the H(23)—O(5) bond length is 0.82(2) Å), the
O(5)—H(23)—O(7) angle is 173.5(2)°, the O(4)...O(6)
and H(24)...O(4) distances are 2.728(3) and 2.00(2) Å,
respectively (the H(24)—O(6) bond length is 0.73(2) Å),
H
HOOC
N
HN SO2
Me
O
1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 699—701, April, 2001.
1066-5285/01/5004-728 $25.00 © 2001 Plenum Publishing Corporation

X-ray diffraction analysis of crystal solvates
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 4, April, 2001
729
one, and yet stronger, intermolecular hydrogen bond
with the O atom of the carbonyl group of DMF: the
O(5)...O(6) and H(51)...O(6) interatomic distances are
2.576(3) and 1.45(2) Å, respectively (the H(51)—O(5)
bond length is 1.15(2) Å), the O(5)—H(51)—O(6) angle
is 165.5(2)°. The O(4) atom of the carbonyl group in
crystal 1b is not involved in intermolecular hydrogen
bonding (the C(21)—O(4) bond length is 1.218(3) Å),
whereas this atom in crystal 1a participates in hydrogen
bonding (the C(21)—O(4) bond length is 1.225(2) Å).
The involvement of the O(6) atom of the carbonyl bond
of the DMF molecule in intermolecular hydrogen bond-
ing leads to substantial elongation of the C(22)—O(6)
bond (1.237(3) Å). The DMF molecule in crystal 1b is
virtually perpendicular to the central fragment of mol-
ecule 1. The angle between the plane of the DMF
molecule and the plane passing through the atoms of the
central fragment of molecule 1 is 107.8(2)°. The O(1)
and O(4) atoms of the carbonyl groups in crystals 1a and
1b form intramolecular hydrogen bonds with the amide
H(1) and H(2) atoms, respectively. The parameters of
the above-listed intramolecular hydrogen bonds are given
in Table 1. The O(1)...N(1) distance in 1a is increased
due to rotation of benzene rings À and  about the
C(1)—N(1) bond.
O(7)
O(5)
C(10)
C(9)
C(11)
C(12)
C(22)
C(23)
C(21)
C(8)
O(4)
C(13)
O(6)
N(2)
C(1)
O(1)
C(2)
C(7)
H(1)
N(1)
O(2)
C(6)
C(5)
C(3)
C(4)
S
C(15)
O(3)
C(14)
C(20)
C(19)
C(16)
C(17)
C(18)
Fig. 1. Overall view of crystal solvate 1a.
Apparently, a higher degree of nonplanarity of mol-
ecule 1a (green fluorescence), which is stabilized in the
crystal (Fig. 3) by intermolecular hydrogen bonds be-
tween the COOH groups of molecules 1 and CH3COOH,
and the resulting weakening of N—H...O intramolecular
hydrogen bonds leads to the fact that the excited mol-
ecule (after absorption of an exciting photon) adopts a
coplanar form favorable for more efficient π-conjugation.
This, in turn, leads to a decrease in the energy of the
lower excitation level and, as a consequence, to a de-
crease in the energy of the emitted luminescence photon.
After emission of the photon, the molecule reverts to the
ground state and then changes once again to regain its
initial geometrical configuration. These changes, which
occur in nonplanar molecule 1a and which are absent in
molecule 1b, result not only in the bathochromic shift of
the fluorescence band of the "green" form by 22 nm
compared to that of the "blue" form (the fluorescence
maxima are observed at 504 and 482 nm, respectively)
(Fig. 4), but also in the hypsochromic shift of the long-
wavelength excitation band of the molecules in crystal 1a.
C(23)
N(3)
C(22)
O(6)
C(24)
O(5)
C(15)
C(10)
C(9)
O(4)
H(2)
C(7)
C(2)
C(11)
C(12)
C(8)
C(1)
O(1)
C(13)
C(6)
C(5)
C(4)
C(3)
N(1)
S
O(2)
O(3)
C(14)
C(15)
Table 1. Parameters of hydrogen bonds in crystals 1a and 1b
C(20)
Parameter
1a
1b
C(19)
C(17)
C(16)
C(18)
Interatomic distance
O(1)...N(1)
d/Å
2.611(3)
1.88(2)
2.641(3)
1.82(2)
2.532(3)
1.80(2)
2.634(3)
1.90(2)
O(1)...H(1)
O(4)...N(2)
O(4)...H(2)
Fig. 2. Overall view of crystal solvate 1b.
Bond angle
ω/deg
O(1)—H(1)—N(1)
O(4)—H(2)—N(2)
142.8(2)
146.0(2)
144.1(2)
147.2(2)
and the O(4)—H(24)—O(6) angle is 171.0(2)°. The carb-
oxyl group in 1b, unlike that in 1a, is involved only in

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Russ.Chem.Bull., Int.Ed., Vol. 50, No. 4, April, 2001
Utenyshev et al.
space group P21/c, a = 8.573(2), b = 16.368(3), c = 16.195(3) Å,
β = 92.48(3)°, V = 2270.4(8) Å3, dc = 1.345 g cm–3, Z = 4; for
1b: C21H18N2O5S•(CH3)2NCOH, M = 483.45, monoclinic
system, space group P21/n, a = 23.290(5), b = 11.050(2),
c = 9.458(2) Å, β = 101.30(3)°, V = 2386.9(8) Å3, dc
=
1.345 g cm–3, Z = 4. The intensities of 4843 (1a) and 4974 (1b)
independent reflections with I > 2σ(I ) were measured on an
automated four-circle KM-4 diffractometer (Mo-Kα radiation).
Both structures were solved by the direct method (SHELX-86)1
and refined anisotropically by the full-matrix least-squares
method (SHELXL-93).2 The H atoms in the structure of 1a
were located from the Fourier synthesis and only their posi-
tional parameters were refined. In the structure of 1b, the H
atoms of the methyl groups were placed in geometrically calcu-
lated positions and all other atoms were revealed from the
Fourier synthesis. The final values of the R factor were 0.046
(1a) and 0.047 (1b). The atomic coordinates and interatomic
distances were deposited with the Cambridge Structural
Database.
The fluorescence spectra were recorded on an LS-5
(Perkin—Elmer) spectrofluorimeter with 2.5-nm slits of both
monochromators (a flash xenon lamp as the excitation source
(∼100 Hz), the scan rate was 60 nm min–1, the response time
was 1 s, the amplification was 1, the 3% attenuator). The
excitation and fluorescence spectra were corrected taking into
account the sensitivity of the photoelectric multiplier to differ-
ent wavelengths. The excitation spectra were measured at the
fluorescence maximum. The fluorescence spectra were excited
with light with the wavelength 365 nm.
Fig. 3. Fragment of the stacked packing of molecules 1 in
crystal 1a.
N-(N´-Tosylanthranoyl)anthranilic acid (1). Water (2 mL)
was added to a solution of 2-(2-tosylaminophenyl)-4H-3,1-
benzooxazin-4-one (5 g) in pyridine (70 mL). The reaction
mixture was refluxed for 1 h, cooled, poured into water
(300 mL), and acidified with HCl to ðH 6. The precipitate that
formed was filtered off, thoroughly washed with water, and
dried at ∼20 °C. Crystals of 1a (m.p. 206 °C) were prepared
by crystallization from glacial acetic acid. Crystals of 1b
(m.p. 196 °C) were obtained by crystallization from aque-
ous DMF.
I/I0
357
482
90
2´
2
504
344
1
70
50
30
10
1´
References
1. G. M. Sheldrick, SHELX-86; Program for Crystal Structure
Determination, University of Cambridge (England), Cam-
bridge, 1986.
2. G. M. Sheldrick, SHELX-93; Program for Crystal Structure
Determination, University of Cambridge (England), Cam-
bridge, 1993.
300
400
500
600
λ/nm
Fig. 4. Excitation (1, 2) and fluorescence (1´, 2´) spectra of
crystalline powders of 1a (1, 1´) and 1b (2, 2´).
Experimental
Principal
crystallographic
data
for
1a:
Received October 20, 1999;
in revised form October 11, 2000
C21H18N2O5S•CH3COOH, M = 470.43, monoclinic system,