XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
244
T2: P–29
Spectroscopic IR, Raman, UV-Vis and quantum DFT methods as tools
for recognition of isomeric triazolo[4,5-b]- and [4,5-c]-pyridine forms
Lucyna Dymińska
1
, Iwona Bryndal
1
, Khalil Salem M. Sheweshen
2
,
Jadwiga Lorenc
1
, and Jerzy Hanuza
3
1
Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of
Engineering and Economics, Wrocław University of Economics, Komandorska 118/120, 53-345
Wrocław, Poland, e-mail: iwona.bryndal@ue.wroc.pl
2
Faculty of Agriculture at Azzaytuna University, Azzaytuna, Lybia
3
Divison of Optical Spectroscopy, Institute of Low Temperature and Structure Research, Polish
Academy of Sciences, 50-950 Wrocław, Okólna 2, Poland
The [4,5-b] and [4,5-c] triazolopyridine isomers appear in variety of biologically active
compounds, including antibacterial, antithrombotic, antiinflammatory, antiproliferative and
herbicidal agents. Pharmacological properties of such compounds are of a special importance
because triazolopyridine can inhibit beta-1,6-glucan synthesis and show antifungal activities and
possess chemotherapeutic (antiviral, anti-inflammatory, analgesic, antimicrobial, anti-
hypertensive, antitubular, and anticancer) properties. The importance of these materials and their
broad applications make finding fast and efficacious methods to discriminate compounds
derived from these isomers necessary. In the present work we compare 7-methyl-1H-
[1,2,3]triazolo[4,5-c]pyridinium (7MTPHc) and 6-methyl-1H-[1,2,3]triazolo[4,5-b] pyridine
(6MTPb) which contain the triazolo[4,5-c]- and triazolo[4,5-b]-pyridine skeletons in their
structure. Their IR, Raman, UV-VIS spectra have been measured and analyzed on the basis of
DFT quantum chemical calculations in which the B3LYP/6-311G(2d,2p) approach was applied.
7MTPHc
6MTPb
1800
1600
1400
1200
1000
800
600
400
5
1
5
4
6
0
7
4
8
1
3
2
2
1
2
7
5
6MTPb
7MTPc
A
b
s
o
rb
a
n
c
e
Wavenumber [cm
-1
]
6
9
9
A
1500
1000
500
4
4
0
5
2
1
1
3
2
3
7
7
6
1
2
7
5
7MTPc
6MTPb
Wavenumber [cm
-1
]
R
a
m
a
n
i
n
te
n
s
it
y
6
9
9
B
200
250
300
350
400
2
1
2
2
3
7
3
0
6
3
2
2
2
9
3
7MTPHc
6MTPb
Wavelength [nm]
A
b
s
o
rb
a
n
c
e
2
2
4
C
Fig. 1. The structures and IR (A), Raman (B) and UV-VIS (C) spectra of 7MTPHc and 6MTPb derivatives.
The following conclusions can be drawn from the spectroscopic studies and theoretical
considerations:
(1) IR, Raman and UV-Vis spectra show a characteristic pattern of the bands that can be used as
a diagnostic tool for identification of double ring systems in different triazolopyridine
derivatives containing the [4,5-b] and [4,5-c] isomeric skeletons;
(2) DFT calculations reflect the spectroscopic characteristics of the both studied systems and
their diagnostic differences.
Keywords: triazolopyridine derivatives; IR and Raman spectra; UV-VIS spectra
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
245
T2: P–30
Structural, vibrational and DFT studies of two isomers
of 3(or 5)-nitro-2-phenylpicolines-5(or 3)
Iwona Bryndal
1
, Jadwiga Lorenc
1
, Edyta Kucharska
1
,
Jacek Michalski
1
, and Jerzy Hanuza
2
1
Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of
Engineering and Economy, University of Economics, Komandorska 118/120, 53 - 345 Wrocław,
Poland, e-mail: iwona.bryndal@ue.wroc.pl
2
Division of Optical Spectroscopy, Institute of Low Temperature and Structure Research, Polish
Academy of Sciences, Okólna 2, 50-950 Wrocław, Poland
The picolines are intensively studied due to their wide applications in organic syntheses and
use as bioactive agents in pharmaceuticals [1]. On the other hand, nitropyridines often exhibit
non-linear optical properties and can be used as “bulk unit” in the functional materials [2].
In this contribution, we have synthesized and studied new compounds belong to classes of
amino derivatives of nitropicolines, 5-methyl-3-nitro-2-N-phenylaminopyridine (Ph5M3NP)
(Fig. 1) and 3-methyl-5-nitro-2-N-phenylaminopyridine (Ph3M5NP). The crystal and molecular
structures of the studied compounds have been determined by means of X-ray diffraction and
quantum chemical DFT analysis. The 6-311++G(d,p) basis set with the B3LYP functional has
been used to discuss the optimized structure and vibrational dynamics of the studied compounds.
Their IR (Fig. 2) and Raman spectra have been measured and compared to the calculated
wavenumbers and to those of similar compounds previously reported by us [3–5]. Normal
modes of amine, nitro and methyl groups and pyridine and phenyl rings have been identified
together with the PED values.
3500
3000
1600
1400
1200
1000
800
600
Ph3M5NP
Ph5M3NP
A
b
s
o
rb
a
n
c
e
a
.u
.
Wavenumber / cm-1
Keywords: nitropicoline derivatives; FT-IR and Raman spectroscopy; single-crystal X-ray diffraction
References
[1] N.J. Wheate, S. Walker, G.E. Craig, R. Oun, Dalton Trans. 39 (2010) 8113.
[2] H. Koshima, H. Miyamoto, I. Yagi, K. Uosaki, Cryst. Growth Des. 4 (2004) 807.
[3] I. Bryndal, E. Kucharska, W. Sąsiadek, M. Wandas, T. Lis, J. Lorenc, J. Hanuza, Spectrochim. Acta A
96 (2012) 952.
[4] E. Kucharska, I. Bryndal, J. Hanuza, T. Lis, Spectrochim. Acta A 127 (2014) 303.
[5] E. Kucharska, I. Bryndal, T. Lis, J. Lorenc, J. Hanuza, Vib. Spectrosc. 83 (2016) 70.
Fig. 1. The molecular structure of Ph5M3NP
with atom-numbering scheme. Displacement
ellipsoids are drawn at 50% probability level.
The dotted line indicates intramolecular N-
H•••O hydrogen bond.
Fig. 2. Fig. 2. Experimental IR spectra of
Ph5M3NP (dotted line) and Ph3M5NP (solid
line).
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