XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
335
T9: P–9
Chrysin. Spectroscopic (UV-VIS and IR) characterization
supported by DFT calculations and comparative study of calculated
and experimental pK
a
values in aqueous solution
Anna Kuźniar
1
, Urszula Maciołek
1
, Tadeusz Pietryga
2
, Janusz Pusz
1
,
Małgorzata Kosińska
1
, and Lidia Zapała
1
1
Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, Rzeszow University of
Technology, Al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland, e-mail: akuzniar@prz.edu.pl
2
Department of Physical Chemistry, Faculty of Chemistry, Rzeszow University of Technology, Al.
Powstańców Warszawy 6, 35-959 Rzeszów
Computional calculations are used in theoretical investigations of the physical and chemical
properties of flavonoids, to disclose of relationship between the structure and their properties, to
predict the possible complexation sites or interpretation of changes after metal ions coordination [1].
In this work, the theoretical and experimental results on the studies of spectral properties of chrysin
were shown. Moreover the potentiometric and the Yasuda-Shedlovsky extrapolation methods were
used to determine the protonation (dissociation) constants for chrysin in the water and selected set of
quantum chemistry methods were applicated to calculate two pK
a
s of chrysin in water. In addition,
the methods were checked regarding their giving similar results to experimental and literature data.
Chrysin (5,7-dihydoxyflavone, Fig. 1) is one of the less known flavonoids. It naturally occurs in
passion flowers Passiflora caerulea, Passiflora incarnata and Oroxylum indicum. It is also found in
chamomile, in the mushroom Pleurotus ostreatus and in honeycomb. Among biological properties,
antiallergic, antioxidant, anti-inflammatory and anticancer acitivity is postulated for chrysin [2].
O
O
O
H
OH
1
2
3
4
5
6
7
8
1'
2'
3'
6'
5'
4'
Fig. 1. The molecular structure of chrysin.
Additionally, due to presence of functional groups at 4 i 5 positions, chrysin exhibit complexing
properties. Therefore, well characterized spectra properties are necessary in comparative analysis with
resulting complex.
The molecular geometry and vibrational wavenumbers of chrysin have been calculated in ground
state by using DFT method and various functionals (B3LYP, B3PW91, B97D, pbe1pbe, X3LYP,
M062X). Electronic absorption spectra of the title compound have been predicted with use Time
Dependent Density Functional Theory (TD-DFT) method and several different functional including
CAM-B3LYP, BP86, B3LYP, B3P86, M06-2X, B3PW91, B97D3. All calculations were performed
with Gaussian09 software.
Simultaneously with computational calculation, the FT-IR and UV-Vis spectra of the investigated
compound dissolved in different solvents (ethanol, methanol, water and DMSO) were recorded.
The obtained theoretical infrared and absorption spectra were tested in range of the best fitting to
the experimental data and used in analysis of spectral properties of chrysin.
Keywords: Chrysin; DFT methods
References
[1] S.A. Payán-Gómez, N. Flores-Holguín, A. Pérez-Hernández, M. Piñón-Miramontes, D. Glossman-
Mitnik, Chem. Cent. J. 4(12) (2010) 1.
[2] E. Pichichero, R. Cicconi, M. Mattei, A. Canini, Int. J. Oncol. 38 (2011) 473.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
336
T9: P–10
Structure of octaphenyl and octavinyl octasilsesquioxane
Witold Jastrzębski
1
, Bartosz Handke
1
1
AGH University of Science and Technology, Faculty of Material Science and Ceramics, Al.
Mickiewicza 30, 30-059 Kraków, Poland, e-mail: witjas@agh.edu.pl
The cage silsesquioxanes are well-known organic-inorganic hybrid materials. Yet, the
crystalline structure for numerous compounds remains unknown or questionable. Even though
cage silsesquioxane tend to form well define molecular crystals, rarely the crystallites size is
enough for single crystalline structural studies. This work deals with an unknown so far crystal
structure of Vinyl octasilsesquioxane (T8) and Phenyl-T8 [1]. Models of both structures were
optimized at ab initio level and compared with FTIR spectroscopy measurements. For long-
range order investigations, powder X-ray diffraction patterns were fitted with structural model
solved using reverse Monte-Carlo direct space method, similarly as for previously studied
compound [2].
Fig. 1. T8-vinyl crystal model.
References
[1] P.R. Chinnam, M.R. Gau, J. Schwab, M.J. Zdilla, S.L. Wunder, Acta Cryst. C70 (2014) 971.
[2] B. Handke, W. Jastrzębski, M. Kwaśny, Ł. Klita, J. Mol. Struct. 1028 (2012) 68.
Dostları ilə paylaş: |