Changes induced by solvent polarity in electronic absorption spectra of some nucleic acid constituents

doi:10.1016/j.fluid.2011.08.028

Fluid Phase Equilibria

Volume 312, 25 December 2011, Pages 37-59

https://doi.org/10.1016/j.fluid.2011.08.028 Get rights and content

Abstract

The electronic absorption spectra of some biologically active nucleic acid constituents in various solvents of different polarities and with variable physical properties have been studied at room temperature. These compounds are of two categories (pyrimidines: [barbital; 5,5′-diethyl-barbituric acid], [SBA; 4,6-dihydroxy-2-mercapto-pyrimidin], [NBA; 5-nitro-2,4,6(1H,3H,5H)-pyrimidine trione] and [TU; 2,3-dihydro-2-thioxo-pyrimidin-4(1H)-one]) and (purines: [adenine; 6-amino purine] and [guanine; 2-amino-6-hydroxy purine]). The solvent effects on the wavenumbers of the absorption band maxima (ύ_max) were discussed using the following solvent parameters: refractive index (n), dielectric constant (D) and empirical Kamlet–Taft solvent parameters, π* (dipolarity/polarizability), α (hydrogen bond donating capacity) and β (hydrogen bond accepting ability) using multiple linear regression method (MLR). The solute–solvent interactions were determined on the basis of multilinear solvation energy relationships concept. The data of the studied molecules are affected by both non-specific and specific solute–solvent interactions. The solvatochromic behavior was explained.

Highlights

► Bathochromic shifts of some nucleic acid are related to increase solvent polarity. ► Some solvent parameters affect the behaviour with solute–solvent interactions. ► Non-specific interaction model is applied.

Introduction

Nucleic acid compounds either pyrimidines or purines have much attention due to the widespread range of biological applications in pharmaceutical field. Thiopyrimidine derivatives exhibit antiviral and chemotherapeutic activity [1]. These are physiologically important essential for the biosynthesis of proteins [2], [3]. They possess a very important chemical role in industrial applications where these classes of organic compounds are widely used in recent years as corrosion inhibitors for metals in acid environments [4]. In our laboratory, Masoud et al. [5], [6], [7], [8], [9], [10], [11], [12], [13], [14] published a series of papers to throw light on the chemistry of the biologically active purine and pyrimidines, beside the effect of solvents on their electronic absorption spectra [15], [16], [17], [18]. This can be influenced by non-specific interactions such as ion-dipole, dipole–dipole (Keesom interaction), induced dipole–permanent dipole interactions (Debye interaction) or by specific interaction such as hydrogen bonding with solvents. Thus, solvents play an important role in physical and chemical processes and can determine change in the position, intensity and shape of absorption bands [19], [20]. Solvatochromism is a powerful tool to investigate the physical–chemical properties of molecules [21]. It is well known that the effects of solvents on physical–chemical phenomena and spectroscopic data are better analyzed in terms of a linear combination of solvent properties, including solvent dipolarity/polarizability (π*), hydrogen-bond donation ability [solvent acidity] (α) and hydrogen-bond acceptance ability [solvent basicity] (β).

The aim of the present work is to investigate the solvent influence on the UV–Vis absorption spectra of some pyrimidines and purines and to evaluate the information about intermolecular interactions occurring in solutions. The spectral characteristics of the studied ligands in different solvents at room temperature were analyzed by SPSS programmed. A linear correlation between experimental spectral values (ύ_max) and the solvent parameters: f (n²) and f (D), or the solvatochromic empirical variables (π*, α and β) have been used to discuss the solvatochromic behavior of the analyzed ligands to evaluate their contributions to the solute–solvent interactions.

Section snippets

Compounds

The colour, m.p. (°C) and sources of investigated ligands are given in Table 1, and their chemical structures are presented in the following:

Solvents

Both polar and non-polar solvents in the present work were of spectroscopic grade (HPLC and BDH) reagents and were used without further purification. Their purities were checked from its analytical assay and by recording their electronic spectra. Refractive index (n), dielectric constant (D) and the solvatochromic parameters (π*, α and β) were taken from

Solvent effects on the UV–Vis absorption spectra

The wavenumber in the electronic absorption maxima of the ligands in the selected solvents are given in Table 4, and Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6. The spectra exhibit a series of bands affected by the structure of the organic compounds and the solvents used.

Thiouracil in presence of different solvents where the shift of λ_max based on refractive index (n) or dielectric constant (D) proceeds in an irregular trend. In presence of hydrogen bonding solvents (e.g., H₂O, MeOH, EtOH, i

Conclusions

The electronic absorption spectra of some nucleic acid substituents were recorded in solvents having different physical–chemical properties. A large bathochromic shift (positive solvatochromism) of these compounds was observed upon increasing the solvent polarity. The spectral shifts in the electronic absorption spectra of the studied ligands were quantitatively expressed by means of LSER model. Thus, correlations (MLR analysis) between wavenumber in the maximum of absorption band (ν_max) of

References (40)

M.S. Masoud et al.
Spectrochim. Acta Part A
(2004)
M.S. Masoud et al.
Corros. Sci.
(2010)
M.S. Masoud et al.
Spectrochim. Acta
(2004)
M.S. Masoud et al.
Spectrochim. Acta
(2005)
M.R. Yazdanbakhsh et al.
J. Mol. Liq.
(2009)
D.O. Dorohoi
Spectrochim. Acta Part A
(2010)
A. Airinei et al.
J. Mol. Liq.
(2010)
C. Reichardt
Solvents and Solvent Effects in Organic Chemistry
(2003)
C. Reichardt
Chem. Rev.
(1994)
J.G. Kirkwood
J. Chem. Phys.
(1934)
F.W. Fowler et al.
J. Chem. Soc. (B)
(1971)

V. Stamatovska et al.

Bull. Chem. Technol. Macedon.

(2006)

M.J. Kamlet et al.

J. Chem. Soc. Perkin Trans.

(1979)

V.N. Krishnamurthy et al.

Brit. J. Pharmacol. Chemother.

(1967)

M.S. Masoud et al.

Pol. J. Chem.

(1991)

M.S. Masoud et al.

J. Therm. Anal.

(1992)

M.S. Masoud et al.

Spectrosc. Lett.

(1994)

M.S. Masoud et al.

Z. Phys. Chem. Bd.

(1999)

M.S. Masoud et al.

Z. Phys. Chem.

(2001)

M.S. Masoud et al.

Indian J. Chem.

(2002)

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¹: Abstracted from her Ph.D.thesis.

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Changes induced by solvent polarity in electronic absorption spectra of some nucleic acid constituents

Abstract

Highlights

Introduction

Section snippets

Compounds

Solvents

Solvent effects on the UV–Vis absorption spectra

Conclusions

Spectrochim. Acta Part A

Corros. Sci.

Spectrochim. Acta

Spectrochim. Acta

J. Mol. Liq.

Spectrochim. Acta Part A

J. Mol. Liq.

Chem. Rev.

J. Chem. Phys.

J. Chem. Soc. (B)

Bull. Chem. Technol. Macedon.

J. Chem. Soc. Perkin Trans.

Brit. J. Pharmacol. Chemother.

Pol. J. Chem.

J. Therm. Anal.

Spectrosc. Lett.

Z. Phys. Chem. Bd.

Z. Phys. Chem.

Indian J. Chem.