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Papers by Manju Kumari Saroj

Research paper thumbnail of Linear solvation energy relationship of 3-(1′H-indol-3′-yl)-1-phenylprop-2-en-1-ones using Kamlet-Taft and Catalan solvent parameters

Steady-state absorption and fluorescence techniques have been used to study the photophysical pro... more Steady-state absorption and fluorescence techniques have been used to study the photophysical properties of the fluorescent 3-(1′H-Indol-3′-yl)-1-phenylprop-2-en-1-one (IC) derivatives via Kamlet-Taft and Catalan treatments. In a refined work of the non-specific interactions of these derivatives in various solvents, a complete set of Kamlet-Taft and Catalan scales has been employed, which enables to separate the polarizability, hydrogen-bond donor and hydrogen-bond acceptor abilities of these derivatives. The Kamlet-Taft and Catalan treatments of these derivatives in the ground state suggest that the IC derivatives can well behave both as hydrogen bond acceptors and donors due to the simultaneous presence of carbonyl and NH groups, whereas, in excited state only the hydrogen bond accepting ability counts.

Research paper thumbnail of Study of prototropic reactions of indole chalcone derivatives in ground and excited states using absorption and fluorescence spectroscopy

Journal of Molecular Liquids, 2019

Research paper thumbnail of Investigation of indole chalcones encapsulation in β-cyclodextrin: determination of stoichiometry, binding constants and thermodynamic parameters

Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2018

The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives wit... more The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives with β-cyclodextrin (β-CD), which involves absorption and steady state fluorescence spectroscopies. The formation of inclusion complexes is validated by increase in their absorbance and fluorescence intensity as well as the blue shift with increase in the concentration of β-CD in the aqueous solution. The stoichiometries and binding constants (K in) of these complexes have been investigated by monitoring their absorbance and fluorescence spectral profiles. The data are analyzed by Benesi-Hildebrand plots as well as Job's method, which indicate 1:1 stoichiometry of IC:β-CD complexes. Fluorescence measurements are also used to investigate the effect of temperature on the stability of inclusion complexes. Stability of IC:β-CD complexes is significantly affected with variation in substituents on the phenyl ring and temperature. It is observed that the stability of the inclusion complex decreases with increase in temperature; K in(293 K) > K in(298 K) > K in(308 K) > K in(318 K). All the experimental results and the geometrical data obtained using PM3 semiempirical method illustrate the partial inclusion of IC derivatives from the phenyl ring side in β-CD cavity. The binding process of IC derivatives with β-CD is found to be exothermic in nature and seems to be controlled by electrostatic and hydrophobic forces. The binding free energies calculated using semiemprical PM3 method for IC:β-CD complexes are found to be in the order: I < OH-I < Me-I < OMe-I < NH 2-I, which largely supports the findings based on the experimental binding constants.

Research paper thumbnail of Photophysical study of some 3-benzoylmethyleneindol-2-ones and estimation of ground and excited states dipole moments from solvatochromic methods using solvent polarity parameters

Journal of Molecular Structure, 2012

Abstract 3-Benzoylmethyleneindol-2-ones, isatin based chalcones containing donor and acceptor moi... more Abstract 3-Benzoylmethyleneindol-2-ones, isatin based chalcones containing donor and acceptor moieties that exhibit excited-state intramolecular charge transfer, have been studied in different solvents by absorption and emission spectroscopy. The excited state behavior of these compounds is strongly dependent on the nature of substituents and the environment. These compounds show multiple emissions arising from a locally excited state and the two states due to intramolecular processes viz. intramolecular charge transfer (ICT) and excited state intramolecular proton transfer (ESIPT). Excited-state dipole moments have been calculated using Stoke-shifts of LE and ICT states using solvatochromic methods. The higher values of dipole moments obtained lead to support the formation of ICT state as one of the prominent species in the excited states of all 3-benzoylmethyleneindol-2-ones. The correlation of the solvatochromic Stokes-shifts with the microscopic solvent polarity parameter ( E T N ) was found to be superior to that obtained using bulk solvent polarity functions. The absorption and florescence spectral characteristics have been also investigated as a function of acidity and basicity (Ho/pH) in aqueous phase.

Research paper thumbnail of Structure–activity relationship of dihydroxy-4-methylcoumarins as powerful antioxidants: Correlation between experimental & theoretical data and synergistic effect

Research paper thumbnail of Chapter 8. Differential thermal analysis

De Gruyter eBooks, Jun 5, 2023

Research paper thumbnail of Photophysical behavior of some thymol based schiff bases using absorption and fluorescence spectroscopy

Journal of Luminescence, 2018

The absorption and fluorescence spectra of some biologically active thymol based Schiff bases hav... more The absorption and fluorescence spectra of some biologically active thymol based Schiff bases have been studied at room temperature in a series of solvents of varying polarity. The solvent effect on the spectral properties of Schiff bases has been analyzed using Reichardt and Kawski equations and Kamlet-Taft and Catálan multi-parametric solvent polarity scales. The substituents and the solvents strongly influence the excited state behavior of these molecules owing to different electronic arrangements. The excited state dipole moments( e / g and ) of these molecules have been calculated using solvatochromic shift methods based on bulk solvent polarity functions f (,n) and  (,n) and microscopic solvent polarity parameter N T E , respectively. The increase in excited state dipole moments ( e) indicates a more polar excited state and intramolecular charge transfer (ICT) characteristics of these molecules. The molecular orbitals (HOMO-1, HOMO, LUMO and LUMO+1) and molecular electrostatic potential (MEP) surfaces have been generated from their optimized geometries using semi-empirical (PM3) calculations to account for electronic excitations and changes in the overall charge distribution of Schiff bases. The Taft and Catalán multi-parametric equations used in the interpretation of the specific solute-solvent interactions reveal that the most important contribution to the solute-solvent interaction in the excited state comes from the hydrogen-bond acceptor capacity of the solvent.

Research paper thumbnail of Solvent Effect Profiles of Absorbance and Fluorescence Spectra of Some Indole Based Chalcones

Journal of Fluorescence, 2011

The photophysical properties of a series of 3-(1&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;... more The photophysical properties of a series of 3-(1&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;H-Indol-3&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-yl)-1-phenylprop-2-en-1-one and its derivatives (indole chalcones) were studied in different solvents. Solvent effects on the absorption and fluorescence spectra were quantified using Reichardt&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s and bulk solvent polarity parameters and were complemented by the results of the Kamlet-Taft treatment. The observed excited state dipole moment was found to be larger than the ground state dipole moment of these chalcones. The correlation of the solvatochromic Stokes-shifts with the microscopic solvent polarity parameter (E(T)(N)) was found to be superior to that obtained using bulk solvent polarity functions.

Research paper thumbnail of An experimental and theoretical investigation of inclusion complexes of Indole Chalcones in cyclodextrin

Chemical Sciences Journal, 2018

B iofuel cells, which generate electric power from biomaterials such as glucose, alcohol, organic... more B iofuel cells, which generate electric power from biomaterials such as glucose, alcohol, organic acids, are interested as a potential candidate for sustainable energy sources. The key material for biofuel cells is catalyst, which enhances chemical reaction and conversion efficiency to electric power. However, expensive rare metals like Pt are commonly used for the catalyst. We have been studying biofuel cells to explore the possibility to replace rare metals with functional materials. It was found that conducting polymers exhibited excellent performance as the anode catalyst. In this talk, fabrication of biofuel cells, measurement and characterization of the electrical output using conducting polymer, poly (3,4-ethylenedioxythiophene) Polystyrene Sulfonate (PEDOT*PSS) as the anode catalyst are presented. The biofuels were ascorbic acid (AsA; known as vitamin C), citric acid (CitA), and lemon juice. The output powers based on these biofuels were compared. The cells consisted of biofuel/current collector/PEDOT*PSS /Nafion® (N117)/Pt-B (black) cathode catalyst/current collector/air. For the current collector a low resistance CuNi-coated polymer cloth was used. The cell was a direct and passive type. Figure shows cell performances of electromotive force (E 0), maximum power (P max) and cell voltage (E max) at the power maximum. The highest performance was obtained in the lemon juice cell having the P max about 4 mW/cm2 using PEDOT*PSS anode catalyst. Taking the fact that lemon juice contains approximately 0.03 M AsA and 0.3 M CitA, the Pmax of lemon juice cell is consistent with the sum of them. It is also noted that the cell performances of PEDOT*PSS was better than that of Pt-B for anode catalysts and 0.5 M AsA. The mechanism of high power CuNi/PEDOT*PSS anode cell will be discussed.

Research paper thumbnail of Linear solvation energy relationship of 3-(1′H-indol-3′-yl)-1-phenylprop-2-en-1-ones using Kamlet-Taft and Catalan solvent parameters

Steady-state absorption and fluorescence techniques have been used to study the photophysical pro... more Steady-state absorption and fluorescence techniques have been used to study the photophysical properties of the fluorescent 3-(1′H-Indol-3′-yl)-1-phenylprop-2-en-1-one (IC) derivatives via Kamlet-Taft and Catalan treatments. In a refined work of the non-specific interactions of these derivatives in various solvents, a complete set of Kamlet-Taft and Catalan scales has been employed, which enables to separate the polarizability, hydrogen-bond donor and hydrogen-bond acceptor abilities of these derivatives. The Kamlet-Taft and Catalan treatments of these derivatives in the ground state suggest that the IC derivatives can well behave both as hydrogen bond acceptors and donors due to the simultaneous presence of carbonyl and NH groups, whereas, in excited state only the hydrogen bond accepting ability counts.

Research paper thumbnail of Study of prototropic reactions of indole chalcone derivatives in ground and excited states using absorption and fluorescence spectroscopy

Journal of Molecular Liquids, 2019

Research paper thumbnail of Investigation of indole chalcones encapsulation in β-cyclodextrin: determination of stoichiometry, binding constants and thermodynamic parameters

Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2018

The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives wit... more The study focuses on the formation of inclusion complexes of indole chalcone (IC) derivatives with β-cyclodextrin (β-CD), which involves absorption and steady state fluorescence spectroscopies. The formation of inclusion complexes is validated by increase in their absorbance and fluorescence intensity as well as the blue shift with increase in the concentration of β-CD in the aqueous solution. The stoichiometries and binding constants (K in) of these complexes have been investigated by monitoring their absorbance and fluorescence spectral profiles. The data are analyzed by Benesi-Hildebrand plots as well as Job's method, which indicate 1:1 stoichiometry of IC:β-CD complexes. Fluorescence measurements are also used to investigate the effect of temperature on the stability of inclusion complexes. Stability of IC:β-CD complexes is significantly affected with variation in substituents on the phenyl ring and temperature. It is observed that the stability of the inclusion complex decreases with increase in temperature; K in(293 K) > K in(298 K) > K in(308 K) > K in(318 K). All the experimental results and the geometrical data obtained using PM3 semiempirical method illustrate the partial inclusion of IC derivatives from the phenyl ring side in β-CD cavity. The binding process of IC derivatives with β-CD is found to be exothermic in nature and seems to be controlled by electrostatic and hydrophobic forces. The binding free energies calculated using semiemprical PM3 method for IC:β-CD complexes are found to be in the order: I < OH-I < Me-I < OMe-I < NH 2-I, which largely supports the findings based on the experimental binding constants.

Research paper thumbnail of Photophysical study of some 3-benzoylmethyleneindol-2-ones and estimation of ground and excited states dipole moments from solvatochromic methods using solvent polarity parameters

Journal of Molecular Structure, 2012

Abstract 3-Benzoylmethyleneindol-2-ones, isatin based chalcones containing donor and acceptor moi... more Abstract 3-Benzoylmethyleneindol-2-ones, isatin based chalcones containing donor and acceptor moieties that exhibit excited-state intramolecular charge transfer, have been studied in different solvents by absorption and emission spectroscopy. The excited state behavior of these compounds is strongly dependent on the nature of substituents and the environment. These compounds show multiple emissions arising from a locally excited state and the two states due to intramolecular processes viz. intramolecular charge transfer (ICT) and excited state intramolecular proton transfer (ESIPT). Excited-state dipole moments have been calculated using Stoke-shifts of LE and ICT states using solvatochromic methods. The higher values of dipole moments obtained lead to support the formation of ICT state as one of the prominent species in the excited states of all 3-benzoylmethyleneindol-2-ones. The correlation of the solvatochromic Stokes-shifts with the microscopic solvent polarity parameter ( E T N ) was found to be superior to that obtained using bulk solvent polarity functions. The absorption and florescence spectral characteristics have been also investigated as a function of acidity and basicity (Ho/pH) in aqueous phase.

Research paper thumbnail of Structure–activity relationship of dihydroxy-4-methylcoumarins as powerful antioxidants: Correlation between experimental & theoretical data and synergistic effect

Research paper thumbnail of Chapter 8. Differential thermal analysis

De Gruyter eBooks, Jun 5, 2023

Research paper thumbnail of Photophysical behavior of some thymol based schiff bases using absorption and fluorescence spectroscopy

Journal of Luminescence, 2018

The absorption and fluorescence spectra of some biologically active thymol based Schiff bases hav... more The absorption and fluorescence spectra of some biologically active thymol based Schiff bases have been studied at room temperature in a series of solvents of varying polarity. The solvent effect on the spectral properties of Schiff bases has been analyzed using Reichardt and Kawski equations and Kamlet-Taft and Catálan multi-parametric solvent polarity scales. The substituents and the solvents strongly influence the excited state behavior of these molecules owing to different electronic arrangements. The excited state dipole moments( e / g and ) of these molecules have been calculated using solvatochromic shift methods based on bulk solvent polarity functions f (,n) and  (,n) and microscopic solvent polarity parameter N T E , respectively. The increase in excited state dipole moments ( e) indicates a more polar excited state and intramolecular charge transfer (ICT) characteristics of these molecules. The molecular orbitals (HOMO-1, HOMO, LUMO and LUMO+1) and molecular electrostatic potential (MEP) surfaces have been generated from their optimized geometries using semi-empirical (PM3) calculations to account for electronic excitations and changes in the overall charge distribution of Schiff bases. The Taft and Catalán multi-parametric equations used in the interpretation of the specific solute-solvent interactions reveal that the most important contribution to the solute-solvent interaction in the excited state comes from the hydrogen-bond acceptor capacity of the solvent.

Research paper thumbnail of Solvent Effect Profiles of Absorbance and Fluorescence Spectra of Some Indole Based Chalcones

Journal of Fluorescence, 2011

The photophysical properties of a series of 3-(1&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;... more The photophysical properties of a series of 3-(1&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;H-Indol-3&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-yl)-1-phenylprop-2-en-1-one and its derivatives (indole chalcones) were studied in different solvents. Solvent effects on the absorption and fluorescence spectra were quantified using Reichardt&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s and bulk solvent polarity parameters and were complemented by the results of the Kamlet-Taft treatment. The observed excited state dipole moment was found to be larger than the ground state dipole moment of these chalcones. The correlation of the solvatochromic Stokes-shifts with the microscopic solvent polarity parameter (E(T)(N)) was found to be superior to that obtained using bulk solvent polarity functions.

Research paper thumbnail of An experimental and theoretical investigation of inclusion complexes of Indole Chalcones in cyclodextrin

Chemical Sciences Journal, 2018

B iofuel cells, which generate electric power from biomaterials such as glucose, alcohol, organic... more B iofuel cells, which generate electric power from biomaterials such as glucose, alcohol, organic acids, are interested as a potential candidate for sustainable energy sources. The key material for biofuel cells is catalyst, which enhances chemical reaction and conversion efficiency to electric power. However, expensive rare metals like Pt are commonly used for the catalyst. We have been studying biofuel cells to explore the possibility to replace rare metals with functional materials. It was found that conducting polymers exhibited excellent performance as the anode catalyst. In this talk, fabrication of biofuel cells, measurement and characterization of the electrical output using conducting polymer, poly (3,4-ethylenedioxythiophene) Polystyrene Sulfonate (PEDOT*PSS) as the anode catalyst are presented. The biofuels were ascorbic acid (AsA; known as vitamin C), citric acid (CitA), and lemon juice. The output powers based on these biofuels were compared. The cells consisted of biofuel/current collector/PEDOT*PSS /Nafion® (N117)/Pt-B (black) cathode catalyst/current collector/air. For the current collector a low resistance CuNi-coated polymer cloth was used. The cell was a direct and passive type. Figure shows cell performances of electromotive force (E 0), maximum power (P max) and cell voltage (E max) at the power maximum. The highest performance was obtained in the lemon juice cell having the P max about 4 mW/cm2 using PEDOT*PSS anode catalyst. Taking the fact that lemon juice contains approximately 0.03 M AsA and 0.3 M CitA, the Pmax of lemon juice cell is consistent with the sum of them. It is also noted that the cell performances of PEDOT*PSS was better than that of Pt-B for anode catalysts and 0.5 M AsA. The mechanism of high power CuNi/PEDOT*PSS anode cell will be discussed.