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Research paper thumbnail of Two-dimensional IR spectroscopy reveals a hidden Fermi resonance band in the azido stretch spectrum of β-azidoalanine

Physical Chemistry Chemical Physics

The 2D-IR spectrum of Ala-N3 shows cross-peak, but cannot be identified clearly. The 1D slice spe... more The 2D-IR spectrum of Ala-N3 shows cross-peak, but cannot be identified clearly. The 1D slice spectra obtained from 2D-IR spectrum reveals the presence of hidden Fermi resonance peak.

Research paper thumbnail of Thioether-functionalized Covalent Triazine Nanospheres: A Robust Adsorbent for Mercury Removal

ACS Sustainable Chemistry & Engineering

Research paper thumbnail of Solvent Organization Around the Noncanonical Part of Tyrosine Modulates its Fluorescence Properties

Physical Chemistry Chemical Physics

Noncanonical amino acids are important molecules which enhance the functionality of proteins as w... more Noncanonical amino acids are important molecules which enhance the functionality of proteins as well as intensively used in therapeutics. In this paper, we have investigated fluorescence properties of noncanonical amino...

Research paper thumbnail of Role of Surface Phenolic-OH Groups in N-Rich Porous Organic Polymers for Enhancing the CO2 Uptake and CO2/N2 Selectivity: Experimental and Computational Studies

ACS Applied Materials & Interfaces

Research paper thumbnail of Understanding the Role of Hydrophobic Terminal in the Hydrogen Bond Network of the Aqueous Mixture of 2,2,2-Trifluoroethanol: IR, Molecular Dynamics, Quantum Chemical as Well as Atoms in Molecules Studies

The journal of physical chemistry. B, Jan 30, 2018

The aqueous mixture of 2,2,2-Trifluoroethanol (TFE) is one of the important alcoholic solvents wh... more The aqueous mixture of 2,2,2-Trifluoroethanol (TFE) is one of the important alcoholic solvents which has been extensively used for understanding the stability of proteins as well as several chemical reactions. In this paper, the deconvolution of the IR lines in the OH stretching region has been applied to understand the local structure of water-water, alcohol-water and alcohol-alcohol interactions in the water mixture of TFE and ethanol (ETH). Further, MD simulation, quantum chemical and atoms in molecules calculations have been performed to encode the local structure information obtained from the experimental data. Addition of small amount of alcohol in the pure aqueous medium enhances the aggregation of water molecules for the case of ETH whereas, the hydrogen bond between TFE and water is dominant contributor for TFE. The -CF3 substitution changes the orientation and hydrogen bonding site of water molecules from the hydrophilic OH terminal to the hydrophobic -CF3 terminal of TFE ...

Research paper thumbnail of Hydrophobic fluorine mediated switching of the hydrogen bonding site as well as orientation of water molecules in the aqueous mixture of monofluoroethanol: IR, molecular dynamics and quantum chemical studies

Phys. Chem. Chem. Phys.

Fluorination of ethanol changes orientation of water in its aqueous mixture.

Research paper thumbnail of A combined molecular dynamics simulation, atoms in molecule analysis and IR study on the biologically important bulk fluorinated ethanols to understand the role of weak interactions in their cluster formation and hydrogen bond network

Journal of Molecular Liquids

Research paper thumbnail of Role of Dispersive Fluorous Interaction in the Solvation Dynamics of the Perfluoro Group Containing Molecules

The journal of physical chemistry. B, Aug 17, 2017

Perfluoro group containing molecules possess an important self-aggregation property through the f... more Perfluoro group containing molecules possess an important self-aggregation property through the fluorous (F···F) interaction which makes them useful for diverse applications such as medicinal chemistry, separation techniques, polymer technology, and biology. In this article, we have investigated the solvation dynamics of coumarin-153 (C153) and coumarin-6H (C6H) in ethanol (ETH), 2-fluoroethanol (MFE), and 2,2,2-trifluoroethanol (TFE) using the femtosecond upconversion technique and molecular dynamics (MD) simulation to understand the role of fluorous interaction between the solute and solvent molecules in the solvation dynamics of perfluoro group containing molecules. The femtosecond upconversion data show that the time scales of solvation dynamics of C6H in ETH, MFE, and TFE are approximately the same whereas the solvation dynamics of C153 in TFE is slow as compared to that of ETH and MFE. It has also been observed that the time scale of solvation dynamics of C6H in ETH and MFE is...

Research paper thumbnail of Combined Molecular Dynamics, Atoms in Molecules, and IR Studies of the Bulk Monofluoroethanol and Bulk Ethanol To Understand the Role of Organic Fluorine in the Hydrogen Bond Network

The journal of physical chemistry. A, 2017

The presence of the fluorocarbon group in fluorinated alcohols makes them an important class of m... more The presence of the fluorocarbon group in fluorinated alcohols makes them an important class of molecules that have diverse applications in the field of separation techniques, synthetic chemistry, polymer industry, and biology. In this paper, we have performed the density function theory calculation along with atom in molecule analysis, molecular dynamics simulation, and IR measurements of bulk monofluoroethanol (MFE) and compared them with the data for bulk ethanol (ETH) to understand the effect of the fluorocarbon group in the structure and the hydrogen bond network of bulk MFE. It has been found that the intramolecular O-H···F hydrogen bond is almost absent in bulk MFE. Molecular dynamics simulation and density function theory calculation along with atom in molecule analysis clearly depict that in the case of bulk MFE, a significant amount of intermolecular O-H···F and C-H···F hydrogen bonds are present along with the intermolecular O-H···O hydrogen bond. The presence of intermol...

Research paper thumbnail of Role of Hydrogen Bond in the Solvation Behavior of the Binary Mixtures Containing Fluorocarbon Alcohol Molecules and Chloroform: An Experimental and Theoretical Study

Research paper thumbnail of Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents

The Journal of chemical physics, Jan 14, 2016

The self-aggregation property of the perfluoro group containing molecules makes it important in t... more The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that t...

Research paper thumbnail of Effect of microhydration on the atmospherically important metastable carbonyl sulfide anion: Structure, energetic, and infrared study

International Journal of Quantum Chemistry, 2015

ABSTRACT

Research paper thumbnail of A Theoretical Study on the Microhydration of Atmospherically Important Carbonyl Sulfide in Its Neutral and Anionic Form: Bridging the Gap Between the Bulk and Finite Size Microhydrated Cluster

The journal of physical chemistry. A, Jan 25, 2015

Carbonyl sulfide (OCS) is the most abundant and stable sulfur containing triatomic gas present in... more Carbonyl sulfide (OCS) is the most abundant and stable sulfur containing triatomic gas present in the atmosphere which plays an important role in the aerosol formation. Structure, energetics and photoelectron spectral properties of the microhydrated OCS in its neutral and anionic form have been studied by using the BP86, B3LYP and MP2 methods. OCS is linear in the neutral state whereas bent in the anionic state. Water binds with the OCS through a single hydrogen bond (O-H····O) in the OCS-(H2O)n [n=1-6] whereas binding of OCS‾ with water takes place through single as well as double hydrogen bond (O-H····S and O-H····O). Energy decomposition analysis shows that electrostatic and exchange energies are the main contributors to the stabilization energy of the microhydrated OCS and OCS‾ clusters. Detachment as well as solvation energies are calculated with different levels of theory and compared with the existing experimental values. Finally, an analytical expression has been used to obt...

Research paper thumbnail of Two-dimensional IR spectroscopy reveals a hidden Fermi resonance band in the azido stretch spectrum of β-azidoalanine

Physical Chemistry Chemical Physics

The 2D-IR spectrum of Ala-N3 shows cross-peak, but cannot be identified clearly. The 1D slice spe... more The 2D-IR spectrum of Ala-N3 shows cross-peak, but cannot be identified clearly. The 1D slice spectra obtained from 2D-IR spectrum reveals the presence of hidden Fermi resonance peak.

Research paper thumbnail of Thioether-functionalized Covalent Triazine Nanospheres: A Robust Adsorbent for Mercury Removal

ACS Sustainable Chemistry & Engineering

Research paper thumbnail of Solvent Organization Around the Noncanonical Part of Tyrosine Modulates its Fluorescence Properties

Physical Chemistry Chemical Physics

Noncanonical amino acids are important molecules which enhance the functionality of proteins as w... more Noncanonical amino acids are important molecules which enhance the functionality of proteins as well as intensively used in therapeutics. In this paper, we have investigated fluorescence properties of noncanonical amino...

Research paper thumbnail of Role of Surface Phenolic-OH Groups in N-Rich Porous Organic Polymers for Enhancing the CO2 Uptake and CO2/N2 Selectivity: Experimental and Computational Studies

ACS Applied Materials & Interfaces

Research paper thumbnail of Understanding the Role of Hydrophobic Terminal in the Hydrogen Bond Network of the Aqueous Mixture of 2,2,2-Trifluoroethanol: IR, Molecular Dynamics, Quantum Chemical as Well as Atoms in Molecules Studies

The journal of physical chemistry. B, Jan 30, 2018

The aqueous mixture of 2,2,2-Trifluoroethanol (TFE) is one of the important alcoholic solvents wh... more The aqueous mixture of 2,2,2-Trifluoroethanol (TFE) is one of the important alcoholic solvents which has been extensively used for understanding the stability of proteins as well as several chemical reactions. In this paper, the deconvolution of the IR lines in the OH stretching region has been applied to understand the local structure of water-water, alcohol-water and alcohol-alcohol interactions in the water mixture of TFE and ethanol (ETH). Further, MD simulation, quantum chemical and atoms in molecules calculations have been performed to encode the local structure information obtained from the experimental data. Addition of small amount of alcohol in the pure aqueous medium enhances the aggregation of water molecules for the case of ETH whereas, the hydrogen bond between TFE and water is dominant contributor for TFE. The -CF3 substitution changes the orientation and hydrogen bonding site of water molecules from the hydrophilic OH terminal to the hydrophobic -CF3 terminal of TFE ...

Research paper thumbnail of Hydrophobic fluorine mediated switching of the hydrogen bonding site as well as orientation of water molecules in the aqueous mixture of monofluoroethanol: IR, molecular dynamics and quantum chemical studies

Phys. Chem. Chem. Phys.

Fluorination of ethanol changes orientation of water in its aqueous mixture.

Research paper thumbnail of A combined molecular dynamics simulation, atoms in molecule analysis and IR study on the biologically important bulk fluorinated ethanols to understand the role of weak interactions in their cluster formation and hydrogen bond network

Journal of Molecular Liquids

Research paper thumbnail of Role of Dispersive Fluorous Interaction in the Solvation Dynamics of the Perfluoro Group Containing Molecules

The journal of physical chemistry. B, Aug 17, 2017

Perfluoro group containing molecules possess an important self-aggregation property through the f... more Perfluoro group containing molecules possess an important self-aggregation property through the fluorous (F···F) interaction which makes them useful for diverse applications such as medicinal chemistry, separation techniques, polymer technology, and biology. In this article, we have investigated the solvation dynamics of coumarin-153 (C153) and coumarin-6H (C6H) in ethanol (ETH), 2-fluoroethanol (MFE), and 2,2,2-trifluoroethanol (TFE) using the femtosecond upconversion technique and molecular dynamics (MD) simulation to understand the role of fluorous interaction between the solute and solvent molecules in the solvation dynamics of perfluoro group containing molecules. The femtosecond upconversion data show that the time scales of solvation dynamics of C6H in ETH, MFE, and TFE are approximately the same whereas the solvation dynamics of C153 in TFE is slow as compared to that of ETH and MFE. It has also been observed that the time scale of solvation dynamics of C6H in ETH and MFE is...

Research paper thumbnail of Combined Molecular Dynamics, Atoms in Molecules, and IR Studies of the Bulk Monofluoroethanol and Bulk Ethanol To Understand the Role of Organic Fluorine in the Hydrogen Bond Network

The journal of physical chemistry. A, 2017

The presence of the fluorocarbon group in fluorinated alcohols makes them an important class of m... more The presence of the fluorocarbon group in fluorinated alcohols makes them an important class of molecules that have diverse applications in the field of separation techniques, synthetic chemistry, polymer industry, and biology. In this paper, we have performed the density function theory calculation along with atom in molecule analysis, molecular dynamics simulation, and IR measurements of bulk monofluoroethanol (MFE) and compared them with the data for bulk ethanol (ETH) to understand the effect of the fluorocarbon group in the structure and the hydrogen bond network of bulk MFE. It has been found that the intramolecular O-H···F hydrogen bond is almost absent in bulk MFE. Molecular dynamics simulation and density function theory calculation along with atom in molecule analysis clearly depict that in the case of bulk MFE, a significant amount of intermolecular O-H···F and C-H···F hydrogen bonds are present along with the intermolecular O-H···O hydrogen bond. The presence of intermol...

Research paper thumbnail of Role of Hydrogen Bond in the Solvation Behavior of the Binary Mixtures Containing Fluorocarbon Alcohol Molecules and Chloroform: An Experimental and Theoretical Study

Research paper thumbnail of Solvent organization around the perfluoro group of coumarin 153 governs its photophysical properties: An experimental and simulation study of coumarin dyes in ethanol as well as fluorinated ethanol solvents

The Journal of chemical physics, Jan 14, 2016

The self-aggregation property of the perfluoro group containing molecules makes it important in t... more The self-aggregation property of the perfluoro group containing molecules makes it important in the research fields of biology and polymer and organic synthesis. In the quest of understanding the role of the perfluoro group on the photophysical properties of perfluoro-containing molecules in biologically important fluoroethanol solvents, we have applied photophysical as well as molecular dynamics simulation techniques to explore the properties of perfluoro groups containing molecule coumarin-153 (C153) in ethanol (ETH), monofluoroethanol (MFE), difluoroethanol (DFE), and trifluoroethanol (TFE) and compared them with the molecules without perfluoro moiety, namely coumarin-6H (C6H) and coumarin-480 (C480). In contrast to C6H and C480, the excited state lifetime of C153 in fluorinated ETHs is not monotonic. The excited state lifetime of C153 decreases in MFE and DFE as compared to ETH, whereas in TFE, it increases as compared to MFE and DFE. Molecular dynamics simulation reveals that t...

Research paper thumbnail of Effect of microhydration on the atmospherically important metastable carbonyl sulfide anion: Structure, energetic, and infrared study

International Journal of Quantum Chemistry, 2015

ABSTRACT

Research paper thumbnail of A Theoretical Study on the Microhydration of Atmospherically Important Carbonyl Sulfide in Its Neutral and Anionic Form: Bridging the Gap Between the Bulk and Finite Size Microhydrated Cluster

The journal of physical chemistry. A, Jan 25, 2015

Carbonyl sulfide (OCS) is the most abundant and stable sulfur containing triatomic gas present in... more Carbonyl sulfide (OCS) is the most abundant and stable sulfur containing triatomic gas present in the atmosphere which plays an important role in the aerosol formation. Structure, energetics and photoelectron spectral properties of the microhydrated OCS in its neutral and anionic form have been studied by using the BP86, B3LYP and MP2 methods. OCS is linear in the neutral state whereas bent in the anionic state. Water binds with the OCS through a single hydrogen bond (O-H····O) in the OCS-(H2O)n [n=1-6] whereas binding of OCS‾ with water takes place through single as well as double hydrogen bond (O-H····S and O-H····O). Energy decomposition analysis shows that electrostatic and exchange energies are the main contributors to the stabilization energy of the microhydrated OCS and OCS‾ clusters. Detachment as well as solvation energies are calculated with different levels of theory and compared with the existing experimental values. Finally, an analytical expression has been used to obt...