Raveendra Melavanki

M S Ramaiah University of Applied Sciences

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N. R. Patil

KLE Technological University

Raviraj Kusanur

Rock Valley College

Kalpana Sharma

Bhagwant University

D. Nagaraja

International Institute of Information Technology Bangalore

Varsha V. Koppal

KLE Technological University

P. Bhavya

Central University of Tamil Nadu

J. Thipperudrappa

Sri Krishnadevaraya University

V. T. Muttannavar

H.S. Geethanjali

International Institute of Information Technology Bangalore

Jagadish S. Kadadevarmath

Karnatak University

Cooperative Institutions

Visvesvaraya Technological University

Karnatak University

M S Ramaiah University of Applied Sciences

KLE Technological University

Bangalore University

Indian Institute of Science Bangalore

International Institute of Information Technology Bangalore

KLE University

Indian Institute of Technology Dharwad

R.V. College of Engineering

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Specific interactions of alcohols and non‐alcohols with a biologically active boronic acid derivative: a spectroscopic study

Luminescence (2015)

H.S. Geethanjali Raveendra Melavanki D. Nagaraja N. R. Patil J. Thipperudrappa

The photophysical properties of 4-fluoro-2-methoxyphenyl boronic acid (4FMPBA) are characterized using absorption and fluorescence techniques in series of non-alcohols and alcohols. The results are analyzed using different solvent polarity functions and Kamlet and Catalan's multiple regression approaches. The excited state dipole moment and change in dipole moment are calculated using both the solvatochromic shift method and Reichardt's microscopic solvent polarity parameter ETN. The ground state dipole moment is evaluated using quantum chemical calculations. It is found that general solute-solvent and hydrogen bond interactions are operative in this system. A red shift of ~ 9 nm in the emission spectra is observed with an increase in the solvent polarity, which depicts π→π(*) transitions, as well as the possibility of an intramolecular charge transfer (ICT) character in the emitting singlet state of 4FMPBA. The relative quantum yield, radiative and non-radiative decay constants are calculated in alkanes and alcohols using the single point method. It is found that the quantum yield of the molecule varies from 16.81% to 50.79% with the change in solvent polarity, indicating the dependence of fluorescence on the solvent environment. Copyright © 2015 John Wiley & Sons, Ltd.

Solvatochromism

Quantum yield

10.1002/bio.3067

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Citations (6)

Static and dynamic model fluorescence quenching of laser dye by carbon tetrachloride in binary mixtures

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (2013)

Jagadish S. Kadadevarmath G.H. Malimath Raveendra Melavanki N. R. Patil

10.1016/j.saa.2013.08.053

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Citations (42)

Studies on thermodynamic properties of pure poly(ethylene glycol)-400 in the temperature range 299–363 K using volume expansivities

Polymer Bulletin (2013)

F. M. Sannaningannavar Shivaram N. Patil B. S. Navati Raveendra Melavanki N. H. Ayachit

Atmospheric temperature range

Molar mass

10.1007/s00289-013-1015-z

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Citations (6)

Solvent effect on the spectroscopic properties of 6MAMC and 7MAMC

Journal of Molecular Liquids (2010)

Raveendra Melavanki N. R. Patil S. B. Kapatkar N. H. Ayachit Siva Umapathy

Solvatochromism

Stokes shift

Bond dipole moment

10.1016/j.molliq.2010.11.002

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Citations (32)

Quenching of the excitation energy of coumarin dyes by aniline

Canadian Journal of Physics (2013)

D. Nagaraja Raveendra Melavanki N. R. Patil Raviraj Kusanur J. Thipperudrappa

Quenching mechanisms of coumarin dyes, namely 6-bromo-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin (6BDTC) and 8-methoxy-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin (8MDTC), were carried out in toluene by adopting two methods, namely steady-state and time-resolved methods, to understand the role of diffusion in the quenching mechanism. The solute molecules were excited by UV radiation of wavelength 360 and 330 nm. Various quenching parameters like frequency of encounter (k d ), probability of quenching per encounter (p and p′), and quenching rate parameter (k q and [Formula: see text]) were experimentally determined in all the solvents. Activation energy of quenching (E a and [Formula: see text]) was also determined by using the literature values of activation energy of diffusion (E d ). It was found that the values of E a (and [Formula: see text]) were less than E d indicating that the quenching reactions are more significantly influenced by diffusion.

10.1139/cjp-2013-0009

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Citations (9)

Preparation and optical parameter characterization of two aldehyde derivative thin films for photonic applications by drop casting method

Luminescence (2020)

Raveendra Melavanki S. Vaijayanthimala Basappa Chanabasappa Yallur Vikas M. Shelar Diksha Singh

Abstract In this study, thin films of polymer poly(methyl methacrylate) were prepared using a drop casting method. Two newly synthesized aldehyde derivatives, 2‐bromomalonaldehyde and 5,6‐dihydroimidazo[2,1‐b]thiazole‐2‐carbaldehyde, were used at different concentrations to dope the films. The prepared films were transparent and therefore studied for application in photonics. Optical characterization of the samples was carried out using different spectroscopy techniques. Absorption spectra for both samples were obtained using a UV–vis light spectrophotometer. Other significant optical parameters, such as refractive index, extinction coefficient, and band gap energies, were calculated from the absorption spectra. The effect of doping concentration on these parameters was studied. Emission spectra were obtained using a fluorescence spectrophotometer and the effect of doping was observed. Fourier transform infrared spectra of the doped films were obtained and compared with the pure compound to note changes in peak values and peak intensity. This present work studied the effect of doping on optical properties and examined the application of the samples for photonics.

Molar absorptivity

10.1002/bio.3800

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Citations (12)

Role of solvent polarity on the fluorescence quenching of newly synthesized 7,8-benzo-4-azidomethyl coumarin by aniline in benzene–acetonitrile mixtures

Journal of Luminescence (2007)

Raveendra Melavanki Raviraj Kusanur M.V. Kulakarni Jagadish S. Kadadevarmath

Solvent polarity

10.1016/j.jlumin.2007.08.013

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Citations (68)

Synthesis, spectroscopic characterization, electronic and docking studies on novel chalcone derivatives (3DPP and 5PPD) by experimental and DFT methods

Journal of Molecular Structure (2022)

Kalpana Sharma Raveendra Melavanki Sudhir M. Hiremath Raviraj Kusanur H.S. Geethanjali

Natural bond orbital

Chemical shift

10.1016/j.molstruc.2022.132553

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Citations (6)

Photophysical properties of thiadiazoles derivative: Estimation of ground and excited state dipole moments by theoretical and experimental approach

AIP conference proceedings (2016)

G. V. Muddapur Varsha V. Koppal N. R. Patil Raveendra Melavanki

The absorption and fluorescence spectra of newly synthesized thiadiazole derivative namely 6-(4-chlorophenyl)-2-(naphthalene-1-ylmethyl) imidazo [2, 1-b][1,3,4] thiadiazole [6CNMT] have been recorded in various solvents of different polarities. The ground state dipole moment of 6CNMT was obtained from quantum chemical calculations. Solvatochromic correlations were used to estimate the ground state (μg) and excited state (μe) dipole moments. The excited state dipole moments are observed to be greater than the ground state dipole moment. Further, the changes in dipole moment (Δμ) were calculated both from solvatochromic shift method and microscopic solvent polarity parameter (ETN) and the values are compared. The spectral variations were also analyzed by Kamlet-Taft parameters.

Solvatochromism

Bond dipole moment

10.1063/1.4946424

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Citations (7)

Solvent effect on the spectroscopic properties of 8EMOHCC

Materials Today Proceedings (2018)

P.G. Patil Varsha V. Koppal Raveendra Melavanki N. R. Patil

Solvatochromism

Bathochromic shift

10.1016/j.matpr.2018.01.065

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Citations (4)