1. Journal Articles
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Item Trifluoromethyl-quinolin-yl-thio-propanohydrazide as an effective inhibitor of mild steel corrosion in HCl solution(2006) Ramesh, Saliyan, V.; Adhikari, A.V.3-{[8-(trifluoromethyl)quinolin-4-yl]thio}propanohydrazide(TFQTPH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in 1 M HCl and 2 M HCl solution using different techniques: potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that TFQTPH is an excellent inhibitor for mild steel in acid medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. In the temperature range 20� to 60� C, the TFQTPH adsorption follows Langmuir isotherm model. The protection efficiency increased with increasing inhibitor concentration (10 to 500 ppm), even at higher temperature also, it recorded good inhibition efficiency. � 2006 SAEST.Item Trihydrazone functionalized cyanopyridine discoids: Synthesis, mesogenic and optical properties(2014) Ahipa, T.N.; Adhikari, A.V.A new series of trihydrazone functionalized cyanopyridine derivatives (CPTH-Dm) carrying 3,4-dialkoxyphenyl groups was designed and synthesized successfully as discotic columnar liquid crystals. These new discoid mesogens display hexagonal columnar phase with a wide mesophase range from ambient temperature to 110 C and the observed columnar assembly is due to the presence of intermolecular hydrogen bonds and ?-? interactions in them. Their optical studies reveal that the compounds are good blue light emitters and hence they are potential candidates for OLED device fabrication. � 2013 Elsevier Ltd. All rights reserved.Item Z-scan and degenerate four wave mixing studies on newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units(2006) Kiran, A.J.; Udayakumar, D.; Chandrasekharan, K.; Adhikari, A.V.; Shashikala, H.D.The third-order nonlinear optical properties of newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units have been studied in DMF solution at 532 nm by using single beam Z-scan and degenerate four wave mixing techniques with nanosecond laser pulses. The variation of nonlinear response among the copolymers clearly indicates the dependence of ?(3) on donor and acceptor type of units present in the copolymers. The nonlinear refractive index, n2, of the investigated copolymers is found to be negative and the magnitude is as high as 10-10 esu. All samples exhibit strong reverse saturation absorption at the wavelength used and show good optical limiting of nanosecond pulses. The concentration dependence of n2 and the two-photon absorption coefficient (?) has been studied. � 2006 IOP Publishing Ltd.Item Solvent-free synthesis of bis-hydrazones through 1,3-dipolar cycloaddition of sydnone and study of their optical, molecular docking, and antioxidant properties(2018) Asma; Kalluraya, B.; Manju, N.; Adhikari, A.V.; Chandra; Mahendra, M.A series of new 1-(aryl)-1H-pyrazol-3,4-bis (aryl)-3,4-dicarbohydrazones (4) was obtained by the condensation of 1-arylpyrazole-3,4-dicarbohydrazides (3) with various aryl aldehydes under solvent-free conditions. The structures of the newly synthesized hydrazones were confirmed by proton-nuclear magnetic resonance spectroscopy, infrared spectroscopy, liquid chromatography mass spectrometry, elemental analysis, and by single crystal X-ray diffraction. All the synthesized compounds were screened for their antioxidant activity, where compound 4a has shown percentage inhibition higher than the standard butylated hydroxyanisole. The molecular docking and photophysical property were also investigated. 2018 Connect Journals.Item Solvent selection for highly reproducible carbon-based mixed-cation hybrid lead halide perovskite solar cells via adduct approach(2020) Keremane, K.S.; Prathapani, S.; Haur, L.J.; Bahulayan, D.; Adhikari, A.V.; Priyadarshi, A.; Dr.; Mhaisalkar, S.G.; Prof.The major problem identified in carbon-based mixed cation perovskite solar cells (PSCs) is the selection of a suitable solvent for single-step solution-processed perovskite deposition in order to promote their scalable production. Herein we report a detailed study on the selection of appropriate solvent for the one-step deposition of cesium-formamidinium lead iodide (Cs0.1FA0.9PbI3) perovskite via Lewis acid-base adduct approach for fully printable mesoporous PSCs with mesoporous TiO2/ZrO2/C architecture. Highly reproducible Cs0.1FA0.9PbI3 solar cells were fabricated via adducts of PbI2 with eco-friendly dimethyl sulfoxide (DMSO). The best cells fabricated with the above approach yielded a photoconversion efficiency (PCE) of 12.33% for a small area device (active area: 0.09 cm2) and 10.1% for a large area device (active area 0.7cm2). The average power conversion efficiency for 62 PSCs was found to be 10.5% under an AM 1.5G illumination. Finally, the mixed cation perovskite in carbon architecture using the Lewis acid-base adduct approach is remarkably stable, with less than 1% change from the initial PCE after 1800h of storage under dark ambient conditions (25 C, 60 70% RH). 2020 International Solar Energy SocietyItem Third-order nonlinear optical susceptibilities of new copolymers containing alternate 3,4-dialkoxythiophene and (1,3,4-oxadiazolyl)pyridine moieties(2009) Hegde, P.K.; Adhikari, A.V.; Manjunatha, M.G.; Poornesh, P.; Umesh, G.A new series of conjugated copolymers (P1-P3) consisting of alternate 3,4-dialkoxythiophene and (1,3,4-oxadiazolyl)pyridine moieties have been synthesized using the precursor polyhydrazide route. They have been characterized by FTIR, 1H NMR spectral and elemental analyses. These copolymers possess well defined structure and exhibit good thermal stability with the onset decomposition temperature in nitrogen at around 300 C. Their molecular weights were determined by gel permeation chromatography (GPC). The optical and charge-transporting properties of the copolymers were investigated by UV-visible spectroscopy, fluorescence emission spectroscopy and cyclic voltammetry. Their UV-visible absorption spectra showed a ?max at around 342 nm and displayed bluish-green fluorescence in solution state. The band gaps were found to be at about 2.55 eV for all the copolymers. The third-order nonlinear optical properties (NLO) of these copolymers were studied by Z-scan technique. The measurements were performed at 532 nm with 7 ns laser pulses using a Nd:YAG laser in solution form. The real part of ?(3) were estimated to be -0.881 10-12, -0.901 10-12 and -1.030 10-12 esu for P1, P2 and P3 respectively. The imaginary part of ?(3) for the copolymers P1, P2 and P3 were determined to be 0.192 10-12, 0.253 10-12 and 0.272 10-12 esu respectively. The copolymers exhibit strong reverse saturable absorption and good optical limiting behaviour at 532 nm. 2008 Elsevier B.V. All rights reserved.Item Third-order nonlinear optical studies of newly synthesized polyoxadiazoles containing 3,4-dialkoxythiophenes(2006) Udayakumar, D.; John, Kiran, A.; Adhikari, A.V.; Chandrasekharan, K.; Umesh, G.; Shashikala, H.D.The third-order nonlinear optical properties of newly synthesized soluble polyoxadiazoles containing 3,4-dialkoxythiophenes were investigated by using Z-scan and degenerate four-wave mixing (DFWM) techniques. The measurements were performed at 532 nm with 7 ns pulses from a Nd:YAG laser. We found a good agreement between the values of ?(3) determined from both the experiments. Z-scan results indicate a negative nonlinear refractive index, n2, whose magnitude is of the order of 10-10 esu for all the copolymers. The variation of nonlinear response among the copolymers clearly indicates the dependence of ?(3) on donor and acceptor type of units present in these copolymers. The copolymers exhibit strong reverse saturable absorption and good optical limiting properties at 532 nm. 2006 Elsevier B.V. All rights reserved.Item Synthesis, structural analysis and solvatochromic behaviour of 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile mesogen(2013) Ahipa, T.N.; Kumar, V.; Adhikari, A.V.In this communication, we report the synthesis and characterisation of a new luminescent liquid crystalline material, 4,6-bis (4-butoxyphenyl)-2-methoxynicotinonitrile (3). We have confirmed its structure by Fourier transform infrared and 1H nuclear magnetic resonance spectroscopy, elemental analysis and X-ray single crystal diffraction studies. The newly synthesised compound crystallises in a monoclinic system with the space group C2/c and its cell parameters are found to be a = 25.181(4) , b = 15.651(4) , c = 12.703(19) , V = 4880.4 (16) , Z = 8. The results indicate that the presence of weak CH... O and CH... N hydrogen bonding as short-range intermolecular interactions are responsible for the formation of its crystal assembly. The measured torsion angle shows the existence of a distorted structure for the molecule wherein 4-butoxyphenylene ring substituent at the fourth position of the central pyridine ring forms a torsion angle ?[C(4), C(3), C(10), C(19)] of 40.55 . Its liquid crystalline behaviour was investigated with the aid of polarised optical microscopy and differential scanning calorimetry. The study reveals that the compound displays a broad nematic phase in the range of 78-112 C. Further, solution phase optical studies indicate that it is a blue light emitter in different non-polar and polar organic solvents at a concentration of 10-5M. 2013 Copyright Taylor and Francis Group, LLC.Item Synthesis, electrochemical and optical studies of new cyanopyridine based conjugated polymers as potential fluorescent materials(2011) Vishnumurthy, K.A.; Sunitha, M.S.; Safakath, K.; Philip, R.; Adhikari, A.V.In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) carrying cyanopyridine in their backbone via Wittig condensation technique. Their structures were well established by FTIR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with the onset decomposition temperature around 300-350 C in nitrogen atmosphere. Further, their electrochemical, linear and third-order non-linear optical properties have been investigated. The polymers showed low electrochemical band gaps in the range of 1.77-1.99 eV and displayed very good fluorescence emission property in various polar solvents. The fluorescence quantum yields of polymers P1-P4 in tetrahydrofuran (THF) were found to be 35, 42, 38 and 34%, respectively. The effective two-photon absorption coefficients (?) for the polymers were determined by Z-Scan technique and were found to be 1.34 10 -11, 1.24 10-11, 3.04 10-11 and 1.85 10-11 m/W for polymers P1-P4, respectively. 2011 Elsevier Ltd. All rights reserved.Item Synthesis of some new pyrazolines and isoxazoles carrying 4-methylthiophenyl moiety as potential analgesic and antiinflammatory agents(2009) Karabasanagouda, T.; Adhikari, A.V.; Girisha, M.A series of new pyrazolines 3a-m and isoxazoies 4a-k have been synthesized from 4-acetylthioanisole, 1 with aryl aldehydes through ?, ?-unsaturated ketones. The structures of the newly synthesized compounds have been confirmed on the basis of elemental analysis and spectral studies. The newly synthesized title compounds have been tested for their analgesic and antiinflammatory activity. Some of the compounds exhibited encouraging results.