1. Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/1/6
Browse
66 results
Search Results
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 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, anticonvulsant and anti-inflammatory studies of new 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones(2013) Ulloora, S.; Shabaraya, R.; Ranganathan, R.; Adhikari, A.V.The present work involves design and synthesis of new substituted 1,4-dihydropyridin-4-yl-phenoxyacetohydrazones (4a-s, 5a-h), starting from 4-hydroxybenzaldehyde. The final compounds were screened for their in vivo anticonvulsant activity by MES, scPTZ and 6 Hz methods, while their anti-inflammatory screening was performed by Carrageenan induced Paw Edema method. The results indicated that compounds carrying electron donating groups are anticonvulsant active, while most of the tested compounds exhibited significant anti-inflammatory activity. Compounds 4k, l, 4p-s, and 5c showed rapid anti-inflammatory activity within 30 min and appeared as lead compounds. Further, Neurotoxicity study revealed that all the tested compounds are non-toxic up to 300 mg/kg doses. Selected compounds were also subjected to analgesic screening following Tail immersion method and they exhibited good activity. 2013 Elsevier Masson SAS. All rights reserved.Item Synthesis of some new 2-(3-methyl-7-substituted-2-oxoquinoxalinyl)-5-(aryl) -1,3,4-oxadiazoles as potential non-steroidal anti-inflammatory and analgesic agents(2008) Wagle, S.; Adhikari, A.V.; Kumari, N.S.Ethyl (3-methyl-7-substituted-2-oxoquinoxalin-1(2H)-yl) acetates 2a-c are prepared by the condensation of ethyl chloroacetate with 3-methyl-7-substituted quinoxalin-2(1H)-ones 1a-c. The reaction of 2a-c with hydrazine hydrate furnished 2-(3-methyl-7-substituted-2-oxoquinoxalin-1(2H)-yl) acetohydrazides 3a-c, which on cyclisation with substituted aromatic carboxylic acids in the presence of phosphorous oxychloride give 3-methyl-7-substituted-1-[(5-aryl-1,3, 4-oxadiazol-2-yl)methyl]quinoxalin-2(1H)-ones 4a-y. Further, the compounds 3a-c on cyclisation with carbon disulphide in methanolic potassium hydroxide yielded 1-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-3-methyl-7-substituted quinoxalin-2(1H)-ones 5a-c. Finally, the compounds 5a-c are converted to 3-methyl-7-substituted-1-{[5-(alkylsulfanyl)-1,3,4-oxadiazol-2-yl]methyl} quinoxalin-2(1H)-ones 6a-i by reacting them with different alkyl halides. The newly synthesized compounds have been characterized by IR, 1H NMR, 13C NMR and mass spectral data and elemental analysis. Selected compounds are screened for in vivo anti-inflammatory and analgesic activity. Few of them exhibited promising activity.Item Synthesis and two-photon absorption property of new ? -conjugated donor-acceptor polymers carrying different heteroaromatics(2013) Sunitha, M.S.; Vishnumurthy, K.A.; Adhikari, A.V.In this communication, we report the synthesis of three newly designed fluorescent polymers P1-P3, starting from simple thiophene derivatives through precursor polyhydrazide route. The new polymers, carrying donor and acceptor heterocyclic moieties with different spacer groups were found to be thermally stable and good of nonlinear optical (NLO) materials with two photon absorption property. The structures of newly synthesized monomers and polymers were confirmed by FTIR, NMR spectral and elemental analyses. Further, polymers were characterized by GPC and TGA studies. Their linear optical and electrochemical properties were evaluated by UV-vis, fluorescence spectroscopic and cyclic voltammetric (CV) studies, respectively, whereas their NLO properties were studied by Z-scan technique using Nd: YAG laser at 532 nm with 7 ns pulse. The electrochemical band gap of P1-P3 was determined to be 1.98, 1.91 and 2.05 eV, respectively. The NLO results reveal that polymers P1-P3 show good optical limiting property with TPA coefficient values 2.9 10 - 11 m/W, 8.0 10 - 11 m/W and 1.4 10 - 11 m/W, respectively. 2013 Indian Academy of Sciences.Item Synthesis and photovoltaic performance of a novel asymmetric dual-channel co-sensitizer for dye-sensitized solar cell beyond 10% efficiency(2017) Babu, D.D.; Su, R.; Naik, P.; El-Shafei, A.; Adhikari, A.V.In this paper, we report the design and synthesis of a new bi-anchoring indole based co-sensitizer DBA-8 with A-?-D-A (acceptor-? bridge-donor-acceptor) architecture, carrying indole moiety as a donor and barbituric acid as acceptor/anchoring groups. Its photo-physical and electrochemical properties along with molecular geometries, calculated from Density Functional Theory (DFT) are employed to comprehend the effect of co-sensitizer structure on photovoltaic characteristics of DSSCs. The abovementioned organic dye (DBA-8) was employed as a co-sensitizer along with well-known ruthenium based sensitizer NCSU-10 in order to broaden the spectral responses of the co-sensitized DSSC. In the present work, for the first time we are demonstrating the profound role of a dual-anchoring co-sensitizer that can play in ameliorating the overall performance of a solar cell. The photovoltaic studies indicated that, the co-sensitizer DBA-8 succeeded in increasing the light harvesting ability in the device significantly. Notably, the device co-sensitized using 0.2 mM DBA-8 along with ruthenium based chromophore NCSU-10, showed a maximum efficiency of 10.68% (Jsc = 25.14 mAcm?2, Voc = 0.695 V, ff = 61.2%). Further, the good agreement between the theoretically and experimentally obtained ?max data vindicate that, the energy functional and basis set employed in this study can be successfully utilized for predicting the absorption spectra of new photosensitizers, with great precision before synthesis. Furthermore, all these findings showcase the vast potential of bi-anchoring molecules in improving the overall performance of the dye-sensitized solar cells. 2017 Elsevier Ltd