Browsing by Author "Vasudeva Adhikari, A.V."

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2-Methoxypyridine derivatives: Synthesis, liquid crystalline and photo-physical properties
(Royal Society of Chemistry, 2014) Ahipa, T.N.; Vasudeva Adhikari, A.V.
We herein report the design and synthesis of fourteen new bent shaped luminescent mesogens carrying a pyridine core substituted with various polar groups. They possess a slightly non-planar bent conformation with various intermolecular interactions, as evidenced by their single crystal X-ray diffraction study, and exhibit an ambient to elevated temperature liquid crystalline phase (N or Colr), which has been confirmed by differential scanning calorimetry, polarized optical microscopy, and powder X-ray diffraction techniques. In these compounds, the nature of polar substituents influences significantly the formation of the mesophase over a wide thermal range. The appearance of the nematic phase is due to the presence of the lateral CN group attached to the pyridine core and the terminal F or Cl substituent. The formation of a rectangular columnar phase is attributed to the absence of the lateral CN group in the pyridine core and the presence of the terminal Br, NO2 or 4-pyridyl group. © 2014 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
3,3?-Benzene-1,4-diylbis[1-(substituted)phenylprop-2-en-1-one] derivatives: A new class of materials for third-order nonlinear optical applications
(2010) Poornesh, P.; Ravi, K.; Umesh, G.; Hegde, P.K.; Manjunatha, M.G.; Manjunatha, K.B.; Vasudeva Adhikari, A.V.
We have investigated the third-order nonlinear optical parameters of Bischalcones embedded in DMF solution and in solid PMMA matrix, by Z-scan technique using nanosecond laser pulse trains at 532 nm. Z-scan results reveal that the Bischalcones exhibits negative nonlinear refractive index as high as 10-11 esu. The molecular two-photon absorption cross-section ?2? of Bischalcones were of the order 10-46 cm4 s/photon, which is nearly two orders of magnitude larger than that of Rhodamine 6G which is 10-48 - 10-50 cm4 s/photon. We found that, the two-photon absorption (TPA) is the dominating nonlinear process leading to nonlinear absorption in both the cases in solution and as well as in solid medium. Based on TPA process, the Bischalcones exhibit good optical power limiting of nanosecond laser pulses at the input wavelength. The nonlinear optical parameters found to increase on enhancing the strength of the electron donor groups indicating the dependence and importance of electron donor/acceptor units on third-order nonlinear optical susceptibility ?(3). © 2009 Elsevier B.V. All rights reserved.
A new class of anticonvulsants possessing 6 Hz activity: 3,4-Dialkyloxy thiophene bishydrazones
(2009) Kulandasamy, R.; Vasudeva Adhikari, A.V.; Stables, J.P.
Thirty nine new 3,4-di(substituted)oxy-N2,N5-bis(substituted)thiophene-2,5-dicarbohydrazides were synthesized starting from ethyl thiodiglycolate through multi-step reactions. In the synthetic sequence, 3,4-dihydroxythiophene-2,5-diester (1) was obtained by condensing the ethyl thiodiglycolate with diethyl oxalate. It was derivatized using different alkyl halides to give disubstituted thiophene esters (2-5), which were then converted to corresponding hydrazides (6-9) following usual methods. Finally, these hydrazides, on treatment with various substituted carbonyl compounds underwent smooth condensation to yield target hydrazones (10-13). The new compounds were characterized using FT-IR, 1H NMR and 13C NMR, mass spectral and elemental analyses. The anticonvulsant activity of the title compounds was established after intraperitoneal (ip) administration in three seizure models, which include maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and 6 Hz screens and their neurotoxicity was also evaluated. Compound 11f has emerged as an active compound with no neurotoxicity in this series. Also, the structure-activity relationship of the tested compounds was discussed. © 2009 Elsevier Masson SAS. All rights reserved.
A new donor-acceptor type conjugative poly{2-[4-(1-cyanoethenyl)phenyl]-3- (3,4-didodecyloxythiophen-2-yl)prop-2-enenitrile}: Synthesis and NLO studies
(2010) Hegde, P.K.; Vasudeva Adhikari, A.V.; Manjunatha, M.G.; Suchand Sandeep, C.S.; Philip, R.
This research article describes a technique to synthesize a new donor-acceptor type conjugated polymer carrying cyanophenylenevinylene and 3,4-didodecyloxy thiophene moieties, as an effective optical limiting material. It also includes the evaluation of its linear and nonlinear optical properties and electrochemical studies. The new polymer, viz., poly{2-[4-(1-cyanoethenyl) phenyl]-3-(3,4-didodecyloxythiophen-2-yl)prop-2-enenitrile} (P1) has been synthesized starting from 2,2?-sulfanediyldiacetic acid and diethyl ethanedioate through multistep reactions. In the final step, the polymerization was brought about by Knovenagel condensation. The newly synthesized intermediate, monomer and the polymer (P1) have been characterized by different spectroscopic techniques followed by elemental analysis. Its optical and electrochemical properties are investigated by UV-vis, fluorescence spectroscopy and cyclic voltammetric studies, respectively. The red colored polymer has a well defined structure, good thermal stability and a band gap of 1.78 eV. It emits green fluorescence both in solution and in film state. The third-order nonlinear optical property (NLO) of the polymer was studied by the Z-scan technique. The measurements were performed at 532 nm with 5 ns laser pulses using samples in solution form. An absorptive nonlinearity of the optical limiting type was found in this polymer, which is due to the combined action of saturable absorption and excited state absorption processes. These studies revealed that polymer P1 is a promising material for optical limiting applications. © 2010 Elsevier B.V.
A new nonlinear optically active donor-acceptor-type conjugated polymer: Synthesis and electrochemical and optical characterization
(2010) Manjunatha, M.G.; Vasudeva Adhikari, A.V.; Hegde, P.K.; Suchand Sandeep, C.S.S.; Philip, R.
A new donor-acceptor-type poly[3-{5-[3,4-didodecyloxy-5-(1,3,4-oxadiazol- 2-yl)thiophen-2-yl]-1,3,4-oxadiazol-2-yl}-9-dodecyl-9H-carbazole] (P) has been synthesized through multistep reactions. The new polymer P exhibited good thermal stability and film-forming behavior. The electrochemical band gap is estimated to be 2.15 eV. The polymer emits intense green fluorescence in the solid state. Third-order nonlinear optical (NLO) studies showed that the strong absorptive nonlinearity observed for the polymer is of the optical limiting type, which is due to an "effective" three-photon absorption (3PA) process. This 3PA process can have potential applications in photonic devices. The studies revealed that the new polymer P is a promising material for development of efficient optoelectronic devices. Â© 2010 TMS.
A novel narrow band gap red light-emitting cyanovinylene polymer derived from 3,4-dialkoxy thiophene for optoelectronic applications
(Springer New York LLC journals@springer-sbm.com, 2010) Manjunatha, M.G.; Vasudeva Adhikari, A.V.; Hegde, P.K.
A novel donor-acceptor type narrow band gap cyanovinylene poly{3,30-(3,4-ditetradecyloxythiene-2,5-diyl) bis[2-(thiophen-2-yl)prop-2- enenitrile]} has been designed and synthesized through multistep reactions. All the newly synthesized compounds were characterized by using FTIR and 1H NMR spectroscopy followed by elemental analyses. The polymer P is found to be thermally stable up to 300 °C under nitrogen atmosphere. The optical and charge-transporting properties of the polymer were investigated by UV-visible, fluorescence emission spectroscopic and cyclic voltammetric studies. The monomer (M) emits intense green-light in solution state and the polymer (P) exhibited intense red-fluorescence both in solution and solid state. The fluorescence quantum yield of the polymer is determined to be 43%. Cyclic voltammetric studies reveal that the polymer possesses good charge carrying property. The electrochemical band-gap is estimated to be 1.8 eV. The studies reveal that the new cyanovinylene polymer P is a promising material for the development of efficient optoelectronic devices. © Springer Science+Business Media, LLC 2009.
An Efficient Aniline-Based Co-Sensitizer for High Performance N3-Sensitized Solar Cells
(Wiley-Blackwell info@wiley.com, 2018) Naik, P.; Abdellah, I.M.; Abdel-Shakour, M.; Acharaya, M.; Pilicode, N.; El-Shafei, A.; Vasudeva Adhikari, A.V.
In this work, we report a comprehensive photovoltaic investigation of a structurally simple Donor-Acceptor (D?A) configured organic dye, N,N-PABA as an active co-sensitizer in DSSCs sensitized with well-known Ru (II) based N3 dye. This effective co-sensitizer (N,N-PABA) comprises N,N-dimethylaniline system as a donor scaffold linked with 4-aminobenzoic acid as an electron withdrawing functionality. In the present study, we have demonstrated the profound effect of concentration of sensitizer, i. e. N3 based dye as well as co-sensitizer, i. e. N,N-PABA on the photovoltaic performance characteristics of solar cells. Interestingly, the best photovoltaic performance was obtained for the co-sensitized device fabricated using 0.2 mM of N,N-PABA along with 0.3 mM of N3 sensitizer, in presence of 20 mM of CDCA. It displayed power conversion efficiency (PCE) of 5.82% with JSC of 14.35 mA.cm?2, VOC of 0.626 V and FF of 64.85%. Here, the N,N-PABA effectively filled the absorption valley, avoided the dye aggregation and reduced the charge recombination in the co-sensitized devices. Thus, the results ameliorate the role of efficient co-sensitizers to yield DSSC with improved performance by the selection of a matchable co-sensitizer at an appropriate concentration. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
An iron(iii) oxide-anchored conductive polymer-graphene ternary nanocomposite decorated disposable paper electrode for non-enzymatic detection of serotonin
(Royal Society of Chemistry, 2024) Prashanth, S.; Aziz, R.A.; Raghu, S.V.; Shim, Y.-B.; Prasad, K.; Vasudeva Adhikari, A.V.
Serotonin, also known as 5-hydroxytryptamine (5-HT), is an important neurotransmitter that regulates many physiological processes. Both low and high concentrations of 5-HT in the body are associated with several neurological disorders. Hence, there is an urgent need to develop fast, accurate, reliable, and cost-effective disposable sensors for 5-HT detection. Herein, we report the sensing of 5-HT using a disposable paper-based electrode (PPE) modified with a ternary nanocomposite comprising poly(pyrrole) (P(py)), reduced graphene oxide (rGO), and iron oxide (Fe2O3). The sensor material was well characterized in terms of its structural, morphological, and chemical attributes using electron microscopy, spectral techniques, and electrochemical studies to prove the robust formation of the electroactive ternary nanocomposite and its suitability for 5-HT detection. The developed sensor exhibited an impressive limit of detection (LOD) of 22 nM with a wide linear range of 0.01 to 500 ?M, which falls in the recommended clinically relevant range. The analytical recovery, spike sample analysis, and interference studies with ascorbic acid (AA), uric acid (UA), and epinephrine (E) showed satisfactory results, wherein the sensor could detect simultaneously both 5-HT and dopamine (DA). The potential practical utility of the developed sensor was further assessed by quantifying the concentration of 5-HT in the brain samples of Drosophila melanogaster, a versatile genetic model organism employed for modeling different neural disorders in humans, and validated by gold-standard HPLC-UV experiments. The as-fabricated single-run disposable sensor with a ternary nanocomposite exhibits excellent stability with good reproducibility and is a promising platform for identifying clinically relevant concentrations of 5-HT. © 2024 RSC.
Antimicrobial and antiinflammatory studies on some 1,2,4-triazolo[3,4-b][1, 3,4]thiadiazines and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles containing quinoxaline
(Chemical Publishing Co., 2008) Wagle, S.; Vasudeva Adhikari, A.V.; Suchetha Kumari, N.S.
The reaction of 2-(3-methyl-2-oxo quinoxalin-1(2H)-yl) acetohydrazide (1), with carbon disulphide in presence of methanolic potassium hydroxide at 0°C affords potassium dithiocarbazate (2), which on treatment with 70 % hydrazine hydrate at 100°C undergoes smooth cyclization to give 1-[(4-amino-5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-3-methyl quinoxalin-2(1H)-one (3), in good yield. This triazole has been conveniently converted into title compounds, 3-methyl-1-[(6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl) methyl]quinoxalin-2(1H)-one (4a-j), by condensing it with phenacyl bromides in ethanol at reflux temperature. In another reaction, the triazole 3 has been treated with aromatic carboxylic acids in presence of phosphorus oxychloride at 100°C to afford title compounds, 3-methyl-1-[(6-phenyl[1,2,4]triazolo[3,4-b] [1,3,4]thiadiazol-3-yl)-methyl]quinoxalin-2(1H)-one (5a-j). The prepared compounds have been characterized by IR, 1H NMR, 13C NMR and mass spectral data, followed by elemental analysis. These compounds were screened for their in vitro antibacterial activity against five pathogenic strains and antifungal activity against four fungi. Further, selected compounds were subjected to in vivo antiinflammatory activity. Few of them exhibited promising activity.
Asymmetric Dual Anchoring Sensitizers/Cosensitizers for Dye Sensitized Solar Cell Application: An Insight into Various Fundamental Processes inside the Cell
(American Chemical Society service@acs.org, 2019) Kesavan, R.; Attia, F.; Su, R.; Anees, P.; El-Shafei, A.; Vasudeva Adhikari, A.V.
To study the various fundamental processes occurring inside the dye sensitized solar cell (DSSC), we have fabricated devices employing newly synthesized diphenylamine-based organic dyes with A-D-?-A configuration, carrying four different anchoring groups, namely, cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/cosensitizers. In the present work, all the bianchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical, and theoretical studies. All of them displayed characteristic ?abs and ?emi in the range of 415-480 and 570-680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (?Ginj), recombination (?Ginj), and regeneration (?Greg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a cosensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion. © © 2019 American Chemical Society.
Carbazole based organic dyes as effective photosensitizers: A comprehensive analysis of their structure-property relationships
(John Wiley and Sons Inc, 2022) Naik, P.; Keremane, K.S.; Elmorsy, M.R.; El-Shafei, A.; Vasudeva Adhikari, A.V.
The present work describes the effect of structural modification of carbazole-based photosensitizers carrying carboxylic acid as a common anchoring functionality, on the photovoltaic parameters of newly fabricated DSSCs. In this study, we have selected our previously reported three carbazole-based derivatives, viz. S1-3 having different structural designs, that is, D-π-A (S1), D-D-π-A (S2), and A-π-D-π-A (S3) with different donor units and π-spacers, but an identical cyanoacetic acid anchoring unit. We have evaluated their optical, electrochemical, and photovoltaic behaviors in order to explore their structure-property relationships. Also, the theoretical investigations were performed to obtain a deeper understanding of their HOMO-LUMO levels, charge distribution in FMOs, directional flow of electrons within the push-pull type sensitizers, and optical behavior. Finally, the DSSCs were constructed by employing these dyes as sensitizers without any co-absorbents and the performance of the devices was evaluated by using illuminated current-voltage characteristics. Among the tested dyes, di-anchoring S3 exhibited improved PCE of 3.77 % due to its strong adsorption on the TiO2 surface that resulted in superior VOC of the cell. While the S2 containing electron-releasing anisole as an auxiliary donor exhibited better JSC value leading to the optimum PCE of 3.73 % which is comparable to that of S3. Obviously, these results validate the role of the π-spacer and additional donor of the sensitizers on the overall performance of the DSSCs. © 2021 The Authors. Electrochemical Science Advances published by Wiley-VCH GmbH.
Columnar self-assembly of novel benzylidenehydrazones and their difluoroboron complexes: Structure-property correlations
(Royal Society of Chemistry, 2019) Vinayakumara, D.R.; Swamynathan, K.; Kumar, S.; Vasudeva Adhikari, A.V.
Organoboron complexes are considered to be an important class of optically dynamic materials and because of their imperative properties, they have been unceasingly studied in a wide range of scientific areas. In this context, a new family of D-A-D? architectured boron difluoride complexes FB1-4 derived from arylhydrazones HZ1-4 has been synthesized and characterized. The work also deliberates detailed studies on their thermal, self-assembling and optoelectronic properties with respect to structural modifications. The systematic studies reveal that the new arylhydrazone ligands and their BF2 complexes exhibit a prospective columnar mesomorphism with different 2D lattice geometries at room temperature, owing to their critical structural features. Interestingly, an unusual morphological cross-over from a columnar hexagonal to rectangular mesophase has been confirmed in one of the investigated pseudo-discoidal boron complexes, FB4. The optoelectronic studies showcased their ICT dominating dye properties. Finally, the experimental results have been consciously correlated with quantum chemical simulations. © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Conductive nano nickel oxide/hydroxide paper electrochemical sensor for serotonin detection in genetically engineered Drosophila
(Royal Society of Chemistry, 2025) Prashanth, S.; Kadandelu, M.; Raghu, S.V.; Prasad, K.S.; Vasudeva Adhikari, A.V.
Serotonin is considered an integral part in neuropsychiatric diseases, such as major depressive disorder, schizophrenia, post-traumatic stress disorder, obsessive-compulsive disorder, anxiety disorder, and substance use disorder. Understanding the levels of serotonin under different disease conditions is important. Herein, we explored the development of an efficient electrochemical sensor utilizing sustainable paper electrode integrated with nanocomposites through a simultaneous electrochemical deposition strategy. The as-developed sensor is further investigated with surface and electrochemical studies to understand the robust fabrication of the sensor as well as the electrochemical characteristics to show the improved electron transfer kinetics and detection capabilities even in the presence of common interfering biomolecules. The sensor demonstrated a broad linear range from 0.007 nM to 500 ?M, with an impressive limit of detection of 0.024 nM for the low concentration range (0.007-0.48 nM) and 383.7 nM for the high concentration range both falling well within the clinically relevant detection levels of serotonin. To evaluate the practical performance, the developed sensor was tested on brain homogenates obtained from genetically modified Drosophila melanogaster models with different serotonin levels. The sensor effectively detected the in vivo changes in serotonin level, and the results were validated against gold-standard HPLC analysis and immunohistochemical staining experiments. The sensors’ notable stability, selectivity, and sensitivity towards serotonin make them a valuable tool for neurochemical research and clinical applications, particularly in studying serotonin-related neurological conditions and advancing personalized treatments. © 2025 The Royal Society of Chemistry.
Corrosion inhibition of mild steel in acid media by quinolinyl thiopropano hydrazone
(2009) Saliyan, R.V.; Vasudeva Adhikari, A.V.
3-([8-(trifluoromethyl)quinolin-4-yl]thio)-A''-(2)3,4- trihydroxybenzylidene)propano hydrazide (TQTHBH) was synthesized, characterized and tested as a corrosion inhibitor for mild steel in HC1 and H2SO4 solutions using weight loss method, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The corrosion inhibition efficiency results obtained by all the above three techniques were in good agreement with each other. Scanning electron microscopy (SEM) technique is used to confirm the effectiveness of inhibition of mild steel corrosion in acid media. The results showed that TQTHBH is a good inhibitor for mild steel in acid media. The inhibition efficiency of TQTHBH in different media was in the following order: 2 M HC1 < 1 M H2SO4 < 1 M HC1 < 0.5 M H2S04. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. The adsorption follows Langmuir isotherm. TQTHBH acts as an anodic inhibitor. The protection efficiency increased with increasing inhibitor concentration in the range 0.222 x 10"4 - 11.086 x 10^ M, also slightly increased with increasing temperature. Chemisorption mechanism is proposed. The apparent activation energies and enthalpies for the adsorption process were determined. The fundamental thermodynamic functions were used to gain information about TQTHBH inhibitory behaviour.
“Dental Cements Based on Acid Degradable Glasses/Ion Leachable Glasses” – A Review
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2016) Nagaraja Upadhya, P.; Ginjupalli, K.; Srinivasan, K.K.; Vasudeva Adhikari, A.V.; Satapathy, L.N.
Glass ionomer cement (GIC) is one of the most versatile cements used in dentistry. It came into existence in the late 1960s mainly to overcome the drawbacks of its predecessor material ‘dental silicate cements’. Since then, it has undergone several improvisations and modifications to meet the requirements of various dental applications. The GIC consists of basic glass powder and acidic polyacids, which sets by an acid-base reaction between the components. The glass component of GIC plays a major role in the clinical performance of the material. It provides the source of ions for the cement formation, controls the strength, imparts translucency and provides a therapeutic benefit by releasing fluoride. Glass structure-reactivity-processing are the three main aspects to be considered when designing the glass compositions for cement formation. From the conventional calcium fluoroaluminosilicate glass to the current aluminium free glasses, GIC has received significant attention in the recent past to further extend its applications in various fields. The purpose of this article is to provide relevant discussion on the scientific development of the GIC from the glass science and technology point of view. © 2016 The Indian Ceramic Society.
Design and synthesis of a new thiophene based donor-acceptor type conjugated polymer with large third order nonlinear optical activity
(2011) Vishnumurthy, K.A.; Vasudeva Adhikari, A.V.; Sunitha, M.S.; Ann Mary, K.A.A.; Philip, R.
In this communication we describe the design and synthesis of a new conjugated polymer (P) carrying 3,4-dialkoxythiophene, 1,3,4-oxadiazole and thienylene-vinylene units, from its monomers using Wittig condensation method. The structure of newly synthesized polymer was confirmed by FT-IR, 1H NMR, UV-vis spectral, elemental analysis and gel permeation chromatographic techniques. The polymer exhibited good thermal stability with the onset decomposition temperature around 320 °C in nitrogen atmosphere. Further, its electrochemical, linear and nonlinear optical properties have been investigated. The optical and electrochemical band gap was found to be 2.21 eV. Its third-order nonlinear optical property was investigated by Z-scan and DFWM techniques, using a Q-switched, frequency doubled Nd:YAG laser producing 7 ns laser pulses at 532 nm. Z-scan results reveal that the polymer exhibits self-defocusing nonlinearity. The operating mechanism involves reverse saturable absorption. The polymer shows strong optical limiting behavior due to effective two-photon absorption (2PA). The value of 2PA coefficient was found to be 3.0 × 10-11 mW, which is comparable to that of good optical limiting materials. The fluorescence quantum yield of the polymer in solution was determined using quinine sulfate as standard and it was found to be 35%. © 2011 Elsevier B.V. All rights reserved.
Design and Synthesis of New Amides and Thioamides Derived from 3,4-Ethylenedioxythiophene as Potential Anticonvulsants
(2010) Kulandasamy, R.; Vasudeva Adhikari, A.V.; Stables, J.P.
Five new series of 3,4-ethylenedioxythiophene derivatives carrying important pharamacophores, viz., amide, ester, ether and active secondary aryl moieties have been designed and synthesized through multistep reactions starting from thiodiglycolic ester and diethyl oxalate. They have been characterized by elemental and spectral data. All the target compounds have been screened for their anticonvulsant activity at three different models viz. maximal electroshock (MES), subcutaneous metrazole (scMET), and 6 Hz screen and evaluated for their neurotoxicity in rotorod model. Compound 6a emerged as lead with no neurotoxicity. All the five series of compounds are safe in the toxicity studies at the maximum dose of 300 mg/kg of body weight. Amongst the tested compounds, the ester pharmacophore with thioamide fragment has showed better activity than the other analogs.
Design and synthesis of new donor-acceptor type conjugated copolymers derived from thiophenes
(2009) Manjunatha, M.G.; Vasudeva Adhikari, A.V.; Hegde, P.K.
A new series of donor-acceptor type poly(thiophene) derivatives (P1-P3) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. In the final step, the polymerization was carried out using Wittig reaction. This is a good synthetic route for the preparation of any desired p- and n-type copolymers. The optical and potential charge-transporting properties of the copolymers were investigated by UV-vis, fluorescence emission spectroscopy and cyclic voltammetry. The copolymers exhibited bluish-green/green fluorescence in their thin film forms. Cyclic voltammetry experiments showed that these copolymers have low-lying LUMO energy levels ranging from -2.98 to -3.11 eV and high lying HOMO energy levels ranging from -5.45 to -5.65 eV. The optical and electrochemical studies reveal that new copolymers are new promising materials for the development of efficient polymer light emitting diodes. © 2008 Elsevier Ltd. All rights reserved.
Design and synthesis of some new quinoline-3-carbohydrazone derivatives as potential antimycobacterial agents
(Elsevier Ltd, 2010) Eswaran, S.; Vasudeva Adhikari, A.V.; Pal, N.K.; Chowdhury, I.H.
A series of 26 new quinoline derivatives carrying active pharmacophores has been synthesized and evaluated for their in vitro antituberculosis activity against Mycobacterium tuberculosis H37Rv (MTB), Mycobacterium smegmatis (MC2), and Mycobacterium fortuitum following the broth micro dilution assay method. Compounds 13e, 13i, 13k, 14a, 14c, 14i, and 14k exhibited significant minimum inhibition concentrations, when compared with first line drugs isoniazid (INH) and rifampicin (RIF) and could be ideally suited for further modifications to obtain more efficacious compounds in the fight against multi-drug resistant tuberculosis. © 2009 Elsevier Ltd. All rights reserved.
Design, synthesis and antimicrobial activities of some new quinoline derivatives carrying 1,2,3-triazole moiety
(2010) Thomas, K.D.; Vasudeva Adhikari, A.V.; Shetty, N.S.
A new series of [1-(6-methoxy-2-methylquinolin-4-yl)-1H-1,2,3-triazol-4-yl] methanamine derivatives were synthesized starting from 4-methoxyaniline through multi-step reactions. The title compounds 5a-y were prepared by treating the azide intermediate 4 with propargyl bromide and different alkyl/heterocyclic amines in a sequential three component synthesis. All the new compounds were characterized by spectral and elemental analyses. The newly synthesized final compounds were evaluated for their in vitro antibacterial and antifungal activities against pathogenic strains. The preliminary screening results indicated that most of the compounds demonstrated moderate to very good antibacterial and antifungal activities, comparable to the first-line drugs. Twenty five new derivatives of [1-(6-methoxy-2-methylquinolin-4-yl)-1H-1,2,3- triazol-4-yl] methanamine have been synthesized and the most effective compounds have MIC of 6.25 ?g/mL, which are in comparable with present antibiotics. © 2010 Elsevier Masson SAS. All rights reserved.