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111.
Four new series of achiral bent-core compounds and two biphenyl derivatives of them have been synthesised and their mesomorphic properties are studied. These mesogens are salicylaldimine derivatives, designed with an aim to study the effect of salicylaldimine group and lateral substituents, viz., ?F and ?Cl at different locations of the molecular structure, on the mesomorphic properties. The newly synthesised compounds are characterised using organic spectroscopy and elemental analysis (EA). The liquid crystalline properties of these compounds are studied using polarising optical microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical studies. They are found to exhibit dark conglomerate (DC) and B2 mesophases. The DC phases are of sponge and HNC type, and the B2 is SmCaPA in nature. The compounds, wherein the salicylaldimine group is present at the centre of the bent-core, mainly exhibit DC mesophases and when this group is present in one of the wings of the bent-core molecule, the compounds tend to show only a B2 mesophase, irrespective of the nature of lateral substituents. Many of the DC liquid crystals synthesised here retained the chirality even in their crystalline states which are confirmed by the circular dichroism spectroscopic studies. 相似文献
112.
Nirmala S. Naik Navya S. Bhat Arpana G. Hegde Swati S. Bhat Akshay Kirasur Anilkumar Patil 《合成通讯》2018,48(5):511-523
For the application in organic electronics as well as pH meters, a series of novel 2,4,6-trisubstituted pyridines have been synthesized by the reaction of substituted aromatic aldehydes and substituted 3-acetylcoumarin with ammonium acetate. The structures of all the new compounds were characterized by IR, NMR, and GC–MS analysis. The important photo physical prerequisites for organoelectronic such as optical absorption and thermal stability were determined for the synthesized molecules. Optical properties were studied by UV–visible absorption and fluorescence spectroscopy. Optical band gaps of the 2,4,6-trisubstituted pyridines were found to be around 3.01–3.06?eV as calculated from their onset absorption edge. The pH-dependent changes in the fluorescence intensity suggest that 2,4,6-trisubstituted pyridines are useful applicants in intracellular pH meters. 相似文献
113.
Malledevarapura Gurumurthy Prabhudeva Karthik Kumara Achutha Dileep Kumar Mylarappa B. Ningappa Neratur K. Lokanath Kariyappa Ajay Kumar 《Research on Chemical Intermediates》2018,44(11):6453-6468
Increasing instances of antimicrobial drug resistance and Inflammation-mediated disorders requires the design and synthesis of new small-molecules with higher affinity and specificity for their potential targets to serve as antibiotics or anti-inflammatory drugs, respectively. The current study presents the synthesis of a series of chalcones, 3(a–h) by the reaction of 3-methylthiophene-2-carbaldehyde, 1 and acetophenones, 2(a–h) by Claisen–Schmidt approach. The chalcones were efficiently transformed into thienyl-pyrazolines, 5(a–h) by their reaction with thiosemicarbazide hydrochloride, 4 in the presence of Amberlyst-15 as a catalyst in acetonitrile at room temperature. Alternatively, the compounds 5(a–h) were prepared by conventional method using acetic acid (40%) medium. Structures were characterized by spectral and single crystal X-ray diffraction studies. Preliminary assessment of the anti-inflammatory properties of the compounds showed that, amongst the series, compounds 5b and 5c have excellent anti-inflammatory activities. Further, compound 5c showed excellent activity against Escherichia coli (MIC, 15 µg/mL), Bacillus subtilis (MIC, 20 µg/mL), Aspergillus niger (MIC, 20 µg/mL), and Aspergillus flavus (MIC 15 µg/mL), respectively. Compounds 5a and 5b were also found to be active against the tested microorganisms. 相似文献
114.
115.
P. Hegde F. Karsch E. Laermann S. Shcheredin 《The European Physical Journal C - Particles and Fields》2008,55(3):423-437
We clarify the relation between the improvement of dispersion relations in the fermion sector of lattice regularized QCD and
the improvement of bulk thermodynamic observables. We show that in the infinite temperature limit the cut-off dependence in
dispersion relations can be eliminated up to (an) corrections, if the quark propagator is chosen to be rotationally invariant up to this order. In bulk thermodynamic observables
this eliminates cut-off effects up to the same order at vanishing as well as non-vanishing chemical potential. We furthermore
show that in the infinite temperature, ideal gas limit the dependence of finite cut-off corrections on the chemical potential
is given by Bernoulli polynomials which are universal as they do not depend on a particular discretization scheme. We explicitly
calculate leading and next-to-leading order cut-off corrections for some staggered and Wilson fermion type actions and compare
these with exact evaluations of the free fermion partition functions. This also includes the chirally invariant overlap and
domain wall fermion formulations.
PACS 11.15.Ha; 11.10.Wx; 12.38.Gc; 12.38.Mh 相似文献
116.
117.
Shweta Hegde Sudhir Kapoor Satyawati Joshi Tulsi Mukherjee 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,280(1-3):116-124
The effect of ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) in stabilizing different shapes of silver nanoparticles have been examined by electronic absorption spectroscopy and transmission electron microscopy. The silver nanoparticles were prepared by two methods, i.e. γ-irradiation and chemical reduction method. Two types of effects of EGTA were identified which lead to the formation of truncated triangular silver nanoplates and chain—like silver aggregates respectively. Time-dependent infrared attenuated total reflectance (ATR-FTIR) studies showed that the nature of adsorption of EGTA on the silver nanoparticle surface influences the shape of the nanoparticles. Pulse radiolysis studies showed the mechanism of formation of the initial silver nanoclusters. 相似文献
118.
A combined electrochemical method and X-ray photo electron spectroscopy (XPS) has been utilized to understand the Pd(2+)/CeO(2) interaction in Ce(1-x)Pd(x)O(2-δ) (x = 0.02). A constant positive potential (chronoamperometry) is applied to Ce(0.98)Pd(0.02)O(2-δ) working electrode which causes Ce(4+) to reduce to Ce(3+) to the extent of ~35%, while Pd remains in the +2 oxidation state. Electrochemically cycling this electrode between 0.0-1.2 V reverts back to the original state of the catalyst. This reversibility is attributed to the reversible reduction of Ce(4+) to Ce(3+) state. CeO(2) electrode with no metal component reduces to CeO(2-y) (y~0.4) after applying 1.2 V which is not reversible and the original composition of CeO(2) cannot be brought back in any electrochemical condition. During the electro-catalytic oxygen evolution reaction at a constant 1.2 V for 1000 s, Ce(0.98)Pd(0.02)O(2-δ) reaches a steady state composition with Pd in the +2 states and Ce(4+): Ce(3+) in the ratio of 0.65:0.35. This composition can be denoted as Ce(4+)(0.63)Ce(3+)(0.35)Pd(0.02)O(2-δ-y) (y~0.17). When pure CeO(2) is put under similar electrochemical condition, it never reaches the steady state composition and reduces almost to 85%. Thus, Ce(0.98)Pd(0.02)O(2-δ) forms a stable electrode for the electro-oxidation of H(2)O to O(2) unlike CeO(2) due to the metal support interaction. 相似文献
119.
Shekappa D. Lamani Rajesh N. Hegde Anita P. Savanur Sharanappa T. Nandibewoor 《Electroanalysis》2011,23(2):347-354
The voltammetric oxidation and determination of chlorpheniramine maleate (CPM) was studied at a carbon paste electrode (CPE) in the presence of sodium‐dodecyl sulfate (SDS) by cyclic and differential pulse voltammetry. The results indicated that the voltammetric response of chlorpheniramine maleate was markedly increased in the low concentration of SDS, suggesting that SDS exhibits observable enhancement effect to the determination of chlorpheniramine maleate. Under the optimal conditions the peak current was proportional to chlorpheniramine maleate concentration in the range of 8.0×10−6 to 1.0×10−4 M with detection limit of 1.7×10−6 M by differential pulse voltammetry. The proposed method was successfully applied to the determination of chlorpheniramine in pharmaceutical and urine samples. 相似文献
120.
R. K. Singhal J. Preetha Rupali Karpe P. Hema Ajay Kumar V. M. Joshi A. K. Ranade A. G. Hegde 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):301-306
During this work the determination of uranium in the range of μg·L−1 to tens of μg·L−1 was done by alpha-spectrometry after electroplating the aliquots of water sample using (NH4)2SO4 as an electrolyte. In general, the determination of uranium by alpha-spectrometry needs its separation from other transuranics
specially thorium. The process described here does not involve any sample digestion and radiochemical separation of uranium
from other transuranics. In this method an aliquot (1 to 3 mL) of the sample was dried and dissolve in (NH4)2SO4 and thereafter the sample was electroplated on a stainless steel (SS) planchet by using an electrochemical cell of special
design. The proposed techniques have a distinct advantage over the determination of uranium by adsorptive stripping voltammetry
(AdSV) in which uranium-chloranilic (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) acid complex was used for concentrating
the uranium from the solution. Since in the case of AdSv, the determination of uranium was not possible for samples having
dissolved organic carbon (DOC) more than 15 mg·L−1 and Cl− concentration is in the range of 40,000 μ·g−1. In the case of spike experiments with 232U the recovery was observed in the range of 90–95% in aqueous medium having higher concentration of Cl− and DOC as indicated above. 相似文献