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11.
Nagappanpillai Adarsh Madhesh Shanmugasundaram Dr. Rekha R. Avirah Dr. Danaboyina Ramaiah 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12655-12662
A new series of aza‐BODIPY derivatives ( 4 a – 4 c , 5 a , c , and 6 b , c ) were synthesized and their excited‐state properties, such as their triplet excited state and the yield of singlet‐oxygen generation, were tuned by substituting with heavy atoms, such as bromine and iodine. The effect of substitution has been studied in detail by varying the position of halogenation. The core‐substituted dyes showed high yields of the triplet excited state and high efficiencies of singlet‐oxygen generation when compared to the peripheral‐substituted systems. The dye 6 c , which was substituted with six iodine atoms on the core and peripheral phenyl ring, showed the highest quantum yields of the triplet excited state (ΦT=0.86) and of the efficiency of singlet‐oxygen generation (ΦΔ=0.80). Interestingly, these dyes were highly efficient as photooxygenation catalysts under artificial light, as well as under normal sunlight conditions. The uniqueness of these aza‐BODIPY systems is that they are stable under irradiation conditions, possess strong red‐light absorption (620–680 nm), exhibit high yields of singlet‐oxygen generation, and act as efficient and sustainable catalysts for photooxygenation reactions. 相似文献
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Achim Füngerlings Adarsh Koul Maik Dreyer Anna Rabe Dulce M. Morales Wolfgang Schuhmann Malte Behrens Rossitza Pentcheva 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17145-17158
In a combined experimental and theoretical study we assess the role of Co incorporation on the OER activity of LaCoxFe1−xO3. Phase pure perovskites were synthesized up to in 0.025/0.050 steps. HAADF STEM and EDX analysis points towards FeO2-terminated (001)-facets in LaFeO3, in accordance with the stability diagram obtained from density functional theory calculations with a Hubbard U term (DFT+U). Linear sweep voltammetry conducted in a rotating disk electrode setup shows a reduction of the OER overpotential and a nonmonotonic trend with x, with double layer capacitance measurements indicating an intrinsic nature of activity. This is supported by DFT+U results that show reduced overpotentials for both Fe and Co reaction sites with the latter reaching values of 0.32–0.40 V, ∼0.3 V lower than for Fe. This correlates with a stronger reduction of the binding energy difference of the *O and *OH intermediates towards an optimum value of 1.6 eV for , the OH deprotonation being the potential limiting step in most cases. Significant variations of the magnetic moments of both surface and subsurface Co and Fe during OER demonstrate that the beneficial effect is a result of a concerted action involving many surrounding ions, which extends the concept of the active site. 相似文献
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Sreeja Thulasi Jisha Babu Adarsh Babukuttannair Viji Sreemathi Ramavarma Luxmi Varma 《Tetrahedron》2010,66(27-28):5270-5276
A seemingly ipso-like nucleophilic substitution of the upper rim of p-tert-butylcalix[4]arene is accomplished by an indirect method involving calix[4]arene derived bis(spirodienone). This method not only provides both mono and 1,3-diaryloxy calixarenes but also enables the synthesis of upper rim monothio substituted calix[4]arenes. A modification of the methodology can be successfully extended for the selective synthesis of mono- and 1,3-diquinone calix[4]arenes having free hydroxyl groups at the lower rim, in fewer steps. 相似文献
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We report the observation of giant photo induced optical bleaching in Sb/As2S3 multilayered film at room and liquid He temperatures, when irradiated with 532 nm laser at moderate intensities. The experimental results show a dramatic increase in transmittance near the band gap regime at both the temperatures; however the rates at which transmission change occurs are rather slow at low temperature. The huge change in transmission is due to the photo induced intermixing of As2S3 layer with Sb. Our XPS measurements show that photo induced intermixing occurs through the wrong homopolar bonds, which under actinic light illumination are converted into energetically favored hetropolar bonds. 相似文献
16.
Deepak K. Dwivedi Adarsh Sahu Sachin J. Dighade Ram Kishore Agrawal 《Journal of heterocyclic chemistry》2020,57(4):1666-1671
A series of 10 p-substitutedbenzoylmethylene hydrazide derivatives 4a-j were synthesized by protecting carboxylic group of 4-hydroxybenzoic acid using methanol and sulfuric acid than reacting it with hydrazide to form 4-hydroxybenzohydrazide followed by reacting with a variety of aldehydes and evaluated for their activity against nosocomial infection. All the synthesized compounds were characterized by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), and mass spectral data. The in vitro antimicrobial potential of synthesized compounds was estimated against prominent strains of nosocomial pathogens (Staphylococcus aureus, Escherichia coli, and Aspergillus niger). The antimicrobial evaluation revealed compounds 4b , 4c , 4d , 4e , 4f , and 4j to be the most active compounds of the series with IC50 value for antibacterial in the range 0.39 to 0.75 μM/mL. Furthermore, the in vitro cytotoxic potential of the compounds was appraised by hemolytic assay. The results showed that some of the synthesized compounds exhibited marked activity. 相似文献
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Global atmospheric electrical parameters like atmospheric conductivity, air-earth current density, electric field, and atmospheric
potential have been estimated over different places of United States (US) assuming fair weather conditions. Results show that
atmospheric electrical conductivity and current density increase with height from sea level, while electric field remains
constant at all altitudes. The atmospheric potential, on the other hand, decreases in US orography. New best fit regression
lines between the atmospheric electrical parameters and height from sea level have been examined for US orography in both
clean and clear atmosphere. 相似文献
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The last two decades have witnessed the research activities in the area of coordination polymers (CPs), which are structurally diverse and functionally intriguing materials. In this endeavor, the most exploited ligand has been a structurally rigid N-donor compound having an innocent backbone (incapable of forming hydrogen bond) namely 4,4'-bipyridine. Much has been achieved by exploiting this wonder ligand in the area of CPs. However, the positional isomers such as 3,3'-bipyridine or 4,3'-bipyridine (which understandably induce diverse ligating topology as compared to their more symmetrical 4,4' counterpart) were not exploited in much detail presumably because of the difficulty in their synthetic accessibility. To get access to such N-donor ditopic ligands having diverse ligating topology, much efforts have been focused in the last decade or so to design such positional isomers of 4,4'-bipyridine having a non-innocent backbone (capable of forming hydrogen bond). The principal focus of such studies is to decipher the effect of diverse ligating topology and the non-innocent backbone of the ligands on the overall supramolecular structures and functions of the resultant CPs. This tutorial review aims at highlighting some of the developments of such structurally diverse and functionally intriguing CPs derived from N-donor ditopic ligands having a non-innocent backbone. 相似文献
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Raghavan Govindarajan Dhirendra Pratap Singh Adarsh Pratap Singh Madan Mohan Pandey Ajay Kumar Singh Rawat 《Chromatographia》2007,66(5-6):401-405
Heracleum candicans Wall. ex DC (Apiaceae) finds use as an aphrodisiac, nerve tonic and also in the treatment of skin diseases in the Indian
system of medicines and is reported to be rich in furocoumarins which are extensively used in pharmaceutical industry for
their photosensitizing activity on human skin. Thus a HPLC–PDA method has been developed for the selection of suitable solvent
for extraction and quantitative estimation of these furocoumarins viz. heraclenol, heraclenin, bergapten and psoralen in fruits
of H. candicans. The results indicate that heraclenol is found to be maximum in 30% aqueous methanolic extract (0.108%) while the maximum
concentration of heraclenin (anti-inflammatory principle) and bergapten (melanogenesis stimulation activity) was found in
the pure methanolic extract (0.386 and 0.281%, respectively). However psoralen (anti-psoriatric principle) was found in very
low concentration in all the extracts. Further validation of the method was done in view to demonstrate its selectivity, linearity,
precision, accuracy and robustness. The method thus developed can be applied in quality evaluation of H. candicans. 相似文献