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31.
We report heteroleptic ruthenium complexes of terpyridine (tpy) ligands with directly linked carboxylic acid anchors. These complexes feature methyl or methoxy-substituted 4′−Phtpy as donor ligands. We prepared these heteroleptic complexes from the ruthenium (II) precursor via a milder route to preclude the homoleptic complex formation. The donor−acceptor arrangement of tpy ligands in these ruthenium complexes renders visible light absorption giving metal and ligand-to-ligand charge transfer excitations at c.a. 490 nm. We evaluate the effect of the tpy donor substituents on the light-harvesting ability in Dye-Sensitized Solar Cells (DSSCs) and compare their photosensitizing ability with heteroleptic complexes bearing phenyl spacer at the acceptor end. Further, scrutinizing their photovoltaic performance, we studied their electron transfer kinetics in DSSCs using electrochemical impedance spectroscopy. This paper presents the structure-photosensitization relationship of these heteroleptic ruthenium complexes through a combined experimental and computational approach.  相似文献   
32.
Organoboron derivatives of biologically potent β‐enamino esters of the type [Where R = CH3(1a), C2H5 (1b), C3H7(1c) and C (CH3)3 (1d)] have been prepared by the reactions of β‐enamino esters and Phenyl boronic acid [PhB (OH)2] in 1:2 molar ratio in refluxing tetrahydrofuran (THF). All these derivatives have been characterized by physico‐chemical properties, elemental analyses and molecular weight measurements. The structures of these compounds have been proposed on the basis of IR, 1H, 13C, 11B NMR spectral data and GC‐mass spectrometry. Phenyl boronic acid, β‐enamino esters and their respective phenylboronates derivatives have been screened for the antibmicrobial activities against pathogenic bacteria (B. subtilis and E. coli) and fungi (A. niger and P. peniculosum) to access their growth inhibiting potential. In addition to this, antiandrogenic effect of Ligand, LaH2 and its boron derivative (1a) has also been tested in male albino rats.  相似文献   
33.
Fractional precipitation techniques have been utilized to separate the lower valent and parent forms of56Mn in permanganate targets and an attempt is made to study a few aspects of chemical stabilization of recoil56Mn in permanganates. Ammonium permanganate, recoil behaviour of which has not been studied previously, is chosen as one of the targets along with the potassium permanganate for initial retention and also for isothermal annealing.56Mn initial retentions of about 12% and about 4% are obtained for potassium and ammonium permanganate, respectively, by activation from a Ra–Be neutron source. A usual trend for KMnO4 and the reduction of recoil fragments by ammonium ions in NH4MnO4 are seen through the isothermal annealing study.  相似文献   
34.
A method for the determination of lead is described using thiol-functionalized gold nanoparticle. The detection method is based on the prevention of thiol-induced aggregation of gold nanoparticles by lead. Among six thiols, e.g., 4-mercapto-1-butanol, meso-2, 3-dimercaptosuccinic acid, mercaptosuccinic acid, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol, 1-propanethiol, four (4-mercapto-1-butanol, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol and 1-propanethiol) induced the aggregation of the gold nanoparticles which was measured by the change in absorbance at 520 and 650?nm. Prior incubation of the gold nanoparticles with lead decreased the 4-(methylthio)-1-butanol-induced aggregation of gold nanoparticles in a dose-dependent manner. A linear inverse relationship between the logarithmic concentration of lead and the ratio of absorbance at 650 to 520 was noted. The method has a dynamic range from 10?nM to 100?µM. However, metals such as mercury and chromium were more effective in comparison with lead in preventing the 4-methylthio-1-butanol-induced aggregation of gold nanoparticles. The method can be used for assessing the heavy metal load in water samples.  相似文献   
35.
Manganese(II) complexes having the general composition Mn(L)2X2 (where L = 3‐bromoacetophenone semicarbazone, 3‐bromoacetophenone thiosemicarbazone, 1‐tetralone semicarbazone, 1‐tetralone thiosemicarbazone, flavanone semicarbazone or flavanone thiosemicarbazone and X = Cl? or ½SO42?) were synthesized. All the complexes were characterized using elemental analyses, molar conductance and magnetic moment measurements, and mass, 1H NMR, infrared, electron paramagnetic resonance and electronic spectral studies. The molar conductance of the complexes in dimethylsulfoxide lies in the range 10–20 Ω?1 cm2 mol?1 indicating their non‐electrolytic nature. All the complexes show magnetic moments corresponding to five unpaired electrons. The possible geometries of the complexes were assigned on the basis of electron paramagnetic resonance, electronic and infrared spectral studies. Some of the synthesized ligands and their complexes were screened for their antifungal activities against fungi Macrophomina phaseolina, Botrytis cinerea and Phoma glomerata using the food poison technique and their antibacterial activities against Xanthomonas campestris pv. campestris and Ralstonia solanacearum using the paper disc diffusion method. They showed appreciable activities.  相似文献   
36.
The discovery of a new L-valine promoted facile and versatile green synthesis of diversified 2-amino-3-cyano-4H-pyrans using a one pot multicomponent-tandem reaction of aromatic aldehydes, malononitrile, and diverse electron-rich enolizable carbonyl compounds is described. To the best of our knowledge this is the first report on the use of native L-valine as a catalyst in organic synthesis. Environmental friendly, mild reaction conditions, use of easily available inexpensive starting materials, short reaction time, excellent yields, high atom economy, and recyclability of organocatalyst are the major advantages of the disclosed protocol.  相似文献   
37.
Pursuing our recent interest regarding antimicrobial and anti-inflammatory activities of coumarin derivatives, we have synthesized a series of coumarin-linked pyridopyrimidinones by using Baylis Hillman adduct in aqueous condition with high purity. Pyrido[1,2-a]pyrimidin-2-ones are important class of heterocyclic compounds because of their use in medicinal and agro chemistry as active agents. All these newly synthesized compounds were evaluated for their antimicrobial and anti-inflammatory activity. Coumarin pyridopyrimidinones showed excellent anti-inflammatory activity against both MMP-2 and MMP-9 gelatinase zymography, whereas considerable good activity against Gram-positive and Gram-negative bacterial strains; however, antifungal activity observed in these series is more or less inactive. The active compounds of these series would be promising structural templates for the development of novel and more efficient anti-inflammatory agent.  相似文献   
38.
Reducing p-nitrophenol (PNP) to p-aminophenol is an industrially relevant synthesis. Nevertheless, only a few heterogeneous catalysts have been evaluated for the reduction of PNP by glycerol. Appropriate quantum computational studies can screen potential catalysts for this crucial green reaction. The present research investigates the catalytic activities of Pd@Ag and Ni@Ag core-shell nanogeometries toward PNP reduction by glycerol through density functional theory (DFT) calculations. The central atom of a geometry-optimized 13-atom Ag cluster was replaced by Pd and Ni atoms to create the core-shell morphologies. The interaction energies of PNP and glycerol with each of the (metal/bimetallic) clusters were evaluated by DFT calculations to find the best PNP and glycerol molecule orientation with the respective bimetallic cluster. Electrostatic potential surface and natural bond orbital analyses were performed to study the charge distribution and transfer between atomic orbitals. The frequencies of vibrational modes in isolated PNP/glycerol structures were compared to those when these molecules were in the presence of the different metal clusters to infer the effect of the interactions. All performed analyses indicated improved catalytic activity toward PNP reduction by glycerol upon Ni-doping of the Ag13 cluster.  相似文献   
39.
A green and facile novel procedure has been developed for the synthesis of Cu2O nanoparticles within a very short reaction time using banana pulp extract as a reducing agent. The synthesized nanoparticles are well characterized by SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope) and powder XRD (X-ray Diffraction) methods. An environmental benign and highly efficient protocol for the ipso-hydroxylation of aryl and hetero arylboronic acids using bio-fabricated Cu2O nanoparticles as a catalyst and aqueous H2O2 as an oxidant has also been developed. The main advantages of this protocol are the base free reaction condition, reusable and heterogeneous catalytic system, and short reaction time with excellent yields.  相似文献   
40.
MicroRNAs (miRNAs) are important nonprotein-coding genes involved in almost all biological processes during biotic and abiotic stresses in plants. To investigate the miRNA-mediated plant response to drought stress, two drought-tolerant (C-306 and NI-5439) and two drought-sensitive (HUW-468 and WL-711) wheat genotypes were exposed to 25 % PEG 6000 for 1, 12 and 24 h. Temporal expression patterns of 12 drought-responsive miRNAs and their corresponding nine targets were monitored by quantitative real-time PCR (qRT-PCR). The results showed differential expression of miRNAs and their targets with varying degree of upregulation and downregulation in drought-sensitive genotypes. Likewise, in drought-tolerant wheat genotypes, maximum accumulation of miR393a and miR397a was observed at 1 h of stress. In addition, nearly perfect negative correlation was observed in four miRNA and target pairs (miR164-NAC, miR168a-AGO, miR398-SOD and miR159a-MYB) across all the temporal period studied which could be a major player during drought response in wheat. We, for the first time, validated the presence of miR529a and miR1029 in wheat. These findings gives a clue for temporal and variety-specific differential regulation of miRNAs and their targets in wheat in response to osmotic shock and could help in defining the potential roles of miRNAs in plant adaptation to osmotic stress in future.  相似文献   
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