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81.
Palladium(II)‐Catalyzed meta‐CH Olefination: Constructing Multisubstituted Arenes through Homo‐Diolefination and Sequential Hetero‐Diolefination 下载免费PDF全文
Dr. Milan Bera Arun Maji Dr. Santosh K. Sahoo Prof. Debabrata Maiti 《Angewandte Chemie (International ed. in English)》2015,54(29):8515-8519
Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium‐catalyzed synthesis of divinylbenzenes by meta‐C? H olefination of sulfone‐based arenes. Successful sequential olefinations in a position‐selective manner provided a novel route for the synthesis of hetero‐dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5‐trialkenylated compounds can be generated upon successful removal of the directing group. 相似文献
82.
Sanchita Mondal Saikat Kumar Manna Kalipada Maiti Rajkishor Maji Syed Samim Ali Srimanta Manna 《Supramolecular chemistry》2017,29(8):616-626
A FRET-based chemosensor L containing donor phenanthroline and acceptor fluorescein moiety was designed, synthesised and characterised for the ratiometric fluorescent detection of Cu2+ in organo-aqueous solution. Probe L showed high selectivity and excellent sensitivity towards Cu2+ ions by exhibiting both colorimetric and fluorometric changes due to opening of the spirolactum ring of fluorescein upon complexation with Cu2+. In presence of Cu2+ ions, probe L formed L-Cu2+ complex in 1:1 stoichiometric fashion which is established on the basis of Job’s plot and mass spectroscopy. We also performed DFT computational studies to know the binding nature and coordination feature of the complex. Furthermore, fluorescence imaging studies revealed that probe L was cell permeable and could be used to detect intracellular Cu2+ in living cells. 相似文献
83.
Amitesh Maiti 《International journal of quantum chemistry》2014,114(3):163-175
With the negative environmental implications of the anthropogenic emission of greenhouse gases like CO2 having been scientifically established, emphasis is being placed on a concerted global effort to prevent such gases from reaching the atmosphere. Especially important are capture efforts at large point emission sources like fossil fuel power generation, natural gas processing, and various industrial plants. Given the importance and scale of such activities, it is a significant priority to optimize the capture process in terms of speed, energy requirements, and cost efficiency. For CO2 capture, in particular, multiple systems are being pursued both with near‐term retrofitting and medium‐ to long‐term designs in mind, including: (1) liquid solvents like amines, carbonates, and ionic liquids (ILs); (2) microporous sorbents like zeolites, activated carbon, and metal‐organic frameworks; (3) solid sorbents like metal‐oxides and ionic clays; and (4) polymeric and inorganic membrane separators. Each system is unique in its molecular‐level guest–host interactions, chemistry, heats of adsorption/desorption, and equilibrium thermodynamic and transport properties as a function of loading, temperature, and pressure. This opens up exciting opportunities for molecular modeling in the design and optimization of materials systems. Here, we offer a brief survey of molecular modeling applications in the field of carbon capture, with a few illustrative examples from our own work primarily involving amine solutions and ILs. Important molecular dynamics, Monte Carlo, and correlations‐based work in the literature relevant to CO2 capture in other systems are also discussed. © 2013 Wiley Periodicals, Inc. 相似文献
84.
Nagarwal RC Singh PN Kant S Maiti P Pandit JK 《Chemical & pharmaceutical bulletin》2011,59(2):272-278
The aim of this investigation was to develop 5-fluorouracil (5-FU) loaded chitosan nanoparticles (CH-DNPs) for ophthalmic delivery. CH-DNPs were fabricated by ionotropic gelation mechanism using chitosan (CH) and a polyanion (TPP). The nanoparticles were smooth and spherical, confirmed by scanning electron microscopy (SEM) and atomic force microscope (AFM). CH/TPP mass ratio and TPP significantly changed the particles size morphology and encapsulation efficiency. The nanoparticles size ranged from approximately 114 to 192 nm and had a positive zeta potential (30±4 mV). The encapsulation efficiency, loading capacity and recovery of DNPs were 8.12-34.32%, 3.14-15.24% and 24.22 to 67% respectively. Physical characterization was done by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). No interaction was observed in between drug and polymer and crystallinity of drug was not changed in drug loaded nanoparticles. In-vitro release study of DNPs showed diffusion controlled release. Bioavailability study of batch CS9 was studied in rabbit eye and compare to 5-FU solution. 5-FU level was significantly higher in aqueous humor of rabbit eye. Ocular tolerance was studied in the eye of New Zealand rabbits and tested formulation was non-irritant with no sign of inflammation. 相似文献
85.
Maiti KK Samanta A Vendrell M Soh KS Olivo M Chang YT 《Chemical communications (Cambridge, England)》2011,47(12):3514-3516
SERS nanotags have been prepared to accomplish the multiplex detection of cancer cells. Herein we evaluated the adequacy of lipoic acid-containing cyanine derivatives (Cy3LA and Cy5LA) to function as multiplex partners with a triphenylmethine Raman reporter (B2LA) under a single excitation wavelength. SERS experiments enabled the multiplex recognition of two different cancer cells with antibody-conjugated nanotags that were derivatized with optimized cyanine and triphenylmethine reporters. 相似文献
86.
Maiti D 《Chemical communications (Cambridge, England)》2011,47(29):8340-8342
An orthogonal set of Cu-catalysts for the selective mono-arylation of alkyl aryl diols using aryl iodides is presented. Picolinic acid ligated copper catalyst provided phenol O-arylation only, while alkyl aryl ethers are generated by ligand-free copper catalyst in the presence of 2 equivalents NaOt-Bu. 相似文献
87.
Ekta Shandilya Basundhara Dasgupta Dr. Subhabrata Maiti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(29):7831-7836
Understanding the fundamental facts behind dynamicity of catalytic processes has been a longstanding quest across disciplines. Herein, we report self-assembly of catalytically active gold nanorods that can be regulated by tuning its reactivity towards a proton transfer reaction at different pH. Unlike substrate-induced templating and co-operativity, the enhanced aggregation rate is due to alteration of catalytic surface charge only during reactivity as negatively charged transition state of reactant (5-nitrobenzisoxazole) is formed on positively charged nanorod while undergoing a concerted E2-pathway. Herein, enhanced diffusivity during catalytic processes might also act as an additional contributing factor. Furthermore, we have also shown that nanosized hydrophobic cavities of clustered nanorods can also efficiently accelerate the rate of an aromatic nucleophilic substitution reaction, which also demonstrates a catalytic phenomenon that can lead to cascading of other reactions where substrates and products of the starting reactions are not directly involved. 相似文献
88.
Sumon Basak Subhabrata Dutta Prof. Dr. Debabrata Maiti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(41):10533-10557
The skeletal presence of 1,3-azoles in a variety of bioactive natural products, pharmacophores, and organic materials demands the derivatization of such heteroarenes regioselectively. Plenty of cross-coupling as well as cyclocondensation reactions have been performed to build up these skeletons but remained commercially unrealizable. A couple of severe drawbacks are faced by these traditional protocols that require a more straightforward strategy to obviate them. Transition metal-catalyzed C−H functionalization has emerged as a superior alternative in that context. 1,3-Azoles and their benzo counterparts have been extensively functionalized exploiting both noble and earth-abundant transition metals. Lately, C-2 functionalization have gained much traction due to the ease of attaining high regioselectivity and installation of synthetically manipulative functionalities. This critical review presents a bird‘s eye view of all major C-2 functionalization of (benz)azoles catalyzed by a diverse set of metals performed over the past 15 years. 相似文献
89.
Oil-water interface in the two-dimensional Larson type of model 总被引:2,自引:0,他引:2
Prabal K. Maiti 《Physics letters. A》1997,230(5-6):369-372
90.
Multi-item inventory models with two storage facility and bulk release pattern are developed with linearly time dependent
demand in a finite time horizon under crisp, stochastic and fuzzy-stochastic environments. Here different inventory parameters—holding
costs, ordering costs, purchase costs, etc.—are assumed as probabilistic or fuzzy in nature. In particular cases stochastic
and crisp models are derived. Models are formulated as profit maximization principle and three different approaches are proposed
for solution. In the first approach, fuzzy extension principle is used to find membership function of the objective function
and then it’s Graded Mean Integration Value (GMIV) for different optimistic levels are taken as equivalent stochastic objectives.
Then the stochastic model is transformed to a constraint multi-objective programming problem using Stochastic Non-linear Programming
(SNLP) technique. The multi-objective problems are transferred to single objective problems using Interactive Fuzzy Satisfising
(IFS) technique. Finally, a Region Reducing Genetic Algorithm (RRGA) based on entropy has been developed and implemented to
solve the single objective problems. In the second approach, the above GMIV (which is stochastic in nature) is optimized with
some degree of probability and using SNLP technique model is transferred to an equivalent single objective crisp problem and
solved using RRGA. In the third approach, objective function is optimized with some degree of possibility/necessity and following
this approach model is transformed to an equivalent constrained stochastic programming problem. Then it is transformed to
an equivalent single objective crisp problem using SNLP technique and solved via RRGA. The models are illustrated with some
numerical examples and some sensitivity analyses have been presented. 相似文献