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991.
Samanta D Faure N Rondelez F Sarkar A 《Chemical communications (Cambridge, England)》2003,(10):1186-1187
A variety of groups like a Fischer carbene complex, an N-hydroxysuccinimide or a ferrocene derivative have been grafted by ruthenium-catalyzed cross-metathesis reaction with terminal alkene groups on monolayer-protected gold clusters as a mild and convenient strategy to anchor functional molecules. 相似文献
992.
993.
This study focuses on the development of a new electric field responsive graphene oxide (GO) nanoparticle system for on-demand drug delivery. Today, GO is an attractive option adopted in various biological applications for its exclusive features such as flexibility, conductiveness, cost-effectiveness, and external stimuli-responsive nature. It is usual to utilize multiple drugs in cancer treatment. This kind of therapy has lesser side-effects, drug resistance, and is more effective than utilizing only one drug. This study aims to determine low-voltage-controlled dual drug (aspirin and doxorubicin) release from GO surface. Here, we have demonstrated how to control the drug release rate remotely with a handy mobile phone, with zero passive release at idle time. In addition, the study focused to estimate the synergism of aspirin with doxorubicin in the release mechanism from GO in the presence of external voltage, using the spectroscopic method. Moreover, we observed aspirin- and doxorubicin-induced synergistic antitumor activity in MDA-MB 231 (breast cancer cell) in vitro. Thus, our study presents a noble combination of aspirin and doxorubicin that could be utilized for remotely controlled on-demand drug delivery for triple negative breast cancer treatment, using GO as a carrier. 相似文献
994.
Degradation of organic pollutants in wastewater is a common subject of discussion under advanced oxidation process. To detect the degradation of colourless organic pollutants conventional analytical techniques are available but their sophistication makes it difficult to pursue in all form of chemical laboratories. In the present study it was found that during degradation of Dichlorvos using diethylene triamine pent acetic acid (DTPA) stabilized nano zero valent iron (nZVI), COD removal and ac conductivity change has been done simultaneously. In this degradation study the heterogeneous Fenton type oxidation method was employed and an LCR circuit (which contains inductor, capacitor and resistor) was used to measure the ac conductivity. This study aims to find out a correlation between ac conductivity and COD removal using simple response surface methodology (RSM) so that the degradation of colourless pollutants can be estimated easily and also to identify the best processing parameters to optimise Dichlorvos degradation. It was found that COD removal in most of all cases, was more than 60% when the change in final ac conductivity more than 600% with respect to initial value. All of the experimental results were in good accord with the projected outcome. 相似文献
995.
In this paper, we consider a modular extension to the game of Nim, which we call m-Modular Nim, and explore its optimal strategy. In m-Modular Nim, a player can either make a standard Nim move or remove a multiple of m tokens in total. We develop a winning strategy for all m with 2 heaps and for odd m with any number of heaps. 相似文献
996.
Jessica Stubbe Nicols I. Neuman Ross McLellan Michael G. Sommer Maite Nßler Julia Beerhues Robert E. Mulvey Biprajit Sarkar 《Angewandte Chemie (International ed. in English)》2021,60(1):499-506
We present herein anionic borate‐based bi‐mesoionic carbene compounds of the 1,2,3‐triazol‐4‐ylidene type that undergo C?N isomerization reactions. The isomerized compounds are excellent ligands for CoII centers. Strong agostic interactions with the “C?H”‐groups of the cyclohexyl substituents result in an unusual low‐spin square planar CoII complex, which is unreactive towards external substrates. Such agostic interactions are absent in the complex with phenyl substituents on the borate backbone. This complex displays a high‐spin tetrahedral CoII center, which is reactive towards external substrates including dioxygen. To the best of our knowledge, this is also the first investigation of agostic interactions through single‐crystal EPR spectroscopy. We conclusively show here that the structure and properties of these CoII complexes can be strongly influenced through interactions in the secondary coordination sphere. Additionally, we unravel a unique ligand rearrangement for these classes of anionic mesoionic carbene‐based ligands. 相似文献
997.
We have demonstrated the efficient synthesis of Pd(II)-based 2D mesoporous covalent organic framework (COF) along with a small amount of Pd(0), which is characterized by different characterization tools. These studies suggest that this material with low bandgap energy (Eg) of 1.73 eV can exhibit great photocatalytic activity toward CO2 fixation reaction. Therefore, we have applied the Pd(II)-loaded COF as a new and effective photocatalyst for the preparation of oxazolidinone through the chemical fixation of CO2. The reaction takes place in green solvent (H2O) in absence of any base and under the sunlight at atmospheric pressure of CO2 without using any cocatalyst. The reaction does not happen in the dark. In this context, we showed that a turnover number (TON) of 3.392 × 103 can be achieved using the catalytic cycle under sunlight. The light dependency of the reaction is also checked by a control experiment via light modulation between light on and off. Furthermore, the catalyst shows efficient reusability for multiple reaction cycles, and also the heterogeneity test of the material suggests minimal active metal leaching during the catalysis reaction cycles. These results for the photocatalytic synthesis of oxazolidinone by CO2 incorporation over COF under sunlight open a new environment-friendly green pathway for the formation of oxazolidinones. 相似文献
998.
Metallogels Derived from Silver Coordination Polymers of C3‐Symmetric Tris(pyridylamide) Tripodal Ligands: Synthesis of Ag Nanoparticles and Catalysis 下载免费PDF全文
Mithun Paul Koushik Sarkar Prof. Parthasarathi Dastidar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):255-268
By applying a recently developed crystal engineering rationale, four C3 symmetric tris(pyridylamide) ligands namely 1,3,5‐tris(nicotinamidomethyl)‐2,4,6‐triethylbenzene, 1,3,5‐tris(isonicotinamidomethyl)‐2,4,6‐triethylbenzene, 1,3,5‐tris(nicotinamidomethyl)‐2,4,6‐trimethylbenzene, and 1,3,5‐tris(isonicotinamidomethyl)‐2,4,6‐trimethylbenzene, which contain potential hydrogen‐bonding sites, were designed and synthesized for generating AgI coordination polymers and coordination‐polymer‐based gels. The coordination polymers thus obtained were characterized by single‐crystal X‐ray diffraction. The silver metallogels were characterized by transmission electron microscopy (TEM) and dynamic rheology. Upon exposure to visible light, these silver metallogels produced silver nanoparticles (AgNPs), which were characterized by TEM, powder X‐ray diffraction, energy dispersive X‐ray and X‐ray photoelectron spectroscopy. These NPs were found to be effectively catalyzed the reduction of 4‐nitrophenolate to 4‐aminophenolate without the use of any exogenous reducing agent. 相似文献
999.
Mesoporous Silica MCM‐41 Supported N‐Heterocyclic Carbene‐Pd Complex for Heck and Sonogashira Coupling Reactions 下载免费PDF全文
Heterocyclic carbene‐Pd complex was anchored onto the mesoporous silica MCM‐41 which exhibits high catalytic activity in Heck reaction under phosphine free reaction conditions for the reaction of iodo/bromoarenes with olefinic compounds such as butyl acrylate, isopropyl acrylate and styrene. This catalytic system also showed high activity for Sonogashira coupling reaction of various aryl halides under copper, phosphine and solvent‐free reaction conditions. The air and thermally stable catalyst were reused several times without significant loss of its activity. High efficiency of the catalyst along with its recycling ability and the rather low Pd‐loading demonstrated in both Heck and Sonogashira coupling reactions are the merits of the presented catalyst system. 相似文献
1000.
Ursula Pachmayr Fabian Nitsche Dr. Hubertus Luetkens Sirko Kamusella Felix Brückner Dr. Rajib Sarkar Prof. Dr. Hans‐Henning Klauss Prof. Dr. Dirk Johrendt 《Angewandte Chemie (International ed. in English)》2015,54(1):293-297
Superconducting [(Li1?xFex)OH](Fe1?yLiy)Se (x≈0.2, y≈0.08) was synthesized by hydrothermal methods and characterized by single‐crystal and powder X‐ray diffraction. The structure contains alternating layers of anti‐PbO type (Fe1?yLiy)Se and (Li1?xFex)OH. Electrical resistivity and magnetic susceptibility measurements reveal superconductivity at 43 K. An anomaly in the diamagnetic shielding indicates ferromagnetic ordering near 10 K while superconductivity is retained. The ferromagnetism is from the iron atoms in the (Li1?xFex)OH layer. Isothermal magnetization measurements confirm the superposition of ferromagnetic and superconducting hysteresis. The internal ferromagnetic field is larger than the lower, but smaller than the upper critical field of the superconductor. The formation of a spontaneous vortex phase where both orders coexist is supported by 57Fe‐Mössbauer spectra, 7Li‐NMR spectra, and μSR experiments. 相似文献