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排序方式: 共有241条查询结果,搜索用时 15 毫秒
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Dr. Ashutosh Ghosh Dr. Sourav Kanti Seth Arnab Ghosh Pradip Pattanayak Dr. Arabinda Mallick Prof. Pradipta Purkayastha 《化学:亚洲杂志》2021,16(9):1157-1164
Picric acid (PA) at low concentration is a serious water pollutant. Alongside, aliphatic amines (AAs) add to the queue to pollute surface water. Plenty of reports are available to sense PA with an ultralow limit of detection (LOD). However, only a handful of works are testified to detect AAs. A new fluorescent donor-acceptor compound has been synthesized with inherent intramolecular charge transfer (ICT) character that enables selective and sensitive colorimetric quantitative detection of PA and AAs with low LODs in non-aqueous as well as aqueous solutions. The synthesized compound is based on a hemicyanine skeleton containing two pyridenylmethylamino groups at the donor and a benzothiazole moiety at the acceptor ends. The detailed mechanisms and reaction dynamics are explained spectroscopically along with computational support. The fluorescence property of the detecting compound changes due to protonation of its pyridinyl centers by PA leading to quenching of fluorescence and subsequently de-protonation by AAs to revive the signal. We have further designed logic circuits from the acquired optical responses by sequential interactions. 相似文献
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Chandra Shekhar Tiwari Praseetha Mathoor Illam S. N. R. Donthireddy Dr. Arnab Rit 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(67):16581-16600
In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas of scientific developments. Cyclometalation reactions result in the formation of stable metallacycles through the generation of metal-carbon covalent bonds by activating the unreactive Csp2-H or Csp3-H bonds. The extra stability gained by the formation of metallacycles enhances their applicability scopes especially in the area of homogeneous catalysis. In the recent research development in this area, NHC ligands (strong σ-donor and generally, weak π-acceptor) have been found to be one of the most suitable candidates for the intramolecular C−H activation process which leads to the cyclometalated species. The growth in the area of cyclometalation chemistry that started in the late 20th century is still continuing and in the past few decades, various examples of NHC derived transition metal-based cyclometalated complexes came into the picture. As covering all the reported literatures in this area (includes mainly late transition metals) will exceed the limits of minireview, we restricted ourselves to the recent (2015 – May 2021) examples of the most common Ru-, Rh-, and Ir-based CNHC^C cyclometalated complexes and their applications in various homogeneous catalytic conversions such as transfer hydrogenation, amidation, oxidation of alcohols, annulations, and so forth. 相似文献
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Supriyo Paul Krishna Kumar Mahendra K. Verma Daniele Carati Arnab K. De Vinayak Eswaran 《Pramana》2010,74(1):75-82
In this paper we investigate two-dimensional (2D) Rayleigh-Bénard convection using direct numerical simulation in Boussinesq
fluids with Prandtl number P = 6.8 confined between thermally conducting plates. We show through the simulation that in a small range of reduced Rayleigh
number r (770 < r < 890) the 2D rolls move chaotically in a direction normal to the roll axis. The lateral shift of the rolls may lead to a
global flow reversal of the convective motion. The chaotic travelling rolls are observed in simulations with free-slip as
well as no-slip boundary conditions on the velocity field. We show that the travelling rolls and the flow reversal are due
to an interplay between the real and imaginary parts of the critical modes. 相似文献
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