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981.
982.
Naphthobipyrrole‐Derived Sapphyrins: Rational Synthesis,Characterization, Nonlinear Optical Properties,and Excited‐State Dynamics
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Dr. Tridib Sarma Puliparambil Thilakan Anusha Ashok Pabbathi Dr. Soma Venugopal Rao Dr. Pradeepta K. Panda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15561-15570
Two new free‐base β‐octa and hexaalkyl naphthobipyrrole‐derived sapphyrins are reported along with various salts thereof. One of them has substituents at all of its β positions, whereas the pyrrole unit opposite to the bipyrrolic moiety is unsubstituted in the other. The effect of bipyrrole fusion on the structure of sapphyrins was explored. Interestingly, an unprecedented sandwiched supramolecular aqua‐bridged free‐base sapphyrin dimer was also characterized in the solid state. Further, the effect of anions on the third‐order nonlinear optical properties of these sapphyrins were explored in the salt form, along with their detailed excited‐state dynamics by both degenerate and nondegenerate pump–probe studies. 相似文献
983.
984.
Vesztergom Soma Barankai Norbert Kovács Noémi Ujvári Mária Siegenthaler Hans Broekmann Peter Láng Győző G. 《Journal of Solid State Electrochemistry》2016,20(11):3165-3177
Journal of Solid State Electrochemistry - The subject of this paper is electrical cross-talk, an interference between the current/voltage characteristics of the two working electrodes in... 相似文献
985.
Sukanta Bhattacharyya 《合成通讯》2013,43(24):4647-4654
A mild procedure for the reductive deoxygenation of α-ferrocenyl aldehydes and ketones is reported using sodium borohydride and zinc chloride. The present method allows synthesis of alkylferrocenes containing functionalized tethers and is adaptable to large-scale preparations. 相似文献
986.
987.
Subhajit Chakraborty Somen Nandi Kankan Bhattacharyya Saptarshi Mukherjee 《Chemphyschem》2020,21(5):406-414
Fluorescence dynamics of gold nanoclusters (Au9 and Au25) are studied in the complex and crowded environment of a triblock co-polymer (F127) hydrogel and inside cervical cancer cell, HeLa. In the hydrogel, spherical micelles of F127 remain immobilized with a hydrophobic core (PPO) and a hydrophilic corona (PEO) region. The fluorescence anisotropy decay suggests that the timescale of rotational relaxation in the hydrogel is similar to that in bulk water (viscosity ∼1 cP). From fluorescence correlation spectroscopy (FCS) it is inferred that the local viscosity in the hydrogel is 12 cP for Au9 and 18 cP for Au23. These results indicate that gold nanoclusters (AuNCs) localize in the corona region of the hydrogel. Evidently, frictions against rotation and translation are different inside the gel. It is suggested that rotation of the AuNCs senses the immediate water-like “void” region while translation motion involves in-and-out movement of the AuNCs at the periphery of the gel. Finally, the gold nanoclusters are used for cell imaging and estimation of intracellular viscosity of HeLa cells. 相似文献
988.
The two most promising approaches for preparing solid contacts (SCs) for polymeric membrane based ion‐selective electrodes (ISEs) are based on the use of large surface areas conducting materials with high capacitance (e. g., various carbon nanotubes) and redox active materials (e. g. conducting polymers). While many of the essential requirements for the potential stability of SCISEs were addressed, the E0 reproducibility and its predictability, that would enable single use of such electrodes without calibration is still a challenge, i. e., the fabrication of electrodes with sufficiently close E0 and slope values to enable the characterization of large fabrication batches through the calibration of only a small number of electrodes. The most generic solution seems to be the adjustment of the E0 potential by polarization prior to the application of the ion‐selective membrane. This approach proved to be successful in case of conducting polymer‐based solid contacts, but has to be still explored for capacitive solid contact based ISEs, which is the purpose of this paper. We have chosen a well‐established highly lipophilic multi‐walled carbon nanotube (MWCNT), i. e. octadecane modified MWCNT (OD‐MWCNT), that is investigated in the comparative context of a similarly lipophilic conducting polymer solid contact (a perfluorinated alkanoate side chain functionalized poly(3,4‐ethylenedioxythiophene)). While, the OD‐MWCNT based SCISEs had inherently small standard deviation of their E0 values (less than 5 mV) this could be further improved by external polarization and short circuiting the SCISEs. 相似文献
989.
Alloying in an Intercalation Host: Metal Titanium Niobates as Anodes for Rechargeable Alkali‐Ion Batteries
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Suman Das Dr. Diptikanta Swain Dr. Rafael B. Araujo Dr. Songxin Shi Prof. Rajeev Ahuja Prof. Tayur N. Guru Row Prof. Aninda J. Bhattacharyya 《化学:亚洲杂志》2018,13(3):299-310
We discuss here a unique flexible non‐carbonaceous layered host, namely, metal titanium niobates (M‐Ti‐niobate, M: Al3+, Pb2+, Sb3+, Ba2+, Mg2+), which can synergistically store both lithium ions and sodium ions via a simultaneous intercalation and alloying mechanisms. M‐Ti‐niobate is formed by ion exchange of the K+ ions, which are specifically located inside galleries between the layers formed by edge and corner sharing TiO6 and NbO6 octahedral units in the sol‐gel synthesized potassium titanium niobate (KTiNbO5). Drastic volume changes (approximately 300–400 %) typically associated with an alloying mechanism of storage are completely tackled chemically by the unique chemical composition and structure of the M‐Ti‐niobates. The free space between the adjustable Ti/Nb octahedral layers easily accommodates the volume changes. Due to the presence of an optimum amount of multivalent alloying metal ions (50–75 % of total K+) in the M‐Ti‐niobate, an efficient alloying reaction takes place directly with ions and completely eliminates any form of mechanical degradation of the electroactive particles. The M‐Ti‐niobate can be cycled over a wide voltage range (as low as 0.01 V) and displays remarkably stable Li+ and Na+ ion cyclability (>2 Li+/Na+ per formula unit) for widely varying current densities over few hundreds to thousands of successive cycles. The simultaneous intercalation and alloying storage mechanisms is also studied within the density functional theory (DFT) framework. DFT expectedly shows a very small variation in the volume of Al‐titanium niobate following lithium alloying. Moreover, the theoretical investigations also conclusively support the occurrence of the alloying process of Li ions with the Al ions along with the intercalation process during discharge. The M‐Ti‐niobates studied here demonstrate a paradigm shift in chemical design of electrodes and will pave the way for the development of a multitude of improved electrodes for different battery chemistries. 相似文献
990.