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91.
92.
Ghulam Mohmad Subhajit Sarkar Ashmita Biswas Kingshuk Roy Dr. Ramendra Sundar Dey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(55):12664-12673
The design and synthesis of metal-free catalysts with superior electrocatalytic activity, high durability, low cost, and under mild conditions is extremely desirable but remains challenging. To address this problem, a polymer-assisted electrochemical exfoliation technique of graphite in the presence of an aqueous acidic medium is reported. This simple, cost-effective, and mass-scale production approach could open the possibility for the synthesis of high-quality nitrogen-doped graphene–polypyrrole (NG-PPy). The NG-PPy catalyst displays an improved half wave potential (E1/2=0.77 V) in alkaline medium compared with G-PPy (E1/2=0.66 V). Most importantly, this catalyst demonstrates excellent stability with high methanol tolerance, and it outperforms the commercial Pt/C catalyst and other previously reported metal-free catalysts. The content of graphitic nitrogen atoms is the key factor for the enhancement of electrocatalytic activity towards oxygen reduction reactions (ORR). Interestingly, the NG-PPy catalyst can be used as a cathode material in a zinc–air battery, which demonstrates a higher peak power density (59 mW cm−2) than G-PPy (36.6 mW cm−2), highlighting the importance of the low-cost material synthesis approach towards the development of metal-free efficient ORR catalysts for fuel cell and metal–air battery applications. Remarkably, the polymer-assisted electrophoretic exfoliation of graphite with a high yield (≈88 wt %) of few-layer graphene flakes could pave the way towards the mass production of high-quality graphene for a variety of applications. 相似文献
93.
Subhajit Laha Dr. Darsi Rambabu Dr. Sohini Bhattacharyya Prof. Tapas Kumar Maji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(64):14671-14678
Various hierarchical micro/mesoporous MOFs based on {[Al(μ-OH)(1,4-NDC)]⋅H2O} ( MOF1 ) with tunable porosities (pore volume and surface area) have been synthesized by assembling AlIII and 1,4-NDC (1,4-naphthalenedicarboxylate) under microwave irradiation by varying water/ethanol solvent ratio. Water/ethanol mixture has played a crucial role in the mesopore generation in MOF1M25 , MOF1M50 , and MOF1M75 , which is achieved by in situ formation of water/ethanol clusters. By adjusting the ratio of water/ethanol, the particle size, surface area and micro/mesopore volume fraction of the MOFs are controlled. Furthermore, reaction time plays a critical role in mesopore formation as realized by varying reaction time for the MOF with 50 % ethanol ( MOF1M50 ). Additionally, hierarchical MOF ( MOF1M50 ) has been used as a template for the stabilization of MAPbBr3 (MA=methylammonium) perovskite quantum dots (PQDs). MAPbBr3 PQDs are grown inside MOF1M50 , where mesopores control the size of PQDs which leads to quantum confinement. 相似文献
94.
95.
Sirsendu Das Adhikary Ambarish Mondal Hemanta K. Kisan Christopher W. Bielawski Joydev Dinda 《应用有机金属化学》2020,34(2):e5335
A series of silver(I) and gold(I) carbene complexes of the type [M(L)(2,2′-bipyridine)][PF6] (L = 1-benzyl-3-(2-pyridylmethyl)benzimidazolylidene; M = Ag ( 1 ); M = Au ( 3 )) and [M(L)(carbazole)] (M = Ag ( 2 ); M = Au ( 4 )) were synthesized and analyzed using a range of spectroscopic and crystallographic techniques. Inspection of the solid-state structures of 1 , 2 and 4 revealed a number of intermolecular noncovalent interactions. In the solid-state structure adopted by 1 , π–π and Ag–Ag interactions directed the complexes to orient in a head-to-tail fashion. The photophysical properties were found to be influenced by the ancillary ligands in solution as well as in the solid-state. Calculations were performed to support the aforementioned structural and optoelectronic assignments. 相似文献
96.
Dinda Soumitra Sarkar Koushik Panda Bikash Kumar Pramanik Kausikisankar Ganguly Sanjib 《Transition Metal Chemistry》2022,47(1):31-38
Transition Metal Chemistry - By using a multifunctional diarylazooxime ligand LNOH 1, incorporating electron deficient azo chromophore in conjunction with a pendant π-electron-rich naphthyl... 相似文献
97.
Mitchell RH Bohne C Wang Y Bandyopadhyay S Wozniak CB 《The Journal of organic chemistry》2006,71(1):327-336
[structure: see text] The synthesis of the multistate photochromic switch 3 is described. This switch contains three dihydropyrene (DHP) units in the most conjugated fully closed form 3-c,c,c. The thermally stable form has the central DHP unit open and is 3-c,o,c. NMR and laser flash photolysis experiments were used to characterize the multiple states in the photoswitching of 3 by visible and UV light. Three of the possible five isomeric states of 3-c,o,c were observed. Irradiation of 3-c,o,c by visible light led to the formation of 3-o,o,o via the isomer 3-c,o,o as an intermediate, which were observed by NMR. Irradiation by UV light led to the formation of 3-c,c,c, which decays with a lifetime of 7.5 ms. 相似文献
98.
An anthrylidene derivative of arjunolic acid could immobilize varieties of organic solvents at low concentrations in the presence of an electron-deficient guest. Gelation in the presence of picric acid in organic solvents could be observed visually with concomitant color change. Electron micrographs of the xerogels showed a fibrous structure having fibers of submicron diameters. [structure: see text]. 相似文献
99.
100.
Dr. Shivani Sharma Subhajit Dutta Dr. Gourab K. Dam Prof. Sujit K. Ghosh 《化学:亚洲杂志》2021,16(18):2569-2587
Neutral nitrogen donor (N-donor) ligand-based MOFs, with their enticing features inclusive of facile synthesis, labile metal-ligand bond, framework flexibility, atomic level tunability renders them appealing in molecular recognition-based studies. Intriguingly, the flexibility in such systems (owing to weaker metal-nitrogen bonds) promote maximization of host-analyte interactions, which is critical for the manifestation of a signaling response. Such host-analyte interactions can be tapped by discerning any change in the physical properties associated with the system, such as optical, fluorometric, chemiresistive, magnetic, dielectric constant, mass. This minireview presents a brief discussion on the various types of signal transduction pathways unveiled hitherto using neutral N-donor ligand-based MOFs and the fundamental insight into the signal‘s origin. Moreover, an elaborate compilation of the recent examples in this field has been presented. Also, the untapped prospects have been highlighted, which may serve as a beacon to drive future research. 相似文献