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排序方式: 共有322条查询结果,搜索用时 15 毫秒
1.
Dr. Sudhir Kumar Keshri Dr. Waka Nakanishi Dr. Atsuro Takai Prof. Dr. Tomoya Ishizuka Prof. Dr. Takahiko Kojima Prof. Dr. Masayuki Takeuchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13288-13294
The design and synthesis of a tweezer-shaped naphthalenediimide (NDI)–anthracene conjugate ( 2NDI ) are reported. In the structure of the closed form (πNDI ⋅⋅⋅ πNDI stack) of 2NDI , which was elucidated by single-crystal XRD, the existence of C−H ⋅⋅⋅ O hydrogen bonding involving the nearest carbonyl oxygen atom of an NDI unit was suggested. The tunability of πNDI ⋅⋅⋅ πNDI interactions was studied by means of UV/Vis absorption, fluorescence and NMR spectroscopy and molecular modelling. This revealed that the πNDI ⋅⋅⋅ πNDI interactions in 2NDI affect the absorption and emission properties depending on the temperature. Furthermore, in polar solvents, 2NDI prefers the stronger πNDI ⋅⋅⋅ πNDI stack, whereas the πNDI ⋅⋅⋅ πNDI interaction is diminished in nonpolar solvents. Importantly, the conformational variations of 2NDI can be reversibly switched by variation in temperature, and this suggests potential application for fluorogenic molecular switches upon temperature changes. 相似文献
2.
Hélène Beucher Dr. Sudhir Kumar Dr. Roopender Kumar Dr. Estíbaliz Merino Wei-Hsu Hu Gerrit Stemmler Sergio Cuesta-Galisteo Dr. Jorge A. González Léonard Bezinge Dr. Jakub Jagielski Dr. Chih-Jen Shih Prof. Dr. Cristina Nevado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17604-17612
Efficient OLED devices have been fabricated using organometallic complexes of platinum group metals. Still, the high material cost and low stability represent central challenges for their application in commercial display technologies. Based on its innate stability, gold(III) complexes are emerging as promising candidates for high-performance OLEDs. Here, a series of alkynyl-, N-heterocyclic carbene (NHC)- and aryl-gold(III) complexes stabilized by a κ3-(N^C^C) template have been prepared and their photophysical properties have been characterized in detail. These compounds exhibit good photoluminescence quantum efficiency (ηPL) of up to 33 %. The PL emission can be tuned from sky-blue to yellowish green colors by variations on both the ancillary ligands as well as on the pincer template. Further, solution-processable OLED devices based on some of these complexes display remarkable emissive properties (ηCE 46.6 cd.A−1 and ηext 14.0 %), thus showcasing the potential of these motifs for the low-cost fabrication of display and illumination technologies. 相似文献
3.
Rathore Vikas Tiwari Budhi Sagar Nema Sudhir Kumar 《Plasma Chemistry and Plasma Processing》2022,42(1):109-129
Plasma Chemistry and Plasma Processing - The present study has been carried to investigate the interaction and effect of plasma activated water (PAW) on pea seeds. PAW is produced with the... 相似文献
4.
Anjana Prasad Nambiar Probal Nag Ruth Mariam Ipe Dr. Sivaranjana Reddy Vennapusa Dr. Sabapathi Gokulnath 《Angewandte Chemie (International ed. in English)》2023,62(30):e202306566
Herein, we report the synthesis of anthracene-containing twisted cyclo[2]dipyrrin 1 by utilizing a non-planar building block, 1,5-dipyrrylanthracene (1,5-DPA). The non-planar nature of the macrocycle enhanced the solubility and helped in structural characterization. Macrocycle 1 adopts a twisted ‘figure of eight’ conformation stabilized by strong intramolecular H-bonding interactions and exists as a pair of helical enantiomers, as revealed by X-ray crystallographic analysis. More importantly, the sterically locked structure enabled facile optical resolution using chiral HPLC. The (P,P) and (M,M) enantiomers show moderate chiroptical properties, such as absorption dissymmetry factors |gabs| in the order of 10−3, and luminescence dissymmetry factors |glum| of 3.8×10−3 and 2.9×10−3 at 702 nm, respectively. 相似文献
5.
Surekha S. Jogdand Abhishek Das Akshay Dhayagude Sudhir Kapoor Satyawati S. Joshi 《先进技术聚合物》2015,26(9):1114-1122
Polymeric materials have been found to be ideal candidates for the synthesis of organic–inorganic nanomaterials. We have obtained Co3O4‐decorated graphene oxide (GO) nanocomposites by a simple polymer combustion method. Polyvinyl alcohol (PVA) of two different molecular weights, 14,000 and 125,000, was used for the synthesis. The pristine sample was annealed at 300, 500, and 800°C. PVA has played an important role in the formation of GO and Co3O4 nanoparticles. Synthesized Co3O4–GO nanocomposites were characterized by X‐ray diffraction, Fourier transform infrared, Raman, electron paramagnetic resonance, transmission electron microscopy, and vibrating sample magnetometry. Reflection peaks at 12° and 37° in an X‐ray study confirm the formation of Co3O4–GO. Raman study validates the presence of GO in nanocomposites of Co3O4–GO. Room temperature ferromagnetism was observed in all annealed samples. The highest coercivity of 462 G was observed for 300°C annealed samples as compared with bulk Co3O4. On the basis of the results obtained, a mechanism of formation is proposed. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
Prebiotic Oligosaccharides: Special Focus on Fructooligosaccharides,Its Biosynthesis and Bioactivity
Sudhir P. Singh Jyoti Singh Jadaun Lokesh K. Narnoliya Ashok Pandey 《Applied biochemistry and biotechnology》2017,181(2):613-626
MicroRNAs (miRNAs) are important nonprotein-coding genes involved in almost all biological processes during biotic and abiotic stresses in plants. To investigate the miRNA-mediated plant response to drought stress, two drought-tolerant (C-306 and NI-5439) and two drought-sensitive (HUW-468 and WL-711) wheat genotypes were exposed to 25 % PEG 6000 for 1, 12 and 24 h. Temporal expression patterns of 12 drought-responsive miRNAs and their corresponding nine targets were monitored by quantitative real-time PCR (qRT-PCR). The results showed differential expression of miRNAs and their targets with varying degree of upregulation and downregulation in drought-sensitive genotypes. Likewise, in drought-tolerant wheat genotypes, maximum accumulation of miR393a and miR397a was observed at 1 h of stress. In addition, nearly perfect negative correlation was observed in four miRNA and target pairs (miR164-NAC, miR168a-AGO, miR398-SOD and miR159a-MYB) across all the temporal period studied which could be a major player during drought response in wheat. We, for the first time, validated the presence of miR529a and miR1029 in wheat. These findings gives a clue for temporal and variety-specific differential regulation of miRNAs and their targets in wheat in response to osmotic shock and could help in defining the potential roles of miRNAs in plant adaptation to osmotic stress in future. 相似文献
7.
Dr. Romaric Gérardy Dr. Anirudh M. K. Nambiar Travis Hart Prajwal T. Mahesh Prof. Dr. Klavs F. Jensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202201385
The implementation of self-optimizing flow reactors has been mostly limited to model reactions or known synthesis routes. In this work, a self-optimizing flow photochemistry platform is used to develop an original synthesis of the bioactive fragment of Salbutamol and derivatives. The key photochemical steps for the construction of the aryl vicinyl amino alcohol moiety consist of a C−C bond forming reaction followed by an unprecedented, high yielding (>80 %), benzylic oxidative cyclization. 相似文献
8.
9.
Sudhir Kumar Keshri Atsuro Takai Tomoya Ishizuka Takahiko Kojima Masayuki Takeuchi 《Angewandte Chemie (International ed. in English)》2020,59(13):5254-5258
The design and synthesis of an enantiomeric pair of 1,8‐diethynylanthracene‐bridged naphthalenediimide (NDI)‐based cyclophanes ( Cyclo‐NDI s) are reported. Each enantiomer of Cyclo‐NDI exhibits a circularly polarized luminescence signal with a relatively large luminescence dissymmetry factor (glum=±8×10?3). We have further investigated the modulation of through‐space electronic communication between co‐facially oriented NDIs in a discrete Cyclo‐NDI with changes in the temperature. Tuning of the electronic communication results from the conformational transformation of monomer‐ versus dimer‐like features of Cyclo‐NDI , as confirmed by UV/Vis, fluorescence, circular dichroic, and NMR spectroscopic analysis. The temperature‐dependent optical response in the Cyclo‐NDI through the conformational transformation could be utilized as a highly sensitive and reversible optical thermometer in a wide temperature range (100 to ?80 °C). 相似文献