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911.
Efficient White‐Light Generation from Ionically Self‐Assembled Triply‐Fluorescent Organic Nanoparticles 下载免费PDF全文
Dr. Susmita Das Tanay Debnath Amrita Basu Dr. Deepanwita Ghosh Prof. Abhijit Kumar Das Dr. Gary A. Baker Prof. Amitava Patra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8855-8863
Low cost, simple, and environmentally friendly strategies for white‐light generation which do not require rare‐earth phosphors or other toxic or elementally scare species remain an essentially unmet challenge. Progress in the area of all‐organic approaches is highly sought, single molecular systems remaining a particular challenge. Taking inspiration from the designer nature of ionic‐liquid chemistry, we now introduce a new strategy toward white‐light emission based on the facile generation of nanoparticles comprising three different fluorophores assembled in a well‐defined stoichiometry purely through electrostatic interactions. The building blocks consist of the fluorophores aminopyrene, fluorescein, and rhodamine 6G which represent blue, green, and red‐emitting species, respectively. Spherical nanoparticles 16(±5) nm in size were prepared which display bright white‐light emission with high fluorescence quantum efficiency (26 %) and color coordinate at (0.29, 0.38) which lie in close proximity to pure white light (0.33, 0.33). It is noteworthy that this same fluorophore mixture in free solution yields only blue emission. Density functional theory calculations reveal H‐bond and ground‐state proton transfer mediated absolute non‐parallel orientation of the constituent units which result in frustrated energy transfer, giving rise to emission from the individual centers and concomitant white‐light emission. 相似文献
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Gary E. Martin R. Thomas Williamson Peter G. Dormer Wolfgang Bermel 《Magnetic resonance in chemistry : MRC》2012,50(8):563-568
ADEQUATE experiments provide an alternative to the more commonly employed GHMBC experiment for the establishment of long‐range heteronuclear connectivities. The 1,1‐ADEQUATE experiment allows the unequivocal identification of both protonated and non‐protonated carbon resonances adjacent to a protonated carbon. The 1,n‐ADEQUATE experiment establishes correlations via an initial 1JCH heteronuclear transfer followed by an nJCC out‐and‐back transfer, most typically, via three carbon–carbon bonds. Hence, the 1,n‐ADEQUATE experiment allows the equivalent of 4JCH heteronuclear correlations to be probed when they are not observed in a GHMBC spectrum. Aside from the lower sensitivity of the 1,n‐ADEQUATE experiment relative to GHMBC experiments, the interpretation of the former is also complicated by the ‘leakage’ of 1JCC correlations into the spectrum that must be identified. A method for the inversion of 1JCC correlations to facilitate the interpretation of 1,n‐ADEQUATE spectra is presented that allows a single experiment to be performed to access 1JCC and nJCC correlation information. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Peterman Dean R. Zarzana Christopher A. Tillotson Richard D. McDowell Rocklan G. Rae Cathy Groenewold Gary S. Law Jack D. 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(2):855-860
Journal of Radioanalytical and Nuclear Chemistry - Separating the minor actinide elements (americium and curium) from the fission product lanthanides is an important step in closing the nuclear... 相似文献
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Stochastic Stability of Lyapunov Exponents and Oseledets Splittings for Semi‐invertible Matrix Cocycles 下载免费PDF全文
We establish (i) stability of Lyapunov exponents and (ii) convergence in probability of Oseledets spaces for semi‐invertible matrix cocycles subjected to small random perturbations. The first part extends results of Ledrappier and Young to the semi‐invertible setting. The second part relies on the study of evolution of subspaces in the Grassmannian; the analysis developed here is based on higher‐dimensional Möbius transformations and is likely to be of wider interest. © 2015 Wiley Periodicals, Inc. 相似文献
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Jagadish B Brickert-Albrecht GL Nichol GS Mash EA Raghunand N 《Tetrahedron letters》2011,52(17):2058-2061
1,4,7-Tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane is widely used as an intermediate in the preparation of medically important DO3A and DOTA metal chelators. Despite its commercial availability and importance, the literature describing the preparation and properties of the free base is limited and sometimes unclear. We present herein an efficient synthesis of the hydrobromide salt of 1,4,7-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane, characterize this compound spectroscopically and by X-ray crystallographic analysis, describe its simple conversion to the corresponding free base, characterize this compound spectroscopically and by X-ray crystallographic analysis, and make observations on the reactivity of this interesting and useful compound. 相似文献
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Gary L. Hagnauer 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(1):385-408
Polydichlorophosphazene (NPC12)X is unique as a synthetic precursor for poly(organo)phosphazenes [1–6] and presents special problems in polymerization studies because of branching, crosslinking, and cyclization reactions and in characterization due to the polymer's hydrolytic instability. This paper reviews the literature and discusses problem areas and recent advances relating to polydichlorophosphazene polymerization. Melt, solution, and irradiation polymerization reactions and mechanisms are discussed. Previously unpublished results are presented, and current research efforts and areas for future investigation are considered. 相似文献