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排序方式: 共有895条查询结果,搜索用时 15 毫秒
891.
892.
T. Vijayakumar I. Hubert Joe C. P. Reghunadhan Nair Mojca Jazbinsek V. S. Jayakumar 《Journal of Raman spectroscopy : JRS》2009,40(1):52-63
The optimized geometry and structural features of the most prospective electro‐optic crystal 4‐(N,N‐dimethylamino)‐N‐methyl‐4′‐toluene sulfonate (DAST), and the vibrational spectral investigations have been comprehensively described with the near infrared Fourier transform (NIR FT) Raman and Fourier transform infrared (FT‐IR) spectra supported by the density functional theoretical (DFT) computations to elucidate the contribution of vibrational modes to the linear electro‐optic (LEO) effect. Mulliken population analysis and natural bond orbital (NBO) analysis have also been carried out to analyze the effects of intramolecular charge transfer (ICT), intramolecular hydrogen bonding and hyperconjugative interactions on the geometries. The influence of CT interaction between the phenyl ring and the dimethylamino group of the nonlinear optical (NLO) chromophore on the endocyclic and exocyclic angles, and the electronic effects such as hyperconjugation and back‐donation on the methyl hydrogen atoms have been examined. The concurrent intense activation of Raman and IR activities of the effective conjugation vibrational coordinate, which significantly contributes to the LEO effect resulting from the strong electron–phonon (e/ph) coupling, has been analyzed in detail. The effects of frontier orbitals, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), transition of electron density (ED) transfer and the influence of planarity in the stilbazolium ring on the first hyperpolarizability are also discussed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
893.
Camilla Russo Dr. Matthew C. Leech Jamie M. Walsh Dr. Joe I. Higham Lisa Giannessi Emmanuelle Lambert Cyrille Kiaku Dr. Darren L. Poole Dr. Joseph Mason Dr. Charles A. I. Goodall Dr. Perry Devo Dr. Mariateresa Giustiniano Dr. Marco Radi Dr. Kevin Lam 《Angewandte Chemie (International ed. in English)》2023,62(38):e202309563
Hydrogenation reactions are staple transformations commonly used across scientific fields to synthesise pharmaceuticals, natural products, and various functional materials. However, the vast majority of these reactions require the use of a toxic and costly catalyst leading to unpractical, hazardous and often functionally limited conditions. Herein, we report a new, general, practical, efficient, mild and high-yielding hydrogen-free electrochemical method for the reduction of alkene, alkyne, nitro and azido groups. Finally, this method has been applied to deuterium labelling. 相似文献
894.
Safa Almadhi Joe Forth Laura Rodriguez-Arco Aroa Duro-Castano Ian Williams Lorena Ruiz-Pérez Giuseppe Battaglia 《Macromolecular bioscience》2023,23(8):2300068
A bottom-up approach to fabricating monodisperse, two-component polymersomes that possess phase-separated (“patchy”) chemical topology is presented. This approach is compared with already-existing top-down preparation methods for patchy polymer vesicles, such as film rehydration. These findings demonstrate a bottom-up, solvent-switch self-assembly approach that produces a high yield of nanoparticles of the target size, morphology, and surface topology for drug delivery applications, in this case patchy polymersomes of a diameter of ≈50 nm. In addition, an image processing algorithm to automatically calculate polymersome size distributions from transmission electron microscope images based on a series of pre-processing steps, image segmentation, and round object identification is presented. 相似文献
895.
Mathematical Programming - We consider the problem of provably finding a stationary point of a smooth function to be minimized on the variety of bounded-rank matrices. This turns out to be... 相似文献