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291.
Z Yin AY Tam KM Wong CH Tao B Li CT Poon L Wu VW Yam 《Dalton transactions (Cambridge, England : 2003)》2012,41(37):11340-11350
A series of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivatives containing ion- and pH-sensory units have been successfully designed and synthesized. One of the compounds was structurally characterized by X-ray crystallography. Owing to the presence of an ICT absorption band, one of the compounds was found to show pronounced solvatochromic behavior in different organic solvents. Their emission energies in various solvents show a linear dependence on the Lippert solvent parameter. The cation-binding properties of the complexes with different metal ions (alkali metal, alkaline earth metal and transition metal ions) have been studied using UV-vis and emission spectroscopies. A 1?:?1 complexation to metal ions (Li(+), Na(+), Mg(2+), Ba(2+), Zn(2+), Cd(2+)) was found for the compound with one azacrown moiety in acetonitrile while another one with two azacrown moieties was shown to form 1?:?2 complexes with Zn(2+) and Mg(2+) cations. Their stability constants have been determined by both UV-vis and emission spectrophotometric methods. By introducing triarylborane moieties into the meso position and the 2-position of the BODIPY skeleton, different electronic absorption spectral changes together with an emission diminution were observed in response to fluoride ions. Ditopic binding study of 5, which was functionalized with both azacrown and triarylborane moieties, showed emission enhancement in the presence of Mg(2+) and F(-). These findings suggest that these BODIPY derivatives are capable of serving as versatile colorimetric and luminescence probes for pH, cations and F(-). 相似文献
292.
2-Benzyloxy-1-methylpyridinium triflate (1) is a stable, neutral organic salt that converts alcohols into benzyl ethers upon warming. The synthesis and reactivity of 1 are described herein. Benzylation of a wide range of alcohols occurs in good to excellent yield. 相似文献
293.
Maclaughlin C.; Pedersen H.; Poon Y. S.; Salamon S. 《Journal London Mathematical Society》2006,73(1):173-193
We develop deformation theory for abelian invariant complexstructures on a nilmanifold, and prove that in this case theinvariance property is preserved by the Kuranishi process. Apurely algebraic condition characterizes the deformations leadingagain to abelian structures, and we prove that such deformationsare unobstructed. Various examples illustrate the resultingtheory, and the behavior possible in three complex dimensions. 相似文献
294.
Dyads of a N-confused porphyrin (NCP) moiety covalently linked to a porphyrin free-base (H2P) or a zinc(II) porphyrinate (ZnP) moiety via a flexible alkyl chain of variable length have been synthesized. Photoluminescence study demonstrated an efficient excitation energy transfer from H2P/ZnP moiety to the NCP moiety. Measurement of the near-IR emission of singlet oxygen produced by these dyads via photosensitization showed that the NCP-ZnP dyads (ФΔ = (0.61-0.65) ± 0.13) were better 1O2 generators than the NCP-P dyads (ФΔ = (0.36-0.41) ± 0.08). 相似文献
295.
Poon Clarice Keriven Nicolas Peyré Gabriel 《Foundations of Computational Mathematics》2023,23(1):241-327
Foundations of Computational Mathematics - Compressed sensing (CS) ensures the recovery of sparse vectors from a number of randomized measurements proportional to their sparsity. The initial theory... 相似文献