The gas-phase acidities of chloroanilino-radicals have been measured, and have been combined with the electron affinities of chlorophenylnitrenes to determine the N–H bond dissociation energy of chloroanilino-radicals and the enthalpies of formation for the triplet, singlet, and radical anion states of the isomeric nitrenes. There is little difference found between the bond dissociation energies in the radicals and those in the corresponding anilines, indicating little interaction between the unpaired electrons in the chlorophenylnitrene, as expected. The values obtained are in good agreement with the values obtained from the theoretical calculations.
Nonaromatic, cross‐conjugated, and highly twisted luminogens consisting of acylated succinimides demonstrate aggregation‐induced emission characteristics along with tunable multicolor photoluminescence and afterglows in their single crystals. Effective through‐space conjugation among different moieties bearing n/π electrons promote the spin–orbit coupling and intersystem crossing and lead to diverse emissive clusters with concurrently rigidified conformations, thus allowing readily tunable emissions. Derived from it, the proof‐of‐concept application for advanced anti‐counterfeiting is illustrated. These results should spur the rational design of novel nonaromatic AIEgens, and moreover advance understandings of the non‐traditional intrinsic luminescence and the origin of tunable multicolor afterglows. 相似文献
Afterglow–magnetic nanoparticles (NPs) offer enormous potential for bioimaging applications, as they can be manipulated by a magnetic field, as well as emitting light after irradiation with an excitation source, thus distinguishing themselves from fluorescent living cells. In this work, a novel double core–shell strategy is presented, uniting co-precipitation with combustion synthesis routes to combine an Fe3O4 magnetic core (≈15 nm) with an afterglow SrAl2O4:Eu2+,Dy3+ outer coat (≈10 nm), and applying a SiO2 protective middle layer (≈16 nm) to reduce the luminescence quenching caused by the Fe core ions. The resulting Fe3O4@SiO2@SrAl2O4:Eu2+,Dy3+ NPs emit green light attributed to the 4f65d1→4f7(8S7/2) transition of Eu2+ under UV radiation and for a few seconds afterwards. This bifunctional nanocomposite can potentially be applied for the detection and separation of cells or diagnostically relevant molecules. 相似文献
Hot lava is a viscous fluid that, driven by gravity, moves along the Earth's surface. Intuitively, one attributes constructional properties to lava–it accumulates in volcanic landforms, compound lava fields and, in the end, entire mountains. On the other hand, there are also examples of the erosive power of lava: on Earth and especially on other planets in the Solar System, there exist channels incised by flowing lava. The origins of these erosive features have long been debated among volcanologists and planetologists. The dominant paradigm is thermal erosion, although it leaves many questions open. After the 2001 eruption on Mount Etna we found a lava channel whose features cannot be explained in the frame of thermal erosion. On the basis of our observations, we have developed a model for mechanical erosion that explains the main field observations, and opens alternative ways to describe erosion by flowing lava. 相似文献
