A hexafluoroisopropanol (HFIP)-catalyzed difluoroalkylation of propargylic alcohols with difluoroenoxysilanes to access structurally diverse tetrasubstituted difluoroalkyl allenes has been developed. This convenient procedure enables the rapid construction of highly functionalized multisubstituted fluorinated allenes in a mild and straightforward way. Furthermore, the synthetic potential of this methodology has been demonstrated by the facile synthesis of various structurally interesting fluorinecontaining molecules such as gem-difluorosubstituted dihydropyran, tetrasubstituted CF 2 H-allene, and multisubstituted fluorinated cyclopentanone derivatives.
How to furnish catalysts with switchable catalytic ability is a challenge in self‐controlled catalysis. This issue was addressed by constructing a unique polymer nanoreactor containing “mobility‐recalling” switchable domains that acted as a molecular switch for providing access to the encapsulated metal nanoparticles. This polymer reactor revealed poor reactivity at relatively low temperatures because of the “frozen” molecular chains in the switchable domains inhibiting the access of substrate to the encapsulated metal nanoparticles (i.e., catalytic “off” status). In contrast, the polymer reactor demonstrated significant reactivity at relatively high temperatures, resulting from the dramatically increased mobility of the molecular chains, which allowed access to the encapsulated nickel nanoparticles (i.e., catalytic “on” status). Switching between the catalytic off and on statuses could be repeated owing to the recallable mobility of molecular chains in the switchable domains. This protocol opens up the opportunity to develop smart nanoreactors for controlled chemical processes.
Transition metal co-catalysts exhibit considerable potential in photocatalytic water splitting process, but their limited activity and poor stability inhibit the extensive application, and therefore effective schemes are required to further...
As efficient cocatalysts in photocatalytic processes, transition metal phosphides are usually synthesized in harsh and tedious conditions. So to achieve their simple and controllable loading on photocatalyst surface is especially valuable.
Fluorescent carbon dots (CDs) are widely applied for the detection of heavy metal ions due to their nontoxicity, high sensitivity and stability. In this work, CDs were synthesized by a simple and green pyrolysis method without complicated postprocessing procedures and characterized by transmission electron microscope, X-ray diffraction, fourier transform infrared spectroscopy, UV-visible spectrophotometer and fluorescence spectroscopy. The CDs exhibited a relatively narrow size distribution of 3.5-8.6 nm with an average size of 6.1 nm and their surface was decorated with abundant functional groups such as hydroxy and amino groups. They exhibited a strong fluorescent peak at 468 nm with a quantum yield of 25% under 365 nm UV irradiation. The CDs exhibited a strong fluorescence response to 70 μM Cu 2 + with the sensitivity up to 77% due to the complexation between the amino groups decorated on the CD surface and the adsorbed copper ions. They also exhibited short response times of less than 1 min, high response selectivity and good stability.
Results and discussion
Characterization of CDsThe morphology of the as-prepared CDs was firstly observed by a TEM, as shown in figure 1 A). Some CDs exhibit nearly spherical structure and others exhibit irregular structure. The partially enlarged image of a CD exhibits distinct lattice structure with the lattice spacing of 0.29 nm, which corresponds to the (020) crystal surface. [30] The CDs exhibit a narrow [a] Dr.
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