Ellegaardholmgaard1438

Mechanical interlocking of a nanohoop fluorophore and a reactive thread couples the benefits of a reaction-based probe with a sterically congested active site for enhanced selectivity. Advantageously, the thread design uses dual function stoppers that act as both a quencher and a trigger for sensing. In progress toward expanding this approach to biologically relevant analytes, this system is used to demonstrate steric differentiation and provide a selective turn-on fluorescent response with size selectivity for HS- rather than larger thiolates.A novel, practical, highly efficient, and transition metal free nitrogen insertion reaction for the synthesis of 2,3-disubstituted quinazolinone derivatives was developed. Diverse functionalized 3-indolinone-2-carboxylates and nitrosoarenes with a wide range of substituted nitrosobenzenes, nitrosopyridines, dibenzofuranyl, or dibenzothienyl nitroso compounds worked smoothly to give 2,3-disubstituted quinazolinone derivatives in good to excellent yields (69-98%). A gram-scale reaction was achieved, and an afloqualone analogue was synthesized under the mild reaction conditions.We herein report an unprecedented photoinduced cyclization/defluorination domino process of N-allylbromodifluoroacetamide with cyclic secondary amines. Consequently, a wide array of valuable 3-fluoro-1,5-dihydro-2H-pyrrol-2-ones were facilely prepared from readily available starting materials under mild conditions. Preliminary mechanistic investigations suggest that a radical chain propagation and amine-promoted defluorination pathway are presumably involved in this transformation.Plasmonic structures confine electromagnetic energy at the nanoscale, resulting in local, inhomogeneous, controllable heating, but reading out the temperature using optical techniques poses a difficult challenge. Here, we report on the optical thermometry of individual gold nanorod trimers that exhibit multiple wavelength-dependent plasmon modes resulting in measurably different local temperature distributions. Specifically, we demonstrate how photothermal microscopy encodes different wavelength-dependent temperature profiles in the asymmetry of the photothermal image point spread function. These asymmetries are interpreted through companion numerical simulations to reveal how thermal gradients within the trimer can be controlled by exciting its hybridized plasmon modes. We also find that plasmon modes that are optically dark can be excited by focused laser beam illumination, providing another route to modify thermal profiles beyond wide-field illumination. Taken together these findings demonstrate an all-optical thermometry technique to actively create and measure nanoscale thermal gradients below the diffraction limit.The development of selective catalytic reactions that utilize easily available reagents for the efficient synthesis of alcohols is a long-standing goal of chemical research. Here an intriguing strategy for the chemodivergent copper-catalyzed hydroxymethylation of alkynes with formic acid and hydrosilane has been developed. By simply tuning the amount of formic acid and reaction temperature, distinct one-carbon-extended primary alcohols, that is, allylic alcohols and β-branched alkyl alcohols, were produced with high levels of Z/E-, regio-, and enantioselectivity.Forming olivine-structured Li(Mn,Fe)PO4 solid solution is theoretically a feasible way to improve the energy density of the solid solutions for lithium ion batteries. However, the Jahn-Teller active Mn3+ in the solid solution restricts their energy density and rate performance. Here, as demonstrated by operando X-ray diffraction, we show that equimolar LiMn0.5Fe0.5PO4 solid solution nanocrystals undergo a single-phase transition during the whole (de)lithiation process, with a feature of zero lithium miscibility gap, which endows the nanocrystals with excellent electrochemical properties. Specifically, the energy density of LiMn0.5Fe0.5PO4 reaches 625 Wh kg-1, which is 16% higher than that of LiFePO4. Moreover, the high-performance LiMn0.5Fe0.5PO4 nanocrystals are prepared by a microwave-assisted hydrothermal synthesis in pure water.The transition-metal-catalyzed allylation reaction is an efficient strategy for the construction of new carbon-carbon bonds alongside allyl or homoallylic functionalization. Herein we describe a Ni-catalyzed reductive allylation of α-chloroboronates to efficiently render the corresponding homoallylic boronates, which could be readily converted into valuable homoallylic alcohols or amines or 1,4-diboronates. This reaction features a broad substrate scope with good functional group compatibility that is complementary to the existing methods for the preparation of homoallylic boronates.Lead halide perovskite nanocrystals, whether formed by their own nucleation and growth or by ion diffusion into the lattice of others, are still under investigation. Moreover, beyond isotropic nanocrystals, fabricating anisotropic perovskite nanocrystals by design has remained difficult. Exploring the lattice of orthorhombic-phase Cs2ZnBr4 with the complete replacement of Zn tetrahedra by Pb octahedra, dimension-tunable anisotropic nanocrystals of CsPbBr3 are reported. This B-site ion introduction led to CsPbBr3 nanorods having [100] as major axis, in contrast with all reports on rods/wires where the lengths were along the [001] direction. selleck kinase inhibitor This was possible by using derivatives of α-bromo ketones, which helped in tuning the shape of Cs2ZnBr4 and also the facets of transformed CsPbBr3. While similar experiments are extended to orthorhombic Cs2HgBr4, standard nanorods with [001] as the major axis were observed. From these results, it is further concluded that anisotropic perovskite nanocrystals might not follow any specific rules for directional growth and instead might depend on the structure of the parent lattice.Understanding the detailed process of spontaneous formation of intrinsic defects and their ability to tune the electronic structures in functional materials has become a key prerequisite for their technological applications. Here, by using in situ scanning tunneling microscopy, we report the observation of one-dimensional Frenkel chain defects on the cleaved CsBi4Te6 surface due to the migration of Te atoms for the first time. Further scanning tunneling spectroscopy measurements clearly revealed a self-electron doping effect of the Frenkel chain defects, which could directly affect their thermoelectric and superconducting properties. The unique one-dimensional Frenkel tellurium atomic chain defect and its doping effect on the electronic structure observed here not only shed light on tuning the electric properties of a series of tellurides but also possess profound implications for enriching the microscopic details of defect chemistry and materials science.