نتایج جستجو برای: boron nitride crown ethers
تعداد نتایج: 53535 فیلتر نتایج به سال:
The discovery of the crown ethers stemmed from efforts to control the catalytic activity of vanadium and copper by complexation with multidentate ligands. The first crown ether, 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene, was obtained in 0.4% yield during an attempt to prepare a phenolic ligand from catechol and bis(2-chloroethyl)ether. This compound, which complexed with...
The effects of edge chemistry on the relative stability and electronic properties of zigzag boron nitride nanoribbons (ZBNNRs) are investigated. Among all functional groups considered, fully hydroxylated ZBNNRs are found to be the most energetically stable. When an in-plane external electric field is applied perpendicular to the axis of both hydrogenated and hydroxylated ZBNNRs, a spin-polarize...
A bolaamphiphilic low-molecular-weight gelator based on crown ether, which could self-assemble into organogels and hydrogels, was prepared. The contribution of each part of the structure to the gelation property was investigated by designing a series of analogues. A simple framework (crown ether-hydrophobic linkage-ammonium salt) was proposed.
We present the temperature-dependent carrier mobility of atomically thin MoS2 field-effect transistors on crystalline hexagonal boron nitride (h-BN) and SiO2 substrates. Our results reveal distinct weak temperature dependence of the MoS2 devices on h-BN substrates. The room temperature mobility enhancement and reduced interface trap density of the single and bilayer MoS2 devices on h-BN substra...
Wetting of a single hexagonal boron nitride sheet by liquid water has been investigated by molecular dynamics simulations within a temperature range between 278 and 373 K. The wetting temperature was found to be ~310 K, while the onset of prewetting happens around the much higher temperature of 354 K. The static (hydrogen-bond populations, density profiles, energy per molecule) and dynamic (dif...
The threefold symmetry of planar boron nitride (BN), the III-V analog to graphene, prohibits an electric polarization in its ground state, but this symmetry is broken when the sheet is wrapped to form a BN nanotube. We show that this leads to an electric polarization along the nanotube axis which is controlled by the quantum mechanical boundary conditions on its electronic states around the tub...
The symmetry properties of atomically thin boron nitride (BN) monolayers endow them with piezoelectric properties, whereas the bulk parent crystal of stacked BN layers is not piezoelectric. This suggests potential for unusual electromechanical properties in the few layer regime. In this work, we explore this regime and discover that a bilayer consisting of two BN monolayers exhibits a strong me...
After nitrogen, fluorine is probably the next most favorite hetero-atom for incorporation into small molecules in life science-oriented research. This review focuses on a particular fluorinated substituent, the trifluoromethoxy group, which is finding increased utility as a substituent in bioactives, but it is still perhaps the least well understood fluorine substituent in currency. The present...
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