RESUMO
A self-decoupled porphyrin with a tripodal anchor has been synthesized and deposited on Au(111) using different wet-chemistry methods. Nanoscale electroluminescence from single porphyrin molecules or aggregates on Au(111) has been realized by tunneling electron excitation. The molecular origin of the luminescence is established by the vibrationally resolved fluorescence spectra observed. The rigid tripodal anchor not only acts as a decoupling spacer but also controls the orientation of the molecule. Intense molecular electroluminescence can be obtained from the emission enhancement provided by a good coupling between the molecular transition dipole and the axial nanocavity plasmon. The unipolar performance of the electroluminescence from the designed tripodal molecule suggests that the porphyrin molecule is likely to be excited by the injection of hot electrons, and then the excited state decays radiatively through Franck-Condon π*-π transitions. These results open up a new route to generating electrically driven nanoscale light sources.
RESUMO
Radical reaction of [60]fullerene with phosphonates or phosphine oxide mediated by manganese(III) acetate dihydrate in chlorobenzene under three different conditions afforded three different types of phosphorylated fullerenes: singly bonded fullerene dimers 2, hydrophosphorylated fullerenes 3, and acetoxylated fullerene derivatives 4. In addition, interconversions among the three types of phosphorylated fullerene derivatives have also been investigated. A possible reaction mechanism was proposed to explain experimental results.
RESUMO
Radical reaction of [60]fullerene with phosphonate esters mediated by manganese(III) acetate in chlorobenzene afforded singly-bonded fullerene dimers, of which the individual meso and racemic isomers could be unexpectedly separated out for the first time.
RESUMO
Six new triterpenoid saponins of the ursane types were isolated from the MeOH extract of the leaves of Ilex oblonga. They were oblonganoside A (1), oblonganoside B (2), oblonganoside C (6), oblonganoside D (8), oblonganoside E (9), and oblonganoside F (10), together with three known triterpenoid saponins. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and compound 1 showed appreciable inhibitory activity against TMV replication with EC50 value 0.074 mM.
Assuntos
Ilex/química , Folhas de Planta/química , Saponinas/farmacologia , Vírus do Mosaico do Tabaco/efeitos dos fármacos , Triterpenos/farmacologia , Antivirais/química , Antivirais/farmacologia , Estrutura Molecular , Folhas de Planta/virologia , Saponinas/química , Nicotiana/virologia , Triterpenos/química , Replicação Viral/efeitos dos fármacosRESUMO
Ten triterpene saponins have been isolated from a MeOH extract of the leaves of Ilex oblonga. In their structures, six new triterpenoid saponins were named as oblonganosides H-M (2, 4, 5, and 8-10). All structures were elucidated on the basis of spectroscopic analysis. Among the triterpenoid saponins, three compounds (7, 8, and 10) showed obvious activities in inhibiting multiplication of the tobacco mosaic virus (TMV).