p-Phenyleneethynylene-based comb-like oligomers: the synthesis and self-assembling property
摘要:
This paper describes the self-assembling property of three series of p-phenyleneethynylene based comb-like oligomers, which carry multiple peripheral side chains of different polarity. The new oligomers are prepared readily through the formation of the hydrazone bonds from the corresponding aldehyde and gallic acid-derived benzohydrazides. In polar solvents such as methanol and ethanol, the oligomers that bear n-decyl or 2-(2-(dioctylamino)-2-oxoethyl-amino)-2-oxoethoxyl unit (DOAOE) segments as the side chains are revealed to form vesicular structures, while the oligomers carrying hydrophilic oligo(ethyleneglycol) side chains do not. The structures of the vesicles are evidenced by SEM, AFM, TEM, and dye-encapsulation experiments. UV-vis absorption spectroscopic experiments suggest that the vesicles are generated through the stacking of the conjugated backbones, which is promoted by the solvophobic interaction of the peripheral side chains. (C) 2012 Elsevier Ltd. All rights reserved.
Carbene Bridging C-H Activation: Facile Isocoumarin Synthesis Through Palladium-Catalyzed Reaction of 2-Pseudohalobenzaldehydes with Aryl Diazoesters
作者:Chao Yan、Yinghua Yu、Bo Peng、Xueliang Huang
DOI:10.1002/ejoc.201901738
日期:2020.2.14
A strategy based on carbene bridging C–H activation is described. The bridging arm is generated via migratory insertion of a palladium carbene intermediate. Through this distinct pathway, a variety of isocoumarins could be prepared in a modular manner.
Tricyclic ringsystems possessing a dibenzo structure joined to a seven‐membered heterocyclicring frequently show important biological activities. However, a modular approach to these molecules based on efficient intermolecular reaction of readily available chemicals is lacking. Herein, an unprecedented palladium‐catalyzed formal [4+3] annulation for modular construction of these tricyclic systems is described