科研之友
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摘要
The two terminal pyridyl nitrogen atoms of 2,7-bis(4-pyridyl)fluorene (1) were coordinated to Pd(II) ions to give self-assembled, multilayer films using the layer-by-layer (LbL) method. The films were prepared by alternately dipping the substrate, pre-coated with a polyethyleneimine layer, in aqueous solutions of PdCl2 and ethanol solutions of 1. The resulting films were characterized using UV-visible absorption spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy, scanning electron microscopy (SEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). UV-visible spectra and SEM images show almost uniform growth of the film in a near ideal LbL manner. AFM images show that nanostructured aggregates of Pd(II) complexes form on the surface. With an increase in the number of Pd(II)/1 bilayers, more particulate aggregates are distributed on the surface. When released from the substrate, the Pd(II) complex nanostructure shows high catalytic activity for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions. The catalyst loading is as low as 9.1 x 10(-3) mol% Pd, as measured using ICP-AES, and high turnover numbers of up to 1.08 x 10(4) are obtained.
- 出版日期2015-12
- 单位宁波大学
