According to information from China University of Science and Technology, Professor Du Pingwu's research group synthesized the first long conjugated chain segment of single chiral index single-walled carbon nanotubes in the world through precise molecular design. The results were recently published in the Journal of the American Chemical Society in the form of a cover article.
Carbon nanotubes can be considered as all-carbon-based tubular conjugated polymers containing only sp2 bonded atoms, but there is no research report on long conjugated polymers of carbon nanotube fragments with specific diameter. Pure carbon nanotube materials with single diameter and chirality have important application potential in the fields of nanotechnology and electronics, however, the synthesis of such carbon nanotubes is an important challenge in the fields of synthetic chemistry and material chemistry. The method of catalyst surface-mediated growth shows great potential in preparing carbon nanotubes, but the purity of nanotubes is always an insurmountable problem.
Based on the previous series of work on the synthesis of new structures and physical properties of carbon nanotubes, researchers skillfully introduced the dual-functional structure into the curved conjugated small molecule carbon ring. Subsequently, through the coupling reaction of nickel catalysis, the fragment realized the extension in one-dimensional direction, and constructed the long conjugated chain segment of single-walled carbon nanotubes with definite diameter, using gel permeation chromatography, characterization methods such as nuclear magnetic resonance, infrared and Raman Spectra confirmed that long conjugated polymers of carbon nanotubes were successfully synthesized. Using wide-angle Ray diffraction test, it is found that the polymer solid film has obvious diffraction ring and shows certain crystallization. Comparing the absorption, fluorescence and fluorescence attenuation curves of monomer and conjugated polymer, it is found that the photophysical properties of polymer are greatly improved due to the increase of their conjugation degree.
The long conjugated chain segment is the world's first conjugated polymer compound whose structure is close to armchair-type single-walled carbon nanotubes, realizing a new long conjugated structure of synthesizing single-walled carbon nanotubes with specific diameter, it provides corresponding conjugated polymer templates for the preparation of ultra-pure single-walled carbon nanotubes, and also provides important reference for the preparation and property research of single chiral carbon nanotubes constructed by solution method.
