Conjugated Microporous Polymers Based on Tetraphenylethylene for Gas Adsorption

Abstract

Conjugated microporous polymers (CMPs) are attracting increasing attention due to their potential applications in areas such as gas adsorption, separation, heterogeneous catalysis and photoelectron. A series of CMPs based on tetra- phenylethylene has been synthesized via Pd-catalyzed Sonogashira-Hagihara coupling reaction. During polymerization, all of the polymer networks precipitated from solution as yellow powders that are totally insoluble in common organic solvents tested because of their highly crosslinked structures. Thermogravimetric analysis indicated that all of the polymer networks are thermally stable up to 400 in nitrogen atmosphere. Th ℃ e high physicochemical and thermal stability could be attributed to the rigid nature of these aromatic polymers, composed solely of strong carbon-carbon and carbon-hydrogen bonds. The absence of the C≡H stretching peaked at around 3280 cm -1 and the C—Br stretching peaked at around 500 cm -1 in the FT-IR spectra for the polymer networks demonstrated that most of the ethynyl and bromine functional groups in the starting materials have been consumed by coupling reaction. Powder X-ray diffraction measurements revealed that all of the polymer networks are amorphous in nature. It was found that the homo-coupled polymer network of TPE-CMP1 from 1,1,2,2-tetrakis(4-ethynylphenyl)ethene shows the highest Brunauer-Emmet-Teller specific surface area up to 1096 m 2 •g -1