A Carbocationic Triarylmethane‐Based Porous Covalent Organic Network

• Published in: Chemistry : a European journal 2021-02, Vol.27 (7), p.2342-2347
• Main Authors: Freitas, Sunny K. S., Oliveira, Felipe L., Santos, Thiago C., Hisse, Danilo, Merlini, Claudia, Ronconi, Célia M., Esteves, Pierre M.
• Format: Article
• Language: English
• Subjects: carbocation; Carbon dioxide; Chemistry; covalent organic network; dye; Electrical conductivity; Electrical resistivity; Pore size; Porosity; porous materials; Thermal stability; Triarylmethane
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202003554

A thermally stable carbocationic covalent organic network (CON), named RIO‐70 was prepared from pararosaniline hydrochloride, an inexpensive dye, and triformylphloroglucinol in solvothermal conditions. This nanoporous organic material has shown a specific surface area of 990 m2 g−1 and pore size of 10.3 Å. The material has CO2 uptake of 2.14 mmol g−1 (0.5 bar), 2.7 mmol g−1 (1 bar), and 6.8 mmol g−1 (20 bar), the latter corresponding to 3 CO2 molecules adsorbed per pore per sheet. It is shown to be a semiconductor, with electrical conductivity (σ) of 3.17×10−7 S cm−1, which increases to 5.26×10−4 S cm−1 upon exposure to I2 vapor. DFT calculations using periodic conditions support the findings. The carbocationic covalent organic network called RIO‐70, obtained from inexpensive building blocks (a dye and a product derived from phloroglucinol), is a microporous material, with a specific surface area of 990 m2 g−1. It is a thermally stable, visible light‐absorbing material and semiconductor (optical band gap of 2.9 eV) with a CO2 uptake of 2.14 mmol g−1 (0.5 bar), 2.7 mmol g−1 (1 bar), and 6.8 mmol g−1 (20 bar), and is potentially interesting as a sensor or photocatalyst.