Inhibition by Water during Heterogeneous Brønsted Acid Catalysis by Three-Dimensional Crystalline Organic Salts

Crystal Growth and Design, United States. 2021. Vol. 21. No. 11. P. 6364–6372.

Gak A., Kuznetsova S., Nelyubina Y., Korlyukov A., Li H., North M., Zhereb V., Riazanov V., Peregudov A., Ekaterina Khakina, Lobanov N., Khrustalev V., Belokon Y.

A new self-assembled and self-healing class of metal free, recyclable, heterogeneous Brønsted acid catalysts has been developed by the protonation of aniline derivatives (tetrakis(4-aminophenyl)methane, leuco-crystal violet, benzidine, and p-phenylenediamine) with aromatic sulfonic acids (tetrakis(phenyl-4-sulfonic acid)methane, and 2,6-naphthalenedisulfonic acid). As a result, five three-dimensional crystalline organic salts were obtained, linked by hydrogen bonds and additionally stabilized by the opposite charges of the components. The catalytic activities of crystalline organic salts have been explored in industrially important epoxide ring-opening and acetal formation reactions. The presence of encapsulated water inside frameworks and had an inhibitory effect on the performance of the catalysts. X-ray diffraction analysis of hydrated and dehydrated samples of and indicated that water of crystallization served as a cross-linking agent, diminishing the substrate induced “breathing” affinities of the frameworks.

Keywords: catalysts, molecules, noncovalent interactions