Abstract
Croconic acid reacts in superacidic solutions HF/MF5 (M = As, Sb) to yield its corresponding salts [H3O5C5][MF6] and [(H3O5C5)H(H3O5C5)][MF6]3·2HF (M = As, Sb). The degree of protonation is strongly dependent on the stoichiometric ratio of the Lewis acid regarding croconic acid. Monoprotonated salts were characterized by vibrational spectroscopy and in the case of [H3O5C5][AsF6] (1) by a single‐crystal X‐ray structure analysis. [H3O5C5][AsF6] crystallizes in the monoclinic space group P21/c with four formula units per unit cell. The sesquiprotonated species of croconic acid [(H3O5C5)H(H3O5C5)][SbF6]3·2HF (4) was also characterized by single‐crystal X‐ray structure analysis. It crystallizes in the triclinic space group P1 with one formula unit per unit cell. The vibrational spectra of the monoprotonated salts were compared to quantum chemical calculations of the [H3O5C5]+·3HF cation and experimental data reported for croconic acid.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
