Novel keto-enol tautomerism in 1,3,5-trihydroxybenzene systems

• Published in: Chemical communications (Cambridge, England) Vol. 56; no. 85; pp. 12985 - 12988
• Main Authors: Ruaysap, Makabodee, Kennedy, Stuart R, Mayhan, Collin M, Kelley, Steven P, Kumari, Harshita, Deakyne, Carol A, Atwood, Jerry L
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 27.10.2020
• Subjects: Conductors; Crystallography; Hydrogen bonding; Hydrogen bonds; Lanthanides; Quantum chemistry; Tautomers
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/d0cc03639k

We report a new synthesis of the water-soluble compound 1,3,5-trihydroxy-2,4,6-trimethylsulfonic acid (1), which exists in two tautomeric forms (60 : 40::enol%:keto%) and can be used as a proton conductor. Quantum chemical calculations show the importance of intramolecular hydrogen bonding and the presence of implicit MeOH solvent on the relative stabilities of the tautomers. 1 complexes with lanthanides through its sulfonato groups and forms a layered cage-like structure with one intramolecular and two intermolecular hydrogen bonds. We report a new synthesis of the water-soluble compound 1,3,5-trihydroxy-2,4,6-trimethylsulfonic acid (1), which exists in two tautomeric forms (60 : 40::enol%:keto%), and its lanthanide complexes. Relative tautomer stability is influenced by intramolecular H-bonding and competing implicit solvent effects.