Unexpectedly High Acidity of Water-Soluble Phosphacoumarins
In this work, we report the one-pot synthesis and characterization of four water-soluble 2-hydroxybenzo[e][1,2]oxaphosphinine 2-oxides. The compounds were obtained by cascade reactions of (2-ethoxyvinyl)phosphonic dichloride with phenol or naphthol derivatives, and their acid–base, structural, and photophysical properties were investigated using a combination of experimental and computational methods. These compounds exhibit UV–vis absorption maxima at 209–341 nm and fluorescence maxima at 300–394 nm. Notably, these cyclic phosphonic acids exhibit unusually strong acidity with pKa values from −1.3 to 0, comparable to mineral acids; complete protonation is not achieved even in concentrated HCl. The acidity trends and spectra were further analyzed by DFT using both explicit and implicit solvation models.
Authors
- Алена В. Залалтдинова (ORCID: https://orcid.org/0000-0002-4822-7330)
- Timur Yu. Ivanenko (ORCID: https://orcid.org/0000-0002-1931-3205)
- Marina A. Gerasimova (ORCID: https://orcid.org/0000-0001-8445-2714)
- Maxim A. Lutoshkin (ORCID: https://orcid.org/0000-0002-3212-4206)
- Nurbol Appazov (ORCID: https://orcid.org/0000-0001-8765-3386)
- А. Р. Бурилов (ORCID: https://orcid.org/0000-0003-2938-7352)
- Almir S. Gazizov (ORCID: https://orcid.org/0000-0001-9899-9606)
- Nurgali Akylbekov (ORCID: https://orcid.org/0000-0002-7584-9741)
- Yulia M. Sadykova (ORCID: https://orcid.org/0000-0003-2093-2860)
- Klara Kh. Darmagambet (ORCID: https://orcid.org/0000-0003-4328-5686)
- Valeriy D. Levandovski
Institutions
- Krasnoyarsk Scientific Center (RU)
- Institute of Chemistry and Chemical Technology (RU)
- Korkyt Ata Kyzylorda State University (KZ)
- A.E. Arbuzov Institute of Organic and Physical Chemistry (RU)
- Siberian Federal University (RU)
Publication Details
- Journal
- Chemistry
- Published
- 2025-11-03
- DOI
- https://doi.org/10.3390/chemistry7060175
- Primary Topic
- Organophosphorus compounds synthesis
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Siberian Branch, Russian Academy of Sciences
- Russian Science Foundation
- Russian Academy of Sciences