Stabilizing the C-N Double Bond Character in Fumaramide with the Aid of Superacids

Bayer, Marie C.; Greither, Nikolaus; Bockmair, Valentin; Nitzer, Alexander und Kornath, Andreas J. (2022): Stabilizing the C-N Double Bond Character in Fumaramide with the Aid of Superacids. In: European Journal of Inorganic Chemistry, Bd. 2022, Nr. 35

Abstract

Fumaramide was reacted with the superacidic systems XF/SbF5 and XF/BF3 (X = H, D) leading to the formation of the 0-diprotonated species. Using an equimolar amount of the Lewis acids relating to fumaramide, a mixture of the diprotonated salt and the diadduct with O-coordinated HF was obtained. The salts [C4H2X6N2O2](2+)[(BF4)(-)](2) and [C4H2X6N2O2](2)center dot[(SbF6)(-)](2) (X = H, D) were characterized by low-temperature vibrational spectro-scopy. Single-crystal X-ray structure analyses were carried out for the compounds [C4H8N2O2](2+)[(BF4)(-)](2), C4H6N2O2 center dot center dot center dot 2HF, and fumaramide. To discuss the experimental results, quantum chemical calculations were executed at the B3LYP/aug-cc-pVTZ level of theory. To investigate the impact of the protonation on the resonance + M effect and the electron distribution concern- ing the conjugated system ESP maps, NPA charges, and NBO analyses were consulted. Due to the protonation, the nitrogen lone pair contributes completely to the formation of the C=N pi-bond, stabilizing the C=N double bond character. Since no monoprotonation of fumaramide is observed, amide hydrolysis is possible simultaneously on both amide groups.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 1434-1948
• Sprache: Englisch
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 491502892