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.
Item Type: | Journal article |
---|---|
Faculties: | Chemistry and Pharmacy > Department of Chemistry |
Subjects: | 500 Science > 540 Chemistry |
URN: | urn:nbn:de:bvb:19-epub-106983-9 |
ISSN: | 1434-1948 |
Language: | English |
Item ID: | 106983 |
Date Deposited: | 11. Sep 2023, 13:46 |
Last Modified: | 09. Oct 2023, 19:54 |
DFG: | Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 491502892 |