Interaction of thiourea and urea with maleimide: comparative theoretical DFT study
Nabila Achoui,
Karima Zaioua,
Dalila Hammoutène,
Bellara Kolli-Nedjar,
Yamina Akacem
Affiliations
Nabila Achoui
USTHB, Faculty of Chemistry, Laboratory of Thermodynamics and Molecular Modeling, BP 32, Al Alia, 16111, Bab Ezzouar, Algiers, Algeria; Corresponding author.
Karima Zaioua
USTHB, Faculty of Chemistry, Laboratory of Thermodynamics and Molecular Modeling, BP 32, Al Alia, 16111, Bab Ezzouar, Algiers, Algeria
Dalila Hammoutène
USTHB, Faculty of Chemistry, Laboratory of Thermodynamics and Molecular Modeling, BP 32, Al Alia, 16111, Bab Ezzouar, Algiers, Algeria
Bellara Kolli-Nedjar
USTHB, Faculty of Chemistry, Laboratory of Applied Organic Synthesis, BP32, El Alia, 16111, Bab Ezzouar, Algiers, Algeria
Yamina Akacem
USTHB, Faculty of Chemistry, Laboratory of Thermodynamics and Molecular Modeling, BP 32, Al Alia, 16111, Bab Ezzouar, Algiers, Algeria
A gas-phase mechanism reaction of maleimide with urea or thiourea was studied by DFT method. A comparison between atomic charges, Fukui index evaluation and Frontier orbitals theory was carried out. The involvement of pre- and post-reactive complexes was examined as the reaction profiles are modelled. For each mechanism, two approaches have been proposed through nitrogen and sulfur (for thiourea), or oxygen and nitrogen (for urea) attack. The results indicate that the carbon double bonded of maleimide is the electophilic site and chalcogen atom of chalcogenourea is the nucleophilic one. The obtained activation free energies predict suitable specie that could be generated after an opening-cycle and new bonds formation. Consequently, the sulfur attack of thiourea was promoted on oxygen (urea) which is in accordance with the experiments.
