Testing the validity of the conventional resonance model for protonated carbonyl, imine and thiocarbonyl compounds. An Ab initio valence bond study.
The conventional resonance model describes protonated carbonyls, imines, and thiocarbonyls by a superposition of two structures, one pi polar-covalent and the other of carbenium type. The validity of this model is clearly supported by high level valence bond calculations, giving a 32% weight for the carbenium form in protonated carbonyl, 19% in protonated formamine and thioformaldehyde. The carbenium form is further stabilized by pi-donating substituents. Solvation effects do not fundamentally change the gas-phase picture.
Braïda
Benoît
B
UPMC Université Paris 06, UMR 7616, Laboratoire de Chimie Théorique, Case courrier 137, 4 place Jussieu, 75252 Paris, France. braida@lct.jussieu.fr
Bundhoo
Dilshaad
D
Engels
Bernd
B
Hiberty
Philippe C
PC
D000447:Aldehydes / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D008956:Models, Chemical; D011522:Protons; D011789:Quantum Theory; D015203:Reproducibility of Results; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D000447:Aldehydes; D007097:Imines; D011522:Protons; D013438:Sulfhydryl Compounds