Interaction of Vinyl-Type Carbocations, C3H5+ and C4H7+ with Molecules of Water, Alcohols, and Acetone

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-01, Vol.28 (3), p.1146
• Main Authors: Stoyanov, Evgenii S., Bagryanskaya, Irina Yu, Stoyanova, Irina V.
• Format: Article
• Language: English
• Subjects: Acetone; Alcohol; Alcohols; Carborane; carborane salt; Cations; Chemical bonds; Crystals; Dichloromethane; Hydrocarbons; Infrared spectroscopy; proton disolvate; Spectrum analysis; very strong H-bond; vinyl cation adduct; vinyl cations; Water chemistry; X-ray diffraction
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28031146

X-ray diffraction analysis and IR spectroscopy were used to study the products of the interaction of vinyl cations C3H5+ and C4H7+ (Cat+) (as salts of carborane anion CHB11Cl11−) with basic molecules of water, alcohols, and acetone that can crystallize from solutions in dichloromethane and C6HF5. Interaction with water, as content increased, proceeded via three-stages. (1) adduct Cat+·OH2 forms in which H2O binds (through the O atom) to the C=C+ bond of the cation with the same strength as seen in the binding to Na in Na(H2O)6+. (2) H+ is transferred from cation Cat+·OH2 to a water molecule forming H3O+ and alcohol molecules (L) having the CH=CHOH entity. The O- atom of alcohols is attached to the H atom of the C=C+-H moiety of Cat+ thereby forming a very strong asymmetric H–bond, (C=)C+-H⋅⋅⋅O. (3) Finally all vinyl cations are converted into alcohol molecule L and H3O+ cations, yielding proton disolvates L-H+-L with a symmetric very strong H-bond. When an acetone molecule (Ac) interacts with Cat+, H+ is transferred to Ac giving rise to a reactive carbene and proton disolvate Ac-H+-Ac. Thus, the alleged high reactivity of vinyl cations seems to be an exaggeration.