Triel Bond Formed by Malondialdehyde and Its Influence on the Intramolecular H-Bond and Proton Transfer

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 18; p. 6091
• Main Authors: Wu, Qiaozhuo, Yang, Shubin, Li, Qingzhong
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2022; MDPI
• Subjects: Biomarkers; Bonds; Carbon; Carbonyl compounds; Carbonyls; Chemical bonds; Energy; Hydrogen bonding; Hydrogen bonds; Malondialdehyde; NBO; proton transfer; Protons; triel bond
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27186091

Malondialdehyde (MDA) engages in a triel bond (TrB) with TrX3 (Tr = B and Al; X = H, F, Cl, and Br) in three modes, in which the hydroxyl O, carbonyl O, and central carbon atoms of MDA act as the electron donors, respectively. A H···X secondary interaction coexists with the TrB in the former two types of complexes. The carbonyl O forms a stronger TrB than the hydroxyl O, and both of them are better electron donors than the central carbon atom. The TrB formed by the hydroxyl O enhances the intramolecular H-bond in MDA and thus promotes proton transfer in MDA-BX3 (X = Cl and Br) and MDA-AlX3 (X = halogen), while a weakening H-bond and the inhibition of proton transfer are caused by the TrB formed by the carbonyl O. The TrB formed by the central carbon atom imposes little influence on the H-bond. The BH2 substitution on the central C-H bond can also realise the proton transfer in the triel-bonded complexes between the hydroxyl O and TrH3 (Tr = B and Al).