Schiff bases as possible hydrogen bond donors and acceptors

• Published in: Journal of molecular structure 2021-06, Vol.1234, p.130136, Article 130136
• Main Authors: Sánchez-Pacheco, Addi Dana, Hernández-Vergara, Mónica, Jaime-Adán, Everardo, Hernández-Ortega, Simón, Valdés-Martínez, Jesús
• Format: Article
• Language: English
• Subjects: Crystal engineering; Hirshfeld surface; Hydrogen bonds; Schiff bases; π–π Stacking
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2021.130136

•We show that Schiff bases can act as H-bond donors and acceptors.•The H-bond interactions of Schiff bases are relevant to build the crystal structure.•We highlight the importance to consider molecule to molecule interactions. The compound (E)-N-(2,4-difluorophenyl)-1-(4-pyridinyl)methanimine monohydrate (1) was synthesized, characterized spectroscopically and by X-ray crystallography. 1 crystallizes in the non-centrosymmetric C2 space group with Z=4 (two organic molecules, 1a and 1b, and two water molecules). The crystal structure presents O–H···N, non-classical C–H···X hydrogen-bonds, and π–π stacking interactions. Hirshfeld Surface studies confirmed these interactions. The main intermolecular interactions are the π–π between the pyridine and the fluorinated ring of molecules stacking in columns (1a with 1a and 1b with 1b) and the O–H···N H-bonds. The imine acts as a H-bond-donor to the water molecules and a H-bond-acceptor of the water molecule's hydrogen atoms. The energy frameworks show significant interactions between molecules that are not easy to identify by geometric parameters, indicating the convenience of energy calculations to understand crystal structures better.