NMR crystallography of 2-acylamino-6-[1 H]-pyridones: Solid-state NMR, GIPAW computational, and single crystal X-ray diffraction studies

• Published in: Journal of molecular structure 2011-12, Vol.1006 (1), p.678-683
• Main Authors: Ośmiałowski, Borys, Kolehmainen, Erkki, Ikonen, Satu, Ahonen, Kari, Löfman, Miika
• Format: Article
• Language: English
• Subjects: Congeners; crystallography; crystals; Derivatives; GIPAW calculations; Hydrogen bonding; Mathematical analysis; Molecular structure; NMR crystallography; Nuclear magnetic resonance; nuclear magnetic resonance spectroscopy; Single crystals; Tautomers; X-radiation; X-ray diffraction; X-rays
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2011.10.034

► The topology of supramolecular synthons was joined to give previously unknown molecules. ► The structure of subjected molecules was confirmed by 1H, 13C and 15N NMR techniques (including solid state). ► Intramolecular hydrogen bonding forces studied molecules to fold in the solid state. ► The GIPAW calculations perfectly join the X-ray derived and 13C and 15N CP MAS NMR data. 2-Acylamino-6-[1 H]-pyridones [acyl = RCO, where R = methyl ( 1), ethyl ( 2), iso-propyl ( 3), tert-butyl ( 4), and 1-adamantyl ( 5)] have been synthesized and characterized by NMR spectroscopy. From three congeners, 2, 3 and 5, also single crystal X-ray structures have been solved. For these derivatives GIPAW calculations acts as a “bridge” between solid-state NMR data and calculated chemical shifts based on X-ray determined geometry. In crystals all three compounds exist as pyridone tautomers possessing similar six-membered ring structure stabilized by intramolecular C O⋯HN hydrogen bond. Theoretical GIPAW calculated and experimental 13C and 15N CPMAS NMR shifts are in excellent agreement with each other.