Hydrogen-bond patterns of dialkylpyridone iron chelators and their 1:1 formic acid solvates: description, prediction, and role in crystal packing.
The crystal structures (determined from single-crystal X-ray diffraction studies) and hydrogen-bond patterns of three crystalline 1,2-dialkyl-3-hydroxy-4-pyridones and their 1:1 formic acid solvates are elucidated. The primary hydrogen-bond connectivities observed are explained by a model that predicts that the best donor bonds to the best acceptor. Relative hydrogen-bond donating and accepting abilities of the functional groups observed in these compounds are evaluated by a combination of pKas, energy calculations, resonance arguments, and crystallographic evidence. The primary (O--H ... O) hydrogen-bond patterns are described by graph set notation, and brief explanations of the graph set assignments are also included. A total of 17 secondary (C--H ... O) hydrogen bonds are also observed in these six structures. Correlations are drawn between the observed C--H ... O hydrogen bonds and the molecular packing. The possible role of these secondary hydrogen bonds in influencing molecular packing is discussed.
Ghosh
S
S
Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis 55455.
Adsmond
D A
DA
Huotari
J
J
Grant
D J
DJ
D018360:Crystallography, X-Ray; D005561:Formates / Q000737:chemistry*; D006860:Hydrogen Bonding; D007502:Iron Chelating Agents / Q000737:chemistry*; D008968:Molecular Conformation; D011728:Pyridones / Q000737:chemistry*
D005561:Formates; D007502:Iron Chelating Agents; D011728:Pyridones