Channel-forming solvate crystals and isostructural solvent-free powder of 5-hydroxy-6-methyl-2-pyridone
作者:Sean R. Parkin、Edward J. Behrman
DOI:10.1107/s0108270111026254
日期:2011.8.15
Crystals of 5-hydroxy-6-methyl-2-pyridone, (I), grown from a variety of solvents, are invariably trigonal (space group R (3) over bar); these are 5-hydroxy-6-methyl-2-pyridone acetone 0.1667-solvate, C6H7NO2 center dot 0.1667C(3)H(6)O, (Ia), and 6-methyl-5-hydroxy-2-pyridone propan-2-ol 0.1667-solvate, C6H7NO2 center dot 0.1667C(3)H(8)O, (Ib), and the forms from methanol, (Ic), water, (Id), benzonitrile, (Ie), and benzyl alcohol, (If). They incorporate channels running the length of the c axis that contain extensively disordered solvent molecules. A solvent-free sublimed powder of 5-hydroxy-6-methyl-2-pyridone micro-crystals is essentially isostructural. Inversion-related host molecules interact via pairs of N-H center dot center dot center dot O hydrogen bonds to form R-2(2)(8) dimers. Six of these dimers form large R-12(6)(42) puckered rings, in which the O atom of each N-H center dot center dot center dot O hydrogen bond is also the acceptor in an O-H center dot center dot center dot O hydrogen bond that involves the 5-hydroxy group. The large R-12(6) (42) rings straddle the (3) over bar axes and form stacked columns via pi-pi interactions between inversion-related molecules of (I) [ mean interplanar spacing = 3.254 angstrom and ring centroid-centroid distance = 3.688 (2) angstrom]. The channels are lined by methyl groups, which all point inwards to the centre of the channels.