Synthesis and crystal structure investigation of pyridine-2-(3′-mercaptopropanoic acid)-N -oxide

Pyridine‐2‐(3′‐mercaptopropanoic acid)‐N ‐oxide (I), is a higher homologue of 1‐oxopyridinium‐2‐thioacetic acid (II) [1]. It crystallizes in monoclinic space group P21 with a = 9.2168(2) Å, b = 4.1423(2) Å, c = 11.3904(4) Å, β = 98.65(2)°, V = 429.93(3) Å3 and Z = 2. The least‐squares refinement gave residual index R = 0.024 for 1070 observed reflections. The introduction of an additional methylene group in (II) causes a flip in the carboxylic acid group of (I) that facilitates the molecules to align infinite antiparallel chains through strong C–H···O interactions. The molecules are interlinked by O–H···O hydrogen bonding across the chains and forming an infinite screw chain along y‐direction. The molecular packing is stabilized by O–H···O and C–H···O hydrogen bonding and π‐π electron interactions. This is an important facet of the crystal packing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)