Interplay of hydrogen bonding and π–π interactions in the molecular complex of 2,6-lutidine N-oxide and water

The crystal and molecular structure of 2,6-lutidine N-oxide monohydrate (1) has been determined by X-ray diffraction analysis. Each water molecule is acting as bridging ligand between the N→O moieties of two 2,6-lutidine N-oxide molecules through moderate strong intermolecular hydrogen bonding (O–H⋯O, O⋯O distances are 2.787(2) and 2.832 (2) Å) giving rise to a one-dimensional (1D) polymeric helical chain. A two-dimensional (2D) layered network is then formed by self-assembly of 1D helical chains via strong π–π interactions of the aromatic rings (interplanar distances 3.385 Å). The molecular structure of 1 is compared with that for the already reported molecular structures of 2-acetylamino-6-methylpyridine N-oxide monohydrate and pyridine trihydrate. Finally, on the basis of the present studies a possible explanation for the formation of the molecular complexes is proposed and discussed.