engleski

Sustainability of the robust pyridone homosyntone in halogen-bonded cocrystals

It is well known that species containing 2- pyridone (pdon) fragment easily undergo tautomerization process which includes two tautomeric forms – lactame and lactime [1]. In solid state, both tautomers can aggregate in robust hydrogen-bonded dimers by pyridone homosynthon involving two N–H∙∙∙O or O–H∙∙∙N hydrogen bonds [2]. Constancy of such dimers is well described in papers dealing with multicomponent hydrogen-bonded systems [3], while their coexistence with halogen bonds in organic solids has not been noticed to date. To investigate hierarchy of supramolecular interactions in such systems, we synthesized a series of halogen-bonded cocrystals of 2- pyridone and perhalogenated hydrocarbons. In all 6 prepared compounds, 2-pyridone is present in lactame form and expectedly connected in centrosymmetric dimers through two N–H∙∙∙O hydrogen bonds. Corresponding perhalogenated donors participate in I∙∙∙O halogen bonding, thus forming discrete molecular complexes (1 case) or supramolecular chains (5 cases). [1] H. W. Yang, B. M. Craven Acta. Cryst. B54 (1998) 912. [2] J. Almlöf, A. Kvick, I. Olovsson Acta. Cryst. B27 (1971) 1201. [3] C. B. Aakeröy, A. M. Beatty, M. Zou Cryst. Eng. 1 (1998) 225.

halogen bond ; cocrystal ; pyridone

nije evidentirano