engleski

Weak intermolecular interactions form higher-order supramolecular structures in cytosine (Z)-4’-benzamido-2’-butenyl derivatives

From several interactions involving halogen atom those containing fluorine are especially interesting because of several reasons. Fluorine atom has very important role in medicinal chemistry as enhancer of pharmacological properties of pharmaceutical drugs. Furthermore, fluorine is introduced into the molecules in a wish to improve their metabolic stability or to modulate their physicochemical properties. It may also exert a substantial effect on the conformation of a molecule. Finally, from the matter of its importance in formation of supramolecular structure, the participation of fluorine atom has been considered to be a subject of debate. In this contribution we report structures of four cytosine (Z)-4’-benzamido-2’-butenyl derivatives (Scheme 1). In structures 2-4, hydrogen atom at 5-position of pyrimidine ring or/and at 4-position of phenyl ring is replaced with the fluorine atom. Weak C-H∙∙∙pi interactions in structures of 1 and 2 extend two dimensional networks formed by hydrogen bonds into three-dimensional networks (Fig. 1). In 3, three-dimensional network is formed by weak C-H•••F hydrogen bond (Fig. 2), so that weak intermolecular interactions in 1-3 generate higher-order supramolecular structures. Strong intermolecular interactions in 4 overruled weaker ones, so that two-dimensional network is maintained (Fig. 3).

X-ray structure; supramolecular asembling; C-H...F interactions; C-H...pi interactions

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