Amide-to-Amide Hydrogen Bonds in the Presence of a Pyridine Functionality: Crystal Structures of Bis(pyridinecarboxamido)alkanes

Crystal structures of bis(4-pyridinecarboxamido)alkane and bis(3-pyridinecarboxamido)alkane derivatives were
determined and analyzed in terms of hydrogen bond networks. Seven crystal structures out of the eight structures studied exhibited
amide-to-amide hydrogen bonds. Out of these seven, five form the anticipated β-sheet network whereas two structures form a
doubly interpenetrated (4,4)-network. In only one structure does the pyridyl group interfere in the amide-to-amide hydrogen bond,
leading to the formation of an N−H···N hydrogen bond network. The analyses and rationalization of these structures and also
related derivatives in the Cambridge Structural Database suggested that amide-to-amide hydrogen bond formation depends on the
interplanar angle between amide and pyridine groups.