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 P-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 center dot center dot center dot 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.