Role of weak C—H…O and strong N—H…O intermolecular interactions on the high‐symmetry molecular packing of trans‐cyclohexane‐1,4‐dicarboxamide

An unpredicted fourfold screw N—H…O hydrogen bond C(4) motif in a primary dicarboxamide (trans‐cyclohexane‐1,4‐dicarboxamide, C₈H₁₄N₂O₂) was investigated by single‐crystal X‐ray diffraction and IR and Raman spectroscopies. Electron‐density topology and intermolecular energy analyses determined from ab initio calculations were employed to examine the influence of weak C—H…O hydrogen‐bond interactions on the peculiar arrangement of molecules in the tetragonal P4₃2₁2 space group. In addition, the way in which the co‐operative effects of those weak bonds might modify their relative influence on molecular packing was estimated from cluster calculations. Based on the results, a structural model is proposed which helps to rationalize the unusual fourfold screw molecular arrangement.