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

Abstract

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.