Unusual hydrogen bond patterns contributing to supramolecular assembly: conformational study, Hirshfeld surface analysis and density functional calculations of a new steroid derivative

Abstract

A structural and conformational study of 3β-acetoxy-17-chloro-16-formyl-5α-androstan-16-ene has been carried out by using X-ray analysis and M06-2X density functional calculations. The compound crystallizes with three independent molecules in the asymmetric unit. Natural Bond Order and Atoms in Molecules methods were used for a better understanding of the key factors that determine the stability of this steroidal molecule, particularly the role of C–H⋯Cl intramolecular interactions. A detailed investigation of C–H⋯Cl and C–H⋯O intermolecular interactions, in addition to the most important van der Waals contribution, are presented by means of Hirshfeld surface analysis. The crystal packing exhibits an unusual intra- and intermolecular hydrogen bond pattern, and shows the importance of non-classical interactions in the construction of the supramolecular assembly. Excellent agreement between the theoretical and experimental data is found.