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

摘要

A structural and conformational study of 3 beta-acetoxy-17-chloro-16-formyl-5 alpha-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 center dot center dot center dot Cl intramolecular interactions. A detailed investigation of C-H center dot center dot center dot Cl and C-H center dot center dot center dot 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.