Partially reduced thiochromene based oxathiahelicenes: crystallographic, computational and Hirschfeld surface analyses

Abstract

An efficient and concise route for the construction of thiochromene based oxahelicenes in which heteroatoms are located on the outer helix through base-induced ring transformation of 4-sec.amino-2-oxo-2,5-dihydrothiochromeno[4,3-b]pyran-3-carbonitriles by thiochroman-4-one, 1-indanone and 2-indanone separately has been described. The X-ray studies for P and 4a show the formation of supramolecular structures through weak C–H⋯O and C–H⋯N intermolecular interactions. Supramolecular chains in 6a through C–H⋯N and π⋯π and in 7via C–H⋯π and π⋯π weak and intermolecular interactions have been observed. The detail analyses of Hirschfeld surface and fingerprint plots gave a comparative picture of the modes of non-covalent interactions in the newly synthesized compounds. The stabilization energies associated with these weak interactions have been estimated using DFT and AIM theory calculations.