Unraveling the role of non-covalent interactions to determine chiral selectivity in coordination compounds of racemic 1,2-dihydroquinazolinone ligands

Abstract

Herein we have described crystal structures of Ni(II), Cu(II), Zn(II) and Cd(II) compounds of four racemic 1,2-dihydroquinazolinone based chelating ligands (L1–L4). The substituents on the ligands were varied by imidazolyl, pyrazinyl, 4-phenylpyridyl and quinolinyl to witness the effect of steric hindrance, hydrogen bonding and π⋯π stacking interactions on the crystal packing of coordination compounds. Supramolecular network in the coordination compounds are stabilized by non-classical hydrogen bonds viz. Csingle bondH⋯O, Csingle bondH⋯N, Csingle bondH⋯π, Nsingle bondH⋯π, in addition to strong Nsingle bondH⋯N/Nsingle bondH⋯O hydrogen bonds and parallel displaced π⋯π stacking interaction. The intermolecular interactions work either in chiral self-recognizing or self-discriminating manner depending on their strength. In addition, steric hindrance of the substituents play a crucial role and in some cases predominates over intermolecular interactions in determining the self-assembly of these coordination compounds.