Synthesis, experimental and theoretical study of novel 2-haloalkyl (-CF2H, -CCl2H, -CF2CF3)-, 3-bromo and bromomethyl substituted chromones

Abstract

A set of seven new chromones with 2-haloalkyl (-CF2H, -CCl2H, -CF2CF3) and 3-bromo and bromomethyl substituents were synthesized. The novel compounds were studied by DFT calculations and characterized by vibrational spectroscopy (IR and Raman) in solid state, and NMR (1H, 13C and 19F) and UV–vis spectroscopy in solution. The crystal structure of 3-dibromomethyl-2-difluoromethyl chromone was determined by X-ray diffraction. Due to extended π-bond delocalization, the organic framework is planar and lies on a crystallographic m-mirror plane. The intermolecular non-covalent interactions of 3-dibromomethyl-2-difluoromethyl chromone, as π⋯π stacking arrangements, F⋯H hydrogen bonds and O⋯Br contacts were evaluated by Hirshfeld surfaces analysis. These intermolecular contacts, which affect the absorption bands location of the involved groups, were also detected in the vibrational spectra.