Novel Fluorinated Biphenyl Compounds Synthesized via Pd(0)-Catalyzed Reactions: Experimental and Computational Studies

Abstract

Five new difluorinated biphenyl compounds, 4′-(tert-butyl)-3,4-difluoro-1,1′-biphenyl (TBDFBP), 1-(3′,4′-difluoro-[1,1′-biphenyl]-4-yl)­ethanone (DFBPE), 3′,4′-difluoro-2,5-dimethoxy-1,1′-biphenyl (DFDMBP), 3,4-difluoro-3′-nitro-1,1′-biphenyl (DFNBP), and (3′,4′-difluoro-[1,1′-biphenyl]-3-yl)­(methyl)­sulfane (DFBPMS), have been successfully synthesized by the well-known Suzuki–Miyaura coupling with excellent yields averaging 78%. UV–visible, Fourier transform infrared ,and 13C NMR and 1H NMR spectroscopies along with single-crystal X-ray diffraction (SC-XRD) analysis (for TBDFBP and DFBPE) were used for the structure elucidation of the synthesized compounds. The SC-XRD results demonstrated the crystal systems of the studied compounds, TBDFBP and DFBPE, to be monoclinic, and their space groups were found to be P21/c. Also, a detailed density functional theory study was performed. The calculated structures for TBDFBP and DFBPE were found to agree quite well with the experimental results. The natural bonding orbital charge analysis suggested that molecules of these compounds should interact quite noticeably with each other in the solid phase and with polar solvent molecules. Molecular electrostatic potential analysis suggests that accumulation of positive and negative potential implies possibility of quite significant dipole–dipole intermolecular interactions in crystals of these compounds, as well as quite strong interactions with polar solvent molecules. The global reactivity parameters analysis suggests all compounds to be quite stable in redox reactions, with the compound DFNBP being relatively more reactive and the compounds TBDFBP and DFDMBP being relatively more stable.