Synthesis and crystallographic, spectroscopic and computational characterization of 3,3′,4,4′-substituted biphenyls: effects of O R substituents on the intra-ring torsion angle

VADRA, NAHIR; MANZANO, VERONICA E.; CUKIERNIK, FABIO D.; SUAREZ, SEBASTIAN A.; HALAC, EMILIA B.; SLEP, LEONARDO D.; BAGGIO, RICARDO F.

Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials

Wiley

Año: 2020 vol. 76 p. 366 - 377

Presented here are the synthesis, characterization and study (using single crystal X-ray diffraction, Raman scattering, quantum mechanics calculations) of the structures of a series of biphenyls substituted in positions 3, 30, 4 and 40 with a variety of R (R = methyl, acetyl, hexyl) groups connected to the biphenyl core through oxygen atoms. The molecular conformation, particularly the torsionangle between aromatic rings has been extensively studied both in the solid aswell as in the liquid state. The results show that the compounds appearing asrigorously planar in the solid present instead a twisted conformation in the melt.The solid versus melt issue strongly suggests that the reasons for planarity are to be found in the packing restraints. A ?rule of thumb? is suggested for the design of biphenyls with different molecular conformations, based on the selection of the OR substituent.