Fig. 2. (A) Dihedral contour plots of a model system depicting the difference in conformational preference between benzothiazole and benzoxazole rings. The relevant dihedral angles are depicted in bold and the plots show the Boltzmann population of conformers at 298 K. (B) The model systems displayed in their most highly populated conformations (benzothiazole system in the red box and benzoxazole system in the blue box, see also the ESI†). The calculations were performed at the M06-2X/6-31G(d,p) level of theory with implicit aqueous solvent.29–34 † .
