Fig. 5. Solvation free energy (ΔGsolv) of unsubstituted and symmetrically substituted squaraine dyes in water, pyridine, quinoline, and isoquinoline calculated using eqn (2). Geometry optimizations were done using the M06-2X functional. The lines added to the data are to highlight trends of the data and are not meant to infer quantitative behavior. The x-axis is in order of increasing donating and withdrawing strength as its position away from SQ-H2.
