A:C), both bases were started with a similar Cartesian coordinate system as described for H-bonding profiles and then rotated. For stacked profiles, hydrogen caps were used instead of methyls to avoid methyl-methyl collisions. All EDA-DFT computations were performed with Q-Chem 5.3 using the ωB97X-V density functional and the aug-pc-2 basis set (triple zeta quality) unless otherwise specified.