Electronic structure calculations were performed in Gaussian G09 rev d01 with the B3LYP hybrid functional and the 6-31G(d,p) basis set with Grimme's GD3 dispersion correction with Becke-Johnson damping (GD3BJ), and counterpoise correction for hydrogen-bonded complexes. The absence of imaginary frequencies in a subsequent frequency calculation confirms that the resultant structures are indeed an energy minimum. We generated electrostatic potential (ESP) isosurfaces (electron density maps from total SCF density mapped with ESP) for the complexes at the B3LYP-GD3BJ/6-31G(d,p) level of DFT using Gaussian G09 rev d01.