Table 2.

Calculated molecular potential density maps^a

Compound	1	2	3	4
Isosteric series
Compound	5	6	7	8
Homologated series

^aMolecular electrostatic potentials were calculated at the B3LYP/6-31G^∗∗ level and mapped on 0.002 au isodensity surface and are shown with identical chromatic scales (red is more negative, greater electron density; blue is more positive, less electron density). Spartan’06, Wavefunction, Inc. Irvine, CA.