Hydrogen Bonding in Redox-Modulated Molecular Recognition. An Experimental and Theoretical Investigation GrayMark CuelloAlejandro O. CookeGraeme RotelloVincent M. 2003 Two receptors, a diaminotriazine derivative (<b>DAT</b>) and diamidopyridine (<b>DAP</b>), are complementary to the electroactive naphthalimide (<b>N</b>) through three-point hydrogen bonding. The association constants of the two receptors were evaluated for both the fully oxidized and the radical anion forms of <b>N</b>. In the oxidized state, the two receptors displayed identical binding constants. Diamidopyridine, however, lowers the reduction potential of naphthalimide to a far greater extent than does diaminotriazine, indicating a greater affinity for diamidopyridine by naphthalimide in the radical anion form. This behavior was mirrored by EPR experiments that showed small deviations from the hyperfine coupling pattern of <b>N</b><b><sub>red</sub></b> in the presence of <b>DAT</b>, with greater effects seen for the <b>N</b><b><sub>red</sub></b><b>ยท</b><b>DAP</b> complex. Computational simulations using the UB3LYP/6-311+G(d,p)//UHF/6-31G(d) hybrid gave theoretical hyperfine constants in good quantitative agreement with the experimental results. Using this correlation, we determined that electrostatics and hydrogen bond polarizability play key roles in controlling redox-modulated molecular recognition.