ja035228b_si_001.pdf (108.75 kB)
Hydrogen Bonding in Redox-Modulated Molecular Recognition. An Experimental and Theoretical Investigation
journal contribution
posted on 2003-06-10, 00:00 authored by Mark Gray, Alejandro O. Cuello, Graeme Cooke, Vincent M. RotelloTwo receptors, a diaminotriazine derivative (DAT) and diamidopyridine (DAP), are complementary
to the electroactive naphthalimide (N) 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 N. 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 Nred in the presence of DAT, with
greater effects seen for the Nred·DAP 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.