Subject: redox potentials from MO work

From: [email-masked]
Date: Fri, 19 May 1995 11:22:00 -0400

Part of my own interest in computation of redox potentials using 
     Hyperchem is in determination of antioxidant activity. For a class of 
     similar antioxidants, I tend to get good correlation between 
     antioxidant activity and heat of reaction for one-electron oxidantion 
     of antioxidant, but the correlation breaks down when comparing 
     different classes of antioxidant.
     
     I consider this to be a limitation of a gas-phase model, where the 
     change in 'molecular environment' for similar antioxidants should be 
     about the same and thus cancel, but for widely different antioxidants, 
     the effect of solution stabilization, polarization, etc., is different 
     and produces a different effect.
     
     I have attempted to correlate excitation energies with antioxidant 
     activity to no avail.
     
     I would imagine that the environment to which the electron is being 
     transferred might affect the redox potential, since redox is always 
     measured experimentally in reference to a particular 'electrode' and 
     ionization is measured computationally with the electron going off 
     into 'nothingness'.
     
     matt harbowy
     who can't speak authoritatively on redox to save his soul,
     nor is elucidating the views of thomas j. lipton, inc.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;