Subject: radical calc's on toluene derivatives

From: [email-masked] (Thomas Fox)
Date: Fri, 14 Jan 94 22:43:46 PST

Hi Netters,

to understand the substrate specifity of the enzym
chloroperoxidase a litte better and to get some insight
into the reaction mechanism, I'm presently performing
ab-initio calculations on various toluene derivatives. I'm 
especially interested in the relative energies of
the closed shell molecules and those with an electron
or a proton abstracted.

Now my questions:
- how reliable are UHF/6-31G* or MP2-UHF/6-31G* energies
  for these systems. I have no feeling how good(?) MP2 is for
  radical energies. Any experiences out on the net?

- Does anyone know some good references for radical 
  calculations that I could look up?

- Any experience with nitrobenzene or nitrotoluene? I see
  a rather high effect on the energies when turning on correlation,
  and I also get a rather high spin contamination (S**2 about 1.8)
  for nitrotoluene. Any references that cover this topic?

Thanks for your help, posted or directly mailed. If there is
enough interest, I will post a summary.

Th. Fox

__________________________________________________________________
Thomas Fox                               e-mail: [email-masked]
Dept. of Pharmaceutical Chemistry
University of California
San Francisco, CA 94143-0446
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