radical calc's on toluene derivatives

 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: fox at.at saga.ucsf.edu
 Dept. of Pharmaceutical Chemistry
 University of California
 San Francisco, CA 94143-0446
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