Subject: Excited Phenolic Acidity AM1

From: "Jason Lye" <[email-masked]>
Date: Tue, 13 May 1997 17:23:21 -0400

Dear Colleagues,

It has been known for quite some time that the acidity of phenols is increased
in the excited state.  I am using CAChe MOPAC, specifically AM1, to try to
estimate substituent effects on the acidity of phenolic protons in the first
excited state.  The phenols that I am studying undergo excited state
intramolecular proton transfer, and I am assuming that I can faciliate this
internal conversion process by increasing the excited state acidity of the
phenolic proton.

How can I use CAChe MOPAC to estimate the acidity of a proton in the first
excited state?  (So far, I have used CAChe ProjectLeader to calculate the
partial charge on the proton, but the values that it gives are always the
ground state partial charges, not the excited state partial charges, even if
the molecule SCF energy was calculated using EXCITED SINGLET keywords.)

I will summarise any responses.

Thanks,

Jason

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Jason Lye,                       |    
Dye Synthesis Research Group,    |    
College Of Textiles,  Box 8301,  |            "Lifes' cheap, but
North Carolina State University, |       the accessories will kill you!"
Raleigh, N.C. 27695 - 8301       |                   
                                 |      
      Ph:   (919) 515-6615       |                     
      [email-masked]           |         
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