Subject: CCL:Mopac-conjugated system

From: [email-masked] (Soaring Bear)
Date: Thu, 5 Sep 1996 16:32:41 -0700

Hello:
        My question concerns using MOPAC to calculate charge
distribution in a conjugated system, like this:

                    O         +
                    ||        NR2
              // \  /\   /\  /H
             //   \/  \ /  \/
             |    ||   N
             |    ||
             \\   //
              \\ /

        I'm finding that putting various substituents around
the ring at various positions does NOT affect the charge on the
benzylic carbonyl.   The carbon & oxygen keep coming up within
a couple hundredths of a charge even though there ought to be
some conjugation/resonance with the ring and substituents.
        The MOPAC parameters I'm using (left over from previous
work) are:   AM1  Pulay  ESP  XYZ  Charge=1  GEO-OK

        My question is: Is there some other set of commands
that would work better with this system?

thankyou,
Soaring Bear

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