Subject: keto/enolate TS structure in Solvation model

From: "yonyang" <yonyang!at!ic.sunysb.edu>
Date: Mon, 01 Dec 2003 14:46:11 GMT

Dear CCL users:
I am playing around with a keto/enolate formation reaction catalyzed by
gernal acid and base(methyl amine/ammonium ion). I would like to locate
the TS structure in organic solvent such as THF or cyclohexane based on
the TS structure previously located in gas phase. Despite semi-empirical
method AM1 in spartan was able to locate the initial strucuture in
organic
solvation, but further optimization in Gaussian was unsuccesful and
failed
many times.(Gaussian program complain that there is no negative engien
vector
while desired one)I am not sure if the initial structure located in
spartan was
not good enough or there was some trap in refinement in Gaussian.Can
anybody 
with experiences of this kind of reaction in solvation give me any
suggestions?
Your answer will be highly appreciated! Have a good one.

The keyword I am using in SCRF caculation

#HF/6-31G(d) OPT=(Tight,TS) SCRF=(PCM,Read,Solvent=THF) Freq Test

I also attached the PDB file of the TS in gas phase (located in
HF/6-31G(d))
and the TS in hexadacane and water.( located in AM1 ) if you are
interested.

Cheers

Yong. L. Y. 

(o)631-632-5796
Department of Chem.
SUNY-Stony Brook