From owner-chemistry@ccl.net Tue May 19 14:32:00 2015
From: "Lovija Meyer Lovija3\a/yahoo.de" <owner-chemistry^-^server.ccl.net>
To: CCL
Subject: CCL: Relative energy Vs activation barrier
Message-Id: <-51383-150519135534-754-7r6FFGf/Inj8HSTW2Nut7Q^-^server.ccl.net>
X-Original-From: "Lovija  Meyer" <Lovija3]=[yahoo.de>
Date: Tue, 19 May 2015 13:55:33 -0400


Sent to CCL by: "Lovija  Meyer" [Lovija3 _ yahoo.de]
Dear Users ( and dear Andi U. who I hope to meet here...)

The following part was an answer in 2011- but Is like to find an explanation here now...It was answered by Andi U. so I hope that hell read this to answer my question the way he did it years ago...

The answer was:

>
> in multistep reactions the single activation barriers are unimportant and
> the relative energies decide which pathway is favored. If you are interes=
ted
> in catalysis, I recommend that you have a look at the energetic span mode=
l:
>
> A) Kozuch, S.; Shaik, S. *J. Am. Chem. Soc. **2006*, *128*, 3355-3365.
> B) Kozuch, S.; Shaik, S. *J. Phys. Chem. A* *2008*, *112*, 6032-6041.
> C) Uhe, A.; Kozuch, S.; Shaik, S. *J. Comp. Chem. **2011*, *32*, 978-985.
> D) Kozuch, S.; Shaik, S. *Acc. **Chem. Res. **2011*, *44*, 101-110.
> The model shows that the concept of a rate determining reaction step
> (corresponding to a single activation barrier of a multistep reaction) is
> misleading. It also allows to calculate the turnover frequency of a
> catalytic system from relative energies e.g. obtained with DFT. Paper A
> introduces the model, paper B extends its application to the reactant
> concentrations, paper C further extends the model and introduces a small
> computer program helping to apply the model and paper D reviews the model=