DFT Reactivity Descriptors and Catalysis - Vrije Universiteit Brussel
DFT Reactivity Descriptors and Catalysis - Vrije Universiteit Brussel
DFT Reactivity Descriptors and Catalysis - Vrije Universiteit Brussel
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Cyclic TS characterized by several interactions of the<br />
electrophilic/nucleophilic type<br />
N<br />
Calculated TS with CH 3 F/BF 3<br />
CH 3+ attacking<br />
benzene<br />
E<br />
C m<br />
C b<br />
E<br />
H 2<br />
H + leaving<br />
benzene<br />
X - leaving<br />
CH 3 X<br />
X 1<br />
N<br />
M<br />
E<br />
X 2<br />
N<br />
C m<br />
H 3Cb<br />
X 1<br />
H 2<br />
X 3<br />
X<br />
M 2<br />
tsM_BF 3<br />
X 3<br />
X 4<br />
orbital interactions (eg vacant orbital(s) of Lewis acids) > electrostatics<br />
softness at work?<br />
HSAB at local level A ..... B s A<br />
+<br />
as close possible to s B<br />
-<br />
+ -<br />
Multicenter event: looking for smallest value of ∑( s -s ) 2<br />
A,i B,i<br />
Cfr. regioselectivity of Diels Alder reactions showing cyclic TS.<br />
S. Damoun, G. V<strong>and</strong>e Woude, F. Mendez, P. Geerlings, J.Phys.Chem.A, 101, 886 (1997)<br />
i<br />
Pag.<br />
30-9-2008 33
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