1

F– + CF3Br

F–(CF3Br)

[FCF3Br]–

(CF4)Br–

CF4 + Br–

2

F– + CF3Br

F–(BrCF3)

CF4 + Br–

(CF4)Br–

[FCF3Br]–TS TS

ComplexF–(CF3Br)

3

F– + CF3Br

F–(CF3Br)

[FCF3Br]–

(CF4)Br–

CF4 + Br–

(FBrCF3)–

TSTS

Complex

4

5

Table 1.

Enthalpy (kcal/mol) Entry Description B3LYP//B3LYP a MPW1PW91//B3LYP b Experimental

F– + CF3Br Reactants 0.0 0.0 F–(BrCF3) Front-side attack entrance complex –31.0 –30.6 [FBrCF3]– Rotation transition state 1 –7.3 –7.1

F–(BrF2CF) Rotation complex –8.4 –8.3 [FF2CFBr]– Rotation transition state 2 –4.8 –4.6 F–(CF3Br) Back-side attack complex –8.2 –8.1 [FCF3Br]– Back-side attack transition state –7.0 –6.6 Br–(CF4) Back-side attack exit complex –61.4 –63.9 Br– + CF4 Products –59.9 –62.2 –59.4

a B3LYP/6-311+G(3df)//B3LYP/6-311+G(d) b MPW1PW91/6-311+G(3df)//B3LYP/6-311+G(d)

Computational Results

Table 2.

Enthalpy (kcal/mol) Entry Description B3LYP//B3LYP a MPW1PW91//B3LYP b Experimental

F– + CF3I Reactants 0.0 0.0 F–(ICF3) Front-side attack entrance complex –45.2 –45.7 [FICF3]– Rotation transition state 1 –8.8 –8.8

F–(IF2CF) Rotation complex –11.3 –11.8 [FF2CFI]– Rotation transition state 2 –4.8 –4.8 F–(CF3I) Back-side attack complex –8.1 –8.8 [FCF3I]– Back-side attack “transition state” –8.3 –9.1 I–(CF4) Back-side attack exit complex –70.7 –75.3 I– + CF4 Products –69.6 –74.0 –67.9

a B3LYP/[6-311+G(3df):LANL2DZdp ECP dp]//B3LYP/[6-311+G(d):LANL2DZdp ECP] b MPW1PW91//[6-311+G(3df):LANL2DZdp ECP dp]//B3LYP/[6-311+G(d):LANL2DZdp ECP]

6

722

Finding Analytical Functions

8

[CF3ClBr]–

Cl– + CF3Br

ClCF3 + Br–

Cl–(BrCF3) (CF3Cl)Br–

9

10

Cl– + CF3Br

ClCF3 + Br–

Cl–(CF3Br)

(ClCF3)Br–

[ClCF3Br]–

11

12

Cl– + CF3Br

ClCF3 + Br–

[ClCF3Br]–

Cl–(BrCF3)(CF3Cl)Br–

Cl–(CF3Br)

(ClCF3)Br–