Table 1. Energies (activation barriers) and transition normal mode (cm-1) for the stationary point structures R=R'=H.  

Level of theory

GS Fax (Feq)

TS F-C extrusion

n1

TS Fax-ax

interconversion

n1

TS C-C extrusion

n1

1, W=i, Z=F, X=Y=H

RHF/3-21G(d)

-7138.3465

-7138.2780 (43.0)

634 i

-7138.2876 (37.0)

263 i

-7138.2550 (57.4)

741 i

B3LYP/3-21G(d)

-7142.4747

-7142.4338 (25.7)

456 i

-7142.4374 (23.4)

181 i

-7142.4196 (34.6)

544 i

MP2/3-21G(d)

-7138.3395

-7138.2702 (43.5)

520 i

RHF/DZVP

-7168.9113

-7168.8520 (37.2)

624 i

-7168.8668 (27.9)

184 i

-7168.8210 (56.7)

758 i

B3LYP/DZVP

-7173.0989

-7173.0592 (24.9)

450 i

-7173.0681 (19.3)

171 i

-7173.0467 (32.7)

552 i

RHF/Sadlej pVTZ

-7169.7176

-7169.6517 (41.3)

627 i

-7169.6685 (30.8)

192 i

-7169.6228 (59.4)

780 i

B3LYP/Sadlej pVTZ

-7173.8150

-7173.7698 (28.4)

472 i

-7173.7813 (21.1)

171 i

-7173.7602 (34.4)

566 i

MNDO-d

107.0

166.6 (59.6)

922 i

126.1 (19.1)

156 i

158.9 (52.07)

822 i

2, W=Br, Z=F, X=Y=H

RHF/3-21G(d)

-2810.6381

-2810.6067 (19.7)

563 i

-2810.5875 (31.7)

261 i

-2810.5699 (42.8)

732 i

B3LYP/3-21G(d)

-2813.8240

-2813.8095 (9.1)

382 i

-2813.7940 (18.8)

204 i

-2813.7876 (22.9)

533 i

RHF/DZVP

-2823.5949

-2823.5662 (18.0)

529 i

-2823.5610 (21.2)

169 i

-2823.5244 (44.2)

725 i

B3LYP/DZVP

-2826.8787

-2826.8606 (11.4)

367 i

-2826.8542 (15.4)

178 i

-2826.8438 (21.9)

527 i

RHF/Sadlej pVTZ

-2824.1726

-2824.1420 (19.2)

540 i

-2824.1369 (22.4)

172 i

-2824.1010 (44.9)

736 i

B3LYP/Sadlej pVTZ

-2827.3714

-2827.3507 (13.0)

385 i

-2827.3450 (16.6)

187 i

-2827.3351 (22.8)

544 i

MNDO-d

136.4

179.4 (42.9)

842 i

144.4 (8.0)

27 i

173.9 (37.5)

769 i

3, Ph2IF

RHF/3-21G(d)

-7444.4008

-7444.3341 (41.8)

562 i

-7444.3354 (41.0)

212 i

-7444.3089 (57.7)

429 i

B3LYP/3-21G(d)

-7450.6227

-7450.5769 (28.8)

371 i

-7450.5746 (30.2)

131 i

-7450.5592 (39.8)

314 i

MNDO-d

57.2

110.6 (53.4)

855 i

74.0 (16.8)

127 i

110.9 (53.7)

690 i