T
he knowledge of accurate bond strengt
hs is a fundamental basis for a
pro
per analysis of c
hemical reaction mec
hanisms. Quantum c
hemical calculations at different levels of t
heory
have been used to investigate
heterolytic Fe&ndas
h;O and Fe&ndas
h;S bond energies of (meta-substituted
phenoxy)dicarbonyl(η
p>5p>-cyclo
pentadienyl) iron [
m-G-C
6H
4OF
p (
href="#poc3582-eo-0001" rel="references:#poc3582-eo-0001">)] and (meta-substituted benzenet
hiolato)dicarbonyl(η
p>5p>-cyclo
pentadienyl) iron [
m-G-C
6H
4SF
p (
href="#poc3582-eo-0002" rel="references:#poc3582-eo-0002">)] com
plexes. In t
his study, F
p is (η
p>5p>-C
5H
5)Fe(CO)
2, and G is NO
2, CN, COMe, CO
2Me, CF
3, Br, Cl, F, H, Me, MeO, and NMe
2. T
he results s
how t
hat Tao&ndas
h;Perdew&ndas
h;Staroverov&ndas
h;Scuseria and Becke's
power-series ansatz from 1997 wit
h dis
persion corrections functionals can
provide t
he best
price/
performance ratio and accurate
predictions of Δ
Hhet(Fe&ndas
h;O)'s and Δ
Hhet(Fe&ndas
h;S)'s. T
he excellent
linear free energy relations [
r&t
hins
p;=&t
hins
p;1.00 (g, 1e), 1.00 (g, 2b)] among t
he ΔΔ
Hhet (Fe&ndas
h;O)'s and δΔ
Gp>0p> of OH bonds of
m-G-C
6H
4OH or ΔΔ
Hhet(Fe&ndas
h;S)'s and Δ
pKa's of SH bonds of
m-G-C
6H
4SH im
ply t
hat t
he governing structural factors for t
hese bond scissions are similar. And, t
he
linear correlations [
r&t
hins
p;=&t
hins
p;−0.97 (g, 1&t
hins
p;g), −0.97 (g, 2&t
hins
p;
h)] among t
he ΔΔ
Hhet (Fe&ndas
h;O)'s or ΔΔ
Hhet(Fe&ndas
h;S)'s and t
he substituent σ
m constants s
how t
hat t
hese correlations are in accordance wit
h Hammett
linear free energy relations
hi
ps. T
he inductive effects of t
hese substituents and t
he basis set effects influence t
he accuracy of Δ
Hhet(Fe&ndas
h;O)'s or Δ
Hhet(Fe&ndas
h;S)'s. T
he ΔΔ
Hhet(Fe&ndas
h;O)'s(g) (1) and ΔΔ
Hhet(Fe&ndas
h;S)'s(g)(2) follow t
he ca
pto-dative Princi
ple. T
he substituent effects on t
he Fe&ndas
h;O bonds are muc
h stronger t
han t
hose on t
he less
polar Fe&ndas
h;S bonds. Insig
ht from t
his work may
hel
p t
he design of more effective catalytic
processes. Co
pyrig
ht