Binuclear hexafluorocyclopentadiene iron carbonyls: bis(dihapto) versus trihapto-monohapto bonding in iron-iron bonded structuresElectronic supplementary information (ESI) available: Tables S1-S6: coordinates of (C5F6)Fe(CO)n (n = 4, 3, 2); Tables S7-S22: coordinates of (C5F6)Fe2(CO)n (n = 8, 7, 6, 5); Tables S23-S28: harmonic vibrational frequencies (cm−1) and IR intensities (km mol−1) of (C5F6)Fe(CO)n (n = 4, 3, 2); Tables S29-S44: harmonic vibrational frequencies (cm−1) and IR intensities (km
Binuclear organometallic systems incorporating free cyclopentadiene (C 5 H 6 ) as a ligand rather than the ubiquitous cyclopentadienyl ligand (C 5 H 5 ) have never been reported in the literature. However, the hexafluorocyclopentadiene ligand (C 5 F 6 ) is known to form the stable binuclear carbonyl...
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| Main Authors | , , , , |
|---|---|
| Format | Journal Article |
| Language | English |
| Published |
12.08.2013
|
| Online Access | Get full text |
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| Summary: | Binuclear organometallic systems incorporating free cyclopentadiene (C
5
H
6
) as a ligand rather than the ubiquitous cyclopentadienyl ligand (C
5
H
5
) have never been reported in the literature. However, the hexafluorocyclopentadiene ligand (C
5
F
6
) is known to form the stable binuclear carbonyl derivatives (η
2
,η
2
-C
5
F
6
)Fe
2
(CO)
8
and
trans
-(η
3
,η
1
-C
5
F
6
)Co
2
(CO)
7
. The related hexafluorocyclopentadiene iron carbonyl systems (C
5
F
6
)Fe(CO)
n
(
n
= 4, 3, 2) and (C
5
F
6
)Fe
2
(CO)
n
(
n
= 8, 7, 6, 5) have now been explored using density functional theory. The hexafluorocyclopentadiene ligand is found to use one or both of its C&z.dbd;C double bonds to bind either as a dihapto η
2
-C
5
F
6
monoolefin or a tetrahapto η
4
-C
5
F
6
diolefin in mononuclear (C
5
F
6
)Fe(CO)
n
structures. In binuclear iron carbonyl structures lacking direct iron-iron bonds, such as the lowest energy
trans
- and
cis
-(η
2
,η
2
-C
5
F
6
)Fe
2
(CO)
8
structures as well as higher energy
trans
-(η
2
,η
2
-C
5
F
6
)Fe
2
(CO)
n
(
n
= 7, 6, 5) structures, the hexafluorocyclopentadiene ligand binds as a bis(dihapto) diolefin. However, the lowest energy (C
5
F
6
)Fe
2
(CO)
n
(
n
= 7, 6, 5) structures have
cis
stereochemistries with direct iron-iron bonds of orders ranging from one to three. In such lowest energy structures the hexafluorocyclopentadiene ligand is bonded to the Fe
2
unit as a trihapto-monohapto η
3
,η
1
-C
5
F
6
ligand.
The structures and energetics of the hexafluorocyclopentadiene iron carbonyls (C
5
F
6
)Fe
2
(CO)
n
(
n
= 8, 7, 6, 5) are explored using density functional theory. |
|---|---|
| Bibliography: | 8, 7, 6, 5); Tables S23-S28: harmonic vibrational frequencies (cm and Δ Electronic supplementary information (ESI) available: Tables S1-S6: coordinates of (C imag), and Fe-Fe bond distances (in Å) for binuclear (C E F of (C ZPVE 8, 7, 6, 5); Tables S45-S46: total energies in kcal mol imag) for mononuclear (C and numbers of imaginary vibrational frequencies ref. 28 4, 3, 2); Tables S29-S44: harmonic vibrational frequencies (cm and IR intensities (km mol Fe Fe(CO) 10.1039/c3nj00311f CO) frequencies of the mononuclear (C ( See DOI in Hartree), relative energies with and without ZPVE corrections (Δ CO n 8, 7, 6, 5) structures; Table S51: the 1 4, 3, 2) and binuclear (C 2 4, 3, 2); Tables S7-S22: coordinates of (C 5 6 ν 4, 3, 2) structures; Tables S47-S50: total energies 8, 7, 6, 5) derivatives (with the BP86 method); complete Gaussian reference |
| ISSN: | 1144-0546 1369-9261 |
| DOI: | 10.1039/c3nj00311f |