Cyclopentadienyliron dicarbonyl iodide is an
organoiron compound with the formula (C
5H
5)Fe(CO)
2I. It is a dark brown solid that is soluble in common organic solvents. (C
5H
5)Fe(CO)
2I, or FpI as it is often known, is an intermediate for the preparation of other organoiron compounds such as in ferraboranes.
Preparation
Cyclopentadienyliron dicarbonyl iodide is synthesized by the reaction of
cyclopentadienyliron dicarbonyl dimer with I
2:
[ King, R. B.; Stone, F. G. A "Cyclopentadienyl Metal Carbonyls and some Derivatives" Inorg. Synth. 1963, volume 7, pp. 99-115. ]
:Cp
2Fe
2(CO)
4 + I
2 → 2 CpFe(CO)
2I
It was first reported by Pauson and Hallam.
[B. F. Hallam, P. L. Pauson "Ferrocene Derivatives. Part III. Cyclopentadienyliron Carbonyls" J. Chem. Soc. 1956, pp. 3031-3037.]
Structure
The compound has C
s symmetry
Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...
, with a mirror plane intersecting one carbon of the Cp ring as well as the iron and iodide centre. The compound adopts a piano stool structure: the
cyclopentadienyl Cyclopentadienyl can refer to
*Cyclopentadienyl anion, or cyclopentadienide,
**Cyclopentadienyl ligand
*Cyclopentadienyl radical, •
*Cyclopentadienyl cation,
See also
*Pentadienyl
In organic chemistry, pentadienyl refers to the organic radic ...
ligand is the "seat" and three other ligands are "legs". Such compounds are members of the
half-sandwich family of compounds, which is a subgroup of the
metallocenes.
X-ray crystallography shows the following features: Fe-Cp centroid = 1.72, Fe-I = 2.61, and Fe-CO = 1.78 Å.
Electron counting
Electron counting is a formalism used for classifying compounds and for explaining or predicting electronic structure and bonding. Many rules in chemistry rely on electron-counting:
*Octet rule is used with Lewis structures for main group eleme ...
of this iron(II) complex indicates that (C
5H
5)Fe(CO)
2I is an
18-electron complex: using the neutral method there are 8 electrons from the iron, 5 electrons from the cyclopentadienyl anion, 2 electrons from each of the carbonyls, and 1 electron from the iodide.
References
{{iron compounds
Organoiron compounds
Coordination complexes
Carbonyl complexes
Cyclopentadienyl complexes
Half sandwich compounds
Iodo complexes
Iron(II) compounds