In
organoiron chemistry, a ferrole is a type of diiron complex containing the (OC)
3FeC
4R
4 heterocycle that is
pi-bonded to a Fe(CO)
3 group. These compounds have Fe-Fe bonds (ca. 252
pm) and semi-bridging CO ligands (Fe-C distances = 178, 251 pm). They are typically air-stable, soluble in nonpolar solvents, and red-orange in color.
Synthesis
Ferroles typically arise by the reaction of
alkyne
\ce
\ce
Acetylene
\ce
\ce
\ce
Propyne
\ce
\ce
\ce
\ce
1-Butyne
In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and n ...
s with
iron carbonyls. Such reactions are known to generate many products, e.g. complexes of
cyclopentadienones and para-
quinone
The quinones are a class of organic compounds that are formally "derived from aromatic compounds uch as benzene or naphthalene
Uch ( pa, ;
ur, ), frequently referred to as Uch Sharīf ( pa, ;
ur, ; ''"Noble Uch"''), is a historic city in the southern part of Pakistan's Punjab province. Uch may have been founded as Alexandria on the Indus, a town founded by Alexand ...
by conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double ...
s.
Another route involves the desulfurization of thiophenes (SC
4R
4) by iron carbonyls, shown in the following idealized equation:
:Fe
3(CO)
12 + SC
4R
4 → Fe
2(CO)
6C
4R
4 + FeS + 6CO
An unusual route to ferroles involves treatment of
Collman's reagent
Disodium tetracarbonylferrate is the organoiron compound with the formula Na2 e(CO)4 It is always used as a solvate, e.g., with tetrahydrofuran or dimethoxyethane, which bind to the sodium cation. An oxygen-sensitive colourless solid, it is a r ...
with trimethylsilyl chloride (tms = (CH
3)
3Si):
:2Na
2Fe(CO)
4 + 4tmsCl → Fe
2(CO)
6C
4(Otms)
4 + 2CO + 4NaCl
Reactions
Some ferroles react with tertiary phosphines to give the substituted
flyover complex Fe
2(CO)
5(PR
3)(C
4R
4CO).
[{{cite book , doi=10.1016/B978-008046519-7.00058-7, chapter=Dinuclear Iron Compounds with Hydrocarbon Ligands, title=Comprehensive Organometallic Chemistry II, year=1995, last1=Fagan, first1=Paul J., pages=231–258, isbn=9780080465197]
References
Organoiron compounds
Carbonyl complexes
Trimethylsilyl compounds