Ernst Otto Fischer demonstrated usage of organometallic or sandwich compounds in different fields. First person who predicted the structure of ‘Ferrocene’ synthetic compound.Organometallic chemistry is the study of chemical compounds containing bonds between carbon and a metal. It is the combination of inorganic chemistry and organic chemistry. Organometallic compounds can be used in stoichiometric and catalytic processes, in the production of polyethylene and polypropylene
2. Ernst Otto Fischer was born on November 10, 1918
Fischer was a German chemist and Nobel laureate
He developed new method to combine metals and organic substances
In 1955 Fischer demonstrated usage of organometallic or sandwich
compounds in different fields
In 196 His group discovered some chemical complexes called alkylidene and
alkylidyne
In 1973 He was awarded with Nobel Prize
Fischer gave lectures on
Cyclopentadienyl
Indenyl
Arenes
Olefins
Metal carbonyls
He was the first person who predicted the structure of ‘Ferrocene’ synthetic
compound
3. Organometallic chemistry is the study of chemical
compounds containing bonds between carbon and a
metal. It is the combination of inorganic chemistry
and organic chemistry. Organometallic compounds
can be used in stoichiometric and catalytic processes,
in the production of polyethylene and polypropylene.
Examples of organometallics
Iodo(methyl)magnesium
n-Butyllithium
Chloro (ethoxycarbonylmethyl)zinc
Lithium Dimethylcuprate
4. Ferrocene was accidently discovered in 1951
at Duquesne University in
Pittsburgh, Pennsylvania by T.J. Kealy and
P.L.Paulson and before Paulson its existence
was discovered by Fischer
5. Cyclopentadienyl magnesium bromide
(CpMgBr) was reacted with iron (II) chloride in
attempt to create a fulvalene. When an orange
complex formed instead, the chemists
hypothesized that the iron was bound to one
carbon in each ring.
Ferrocene’s cyclopentadienyl rings are
aromatic – each containing 6 delocalized π
electrons like benzene.
6.
7. Cyclopentadiene undergoes a 4+2
cycloaddition to formdicyclopentadiene. For
this reason, cyclopentadiene is usually
purified before use. Dicyclopentadiene boils
at 170°C and cyclopentadiene boils at 42.5°C.
For efficiency, the dicyclopentadiene dimer is
thermally cracked using a fractional
distillation apparatus. KOH should be grind in
a mortar and quickly transfer it to a tared vial.
8. KOH is hygroscopic and should be ground in
small portions (2 g).KOH chemical need to be
in dry state. The finely
groundedFeCl2.4H2O will also go into solution
more effectively. It is then placed in a tared
vial. The pre-weighed KOH (15 g) is placed in
a 100 mL (14/20) three-neck round bottom
flask equipped with a magnetic stirring bar.
9. 1,2-Dimethoxyethane (30 mL) is added with
stirring to the KOH. One side of the neck is
stoppered and the other is connected to a
vacuum line through a gas adapter. While the
mixture is slowly stirred and the flask is
being purged with a stream of nitrogen, then
2.75 mL amount of cyclopentadiene is added.
The resulting solution which is formed is in
rose color.
10. The main neck is then fitted with a pressure
equalizing dropping funnel which is labeled
as 25 mL with its stopcock open. After fitting
of stopcock to the flask second neck round
bottom flask that is fitted with a
septum,FeCl2.4H2O (3.25 g) and DMSO (12.5
mL) are stirred under a nitrogen atmosphere
to dissolve the FeCl2.4H2O
11. By finishing above procedure, next step should
start after about five minutes. The stopcock is
closed and then FeCl2 solution is added to the
pressure equalizing dropping funnel.
The reaction mixture in the three-neck flask is
stirred vigorously and the purging with nitrogen
is continued.
After about ten minutes, the stopper is placed on
the dropping funnel, the nitrogen flow is reduced
and drop-by-drop addition of the FeCl2 solution
is begun.The rate of addition is adjusted so that
the entire solution is added in 30 minutes.
12. Then the dropping funnel stopcock is closed and
vigorous stirring of the dark green solution is
continued for an additional 30 minutes.
Finally, the nitrogen flow is stopped and the
mixture is added to a mixture of 45 mL 6M
HCl and 50g of crushed ice.
Some of the resulting slurry may be used to rinse
the reaction flask to maximize the product yield.
The slurry is stirred for about 15 minutes and the
orange precipitate is collected on a Buchner or
Hirsch funnel and washed with four 5-mL
portions of water.
13. The moist solid is spread out on a large
watch glass and dried in the air.
The compound is then purified through
sublimation in a large glass petri dish that is
placed on a warm hot plate (100°C).Certain
precautionary precedures are required to
avoid charring the ferrocene.
The purified ferrocene is then characterized
by melting point determination, UV-Vis and
IR spectroscopies, and cyclic voltammetry.
14. It is used as a catalyst for the production of
carbon nanotubes
Ferrocene’s derivatives are antiknock agents
and also used as fuel for petrol engines.
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