benzylchloride1
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Some experiments in organometallic chemistry
I have an interest in organometallic chemistry and I recently conducted the synthesis of cyclopentadienyl iron carbonyl dimer at the university I
attend. Here is my write up of the experiment. I hope this encourages more forum members to conduct experiments in organometallic chemistry.
Introduction
The chemistry of transition metal carbonyls has lead to many important discoveries in chemistry such as homogenous catalysts, fuel additives, useful
synthetic intermediates and the study of carbonyl compounds has lead to a better understanding of chemical bonding itself.
Cyclopentadienyl(dicarbonyl)Iron dimer is an example of a transition metal carbonyl complex. This experiment involves the reaction of iron
pentacarbonyl, a liquid organometallic compound with cyclopentadiene generated by refluxing dicyclopentadiene with iron pentacarbonyl under an inert
atmosphere. The product is then obtained as reddish-violet colored crystals that are air stable. Most organometallic chemistry involves compounds that
are slightly to highly air sensitive. The product of this experiment is not air sensitive, but the iron pentacarbonyl and the reaction mixture at
reflux temperature are moderately air sensitive.
This experiment introduces the use of air free techniques for the preparation of the desired compound. Air sensitive experiments require attention to
detail at all times in order to isolate a satisfactory product. Many air sensitive compounds are pyrophoric, which means that they can be
spontaneously flammable in air. If the temperature of the reaction mixture is not carefully controlled, finely divided iron powder will be formed from
the decomposition of the iron pentacarbonyl at high temperatures. The finely divided iron powder can spontaneously inflame when drying the product by
drawing air through it when filtering.
Cyclopentadienyl(dicarbonyl)Iron dimer has many interesting structural and chemical properties. This compound has a metal to metal bond, bridging
carbonyl, terminal carbonyl ligands and pentahapto cyclopentadienyl ligands. The compound prepared in this experiment exists as 3 isomer forms in
solution which inter convert between the 3 forms. Molecules that exhibit this property are called fluxional compounds. This compound is a useful
chemical intermediate; halogens cleave the metal to metal bond to form the corresponding halides. These halides can then be reacted with Grignard
reagents to produce the corresponding iron alkyl compounds. Cyclopentadienyl(dicarbonyl)Iron dimer can be reduced to form the corresponding ion;
(C5H5)Fe(CO)- which can then be reacted iodomethane to form cyclopentadienyl(dicarbonyl)methyl iron.
1. 2Fe(CO)5 + C10H12 = (C5H5)2Fe2(CO)4 + 6CO +H2
2. (C5H5)2Fe2(CO)4 +2NaBH4 +CH3I =(C5H5)Fe(CO)2CH3
Safety Information Pertaining to this Experiment
All chemicals used in this experiment are severely toxic. Dicyclopentadiene is a toxic, flammable liquid with a very bad oily odor. This compound
should only be used in a fume hood while wearing gloves. Iron pentacarbonyl is deadly poisonous and air sensitive. This compound must only be handled
in a fume hood while handling gloves. The compound is very volatile and produces deadly poisonous carbon monoxide gas and pyrophoric iron powder upon
heating. The iron pentacarbonyl is stored under a positive pressure of carbon monoxide which must be vented in a fume hood before transferring the
compound via syringe and needle to the reaction flask. Bromine water which is used to decontaminate glassware that has contacted iron pentacarbonyl
and the waste liquid obtained from the reaction must be handled in the hood with gloves because of its toxic and highly corrosive nature. All metal
carbonyl complexes are considered toxic and should be handled with care; this includes the Cyclopentadienyl(dicarbonyl)Iron dimer product produced in
this experiment. Iodomethane is highly toxic and a known carcinogen; exercise extreme care when handling this compound, wear gloves and handle only in
a fume hood while wearing gloves. Exercise care when filtering the final product and avoid drawing air through it in case pyrophoric iron powder was
produced due to less then careful temperature control during the refluxing of the reactants. Vacuum lines can be dangerous if mishandled. Use common
sense and wear safety goggles at all times when working in the chemistry laboratory.
Procedure
1. Synthesis of Cyclopentadienyl(dicarbonyl)Iron dimer
All steps of this synthesis were carried out in a fume hood equipped with a vacuum line. An apparatus consisting of a 250 ml 3-neck 24/40 flask,
mercury thermometer with a proper 24/40 adaptor, 24/40 condenser, septum and a nitrogen gas inlet positioned at the top of the condenser was
assembled. The flask was flushed with nitrogen for several minutes. A heating mantle controlled with a themowatch calibrated to maintain the reaction
at 135 degrees Celsius was used to heat the reaction mixture. 64 ml of dicyclopentadiene was measured out with a graduated cylinder and poured into
the reaction flask. 10 ml (14.6g) of iron pentacarbonyl was drawn out of its reagent bottle with a 10 ml syringe and needle after venting the excess
carbon monoxide pressure. The iron pentacarbonyl was than injected into to the reaction mixture through the septum. The inert gas source was removed
and a mineral oil bubbler was attached. Water was run through the condenser and the mixture was then heated to 135 degrees Celsius and maintained at
that temperature with a thermowatch for 16 hours before shutting off the heating. Exceeding 140 degrees promotes the decomposition of the iron
pentacarbonyl with the formation of pyrophoric iron powder. Below 130 degrees no reaction occurs. It is critical to keep the temperature around 135
degrees during the entire reaction. The reaction was run over night with proper precautions regarding temperature control and the rubber hoses
supplying water to the condenser were wired in place. All glassware that contacted iron pentacarbonyl was washed with bromine water in the fume hood.
The reaction apparatus was disassembled and the mineral oil in the bubbler was treated with bromine water. The dark colored reaction mixture was then
vacuum filtered with a fritted funnel. The reddish-purple crystals of the product were then washed with 4-20ml portions of low boiling petroleum ether
to remove excess dicyclopentadiene. The product was then transferred using a spatula and a funnel to a small Schlenk flask. A dry ice-acetone bath was
prepared and used to chill the trap on the vacuum line. The vacuum pump was turned on and the vacuum line was purged with nitrogen. The Schlenk flask
containing the product was then connected to the vacuum line and put under vacuum for 30 minutes to remove remaining solvent. Care must be taken to
prevent the contamination of the vacuum line with the product during this operation. The flask was taken off the vacuum line and the product was
transferred to a tared vial. The product weighed 7.86g for a percentage yield of 60%.
2. Attempted Synthesis of cyclopentadienyl(dicarbonyl)methyl iron.
All steps of this synthesis were conducted in a fume hood equipped with a vacuum line. A 100ml 3-neck flask was equipped with a reflux condenser,
septum, magnetic stir bar, gas inlet and a gas outlet connected to a mineral oil bubbler. The flask was purged with nitrogen. 1.0g of the
Cyclopentadienyl(dicarbonyl)Iron dimer was placed in the flask. 20 ml of dry tetrahydrofuran was then added to the flask. The mixture was heated to
reflux under a nitrogen atmosphere. 0.1g of finely powdered sodium borohydride was mixed with 20ml of tetrahydrofuran and added to the mixture by
removing the septum. The septum was then put back on the neck of the flask. The mixture was then slowly cooled over a period of 30 minutes with
stirring. 1ml of iodomethane was then injected through the septum using a syringe and needle. The mixture was then stirred for 10 minutes. The vacuum
line was set up as in the previous synthesis using a dry ice-acetone bath to cool the trap to prevent volatile materials from entering the vacuum pump
oil. The tetrahydrofuran solvent was then removed using the vacuum line. After the solvent was removed, an attempt was made at subliming the product
into the reflux condenser using a heat gun was made while the apparatus was still under vacuum. No product sublimed into the condenser. Violet colored
crystals of the starting product coated the bottom of the flask. A very small amount of orange, waxy material was apparent on the wall of the flask.
This could have been some of the product. No product was obtained due to the lack of a suitable cold finger condenser that could be used for the
sublimation of the product.
Experimental Data for this Experiment
Compound Grams Obtained Theoretical Yield Percentage Yield
(C5H5)2Fe2(CO)4 7.86g 13.2g 60%
(C5H5)Fe(CO)2CH3 NA 0.93g 0%
Calculations and Results
Theoretical yield of Cyclopentadienyl(dicarbonyl)Iron dimer: 13.2g
14.6g Fe(CO)5 1 Mole Fe(CO)5 1 Mole (C5H5)2Fe2(CO)4 353.8g (C5H5)2Fe2(CO)4
195.9g Fe(CO)5 2 Mole Fe(CO)5 1Mole (C5H5)2Fe2(CO)4
Percentage yield of Cyclopentadienyl(dicarbonyl)Iron dimer: 60%
Theoretical Yield of Cyclopentadienyl(dicarbonyl)methyliron: 0.93g
1.0g (C5H5)2Fe2(CO)4 1 Mole (C5H5)2Fe2(CO)4 2 Mole 163.9g (C5H5)Fe(CO)2CH3
353.8g (C5H5)2Fe2(CO)4 1 Mole 1Mole (C5H5)Fe(CO)2CH3
Percentage Yield of Cyclopentadienyl(dicarbonyl)methyliron: 0%
Discussion
This experiment illustrates synthesis and handling of air sensitive materials. The synthesis of the Cyclopentadienyl(dicarbonyl)Iron dimer worked
extremely well and the product was obtained as a reddish-purple crystalline flakes. A modest yield of the desired compound was obtained. The product
was not recrystallized due to the good appearance of the crystals. The procedure for the synthesis of the cyclopentadienyl(dicarbonyl)methyliron was
adapted from the literature because of the limited amount of reagents available. The procedure in Synthesis and Technique in Inorganic Chemistry
called for a solution of triethyl potassium borohydride in tetrahydrofuran. This was not available, so sodium borohydride was substituted instead. The
sodium borohydride was almost insoluble in the tetrahydrofuran. Very little of the waxy-orange colored product was found in the reaction flask. The
proper cold finger sublimation condenser was not available, so the product could not be sublimed from the reaction by products. Much reddish violet
crystalline residue was apparent in the reaction flask which indicated that the reduction did not proceed properly. The lack of reduction could have
been due to the insolubility of sodium borohydride in tetrahydrofuran or the reducing properties of this reagent.
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benzylchloride1
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Here are some organometallic compounds that I synthesized in my home lab.
Bis-mesitylene Iron (II) Perchlorate
2.5g of anhydrous iron chloride was placed in a 200ml Schlenk flask. 30ml of heptane distilled from automotive starter fluid was then added. A
magnetic stirrbar was then added. 3.43g of anhydrous aluminum chloride and .14g of aluminum powder was then added; the mixture was stirred during the
process. 3.9g of mesitylene prepared by the method in Organic Syntheses from acetone and sulfuric acid was then added. A reflux condenser with a
calcium chloride drying tube was then attached. The mixture was heated to reflux with vigerous stirring for 2 hours. The mixture turned black in color
during the reflux. The mixture was allowed to cool to room temperature and the solvent was decanted from the dark colored reaction product. A slurry
of 10g of ammonium perchlorate in 30ml of water was then added in small portions very carefully with rapid swirling. A pale tan colored solid formed.
Material that adheared to the walls of the flask was loosened with a glass stirring rod. The mixture was swirled until all of the black colored
aluminum chloride complex had disapeered. The product was then filtered off, rinsed with water and then washed with methanol. After drying over night,
the compound weighed 2.7g. The percentage yield was 45%. Adapted from Inorganic Experiments, VCH Publishers.
Ferrocene
10ml of cyclopentadiene was freshly cracked from dicyclopentadiene, collecting the fraction below 40 Celsius. 20ml of dimethylsulfoxide was degassed
with argon
in a 250ml rbf. 5.0g of ferrous chloride tetrahydrate was placed in the flask containing the DMSO and swirrled over a period of about 20 minutes to
dissolve the compound completely. 20g of potassium hydroxide was finely powdered and added to 50ml of diethyl ether in a 250ml 3-neck flask. A
condenser and addition funnel were connected to the flask. The flask containing the KOH and ether was flushed with argon. 10ml of dicylopentadiene was
then added. The mixture turned brown from the formation of potassium cyclopentadienide. The Kcp was heavily contaminated with oxygen which was
indicated by the brown color. The mixture was magnetically stirred for 1/2 hour. The solution of iron (II) chloride in DMSO was then slowly added
through the addition funnel. The reaction mixture darkened in color. The solution was stirred for a further 1/2 hour to complete the reaction. 100ml
of 6M HCl was then slowly added. The mixture was then poured into a seperatory funnel. The organic layer was orange in color, while the aqueous layer
was gray-blue in color. The organic layer was decanted and the aqueous layer was further extracted with ether. The organic layer was dried over
anhydrous MgSO4 and filtered into a 500ml rbf. The solvent was removed using a rotary evaporator. Upon cooling, orange crystals of ferrocene formed.
The crystals were filtered off and the solvent was allowed to evaporate at room temperature from the crystals. The product weighed 2.1g and melted at
171 Celsius. The percentage yield was 44%. Adapted from Inorganic Experiments, VCH Publishers.
[Edited on 12-4-2009 by benzylchloride1]
Tetraethyltin
15g of magnesium powder was placed in a 250ml 3-neck flask. 45ml of diethyl ether was distilled from starter fluid using a solvent still. A magnetic
stirr bar ws added to the flask and a reflux condenser with a drying tube was added. A addition funnel was attached and a glass stopper was used to
close the 3-neck of the flask. 10ml of bromoethane, prepared from ethanol, NaBr and H2SO4, was added along with the 45ml of freshly distilled diethyl
ether. A vigerous reaction ensued. 43ml of bromoethane was then added through the additon funnel slowly. After the refluxing from the initial
reaction had ceased, 39g of tin(IV) bromide , anhydrous, dissolved in 30ml of heptane. The SnBr4 solution was placed in the addition funnel and slowly
added to the solution of ethyl magnesium bromide in ether. A white additon complex formed. The mixture was then allowed to stand for several hours.
20ml of ice water was then slowly added, along with 100ml of 6M HCl was then slowly added. The product was extracted with ether and the black colored
colloidal tin removed from the etherial extract by filtration. The solution of tetraethyl tin was then allowed to stand over anhydrous MgSO4 over
night. The solution was filtered into a 250ml rbf and the solvent removed with a rotary evaporator. The residual liquid was then distilled under
reduced pressure using a water aspirator. The fraction boiling between 80-85 Celsius was collected. The tetraethyl tin was obtained as an extremely
unpleasant, pungent smelling liquid. This organotin compound is considered highly toxic. Handle only in a fume hood. The smell was noticed when
cleaning the glassware used in the synthesis. The tetraethyl tin weighed 10.1g and was obtained with a 48% yield. The tin (IV) bromide used in the
experiment was prepared by reacting dry bromine with mossy tin and distilling the mixture. The product solidifies in the condenser.
[Edited on 12-4-2009 by benzylchloride1]
[Edited on 12-4-2009 by benzylchloride1]
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chemrox
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Polverone: could we please have an organometallic forum?
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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bfesser
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Pretty please?
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Polverone
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Is there enough activity to justify a separate forum? A few years back I saw a small spurt of activity with computational chemistry and created the
Computational Models and Techniques section, but now I feel a bit foolish for having created it.
PGP Key and corresponding e-mail address
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DJF90
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Being interested in organic chemistry, A forum on organometallics would be incredably good indeed. However I cant help but feel it will become
overcrowded by threads on the bazillion and one metal complexes out there, which personally bring no excitement.
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benzylchloride1
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Here are some more experiments that I conducted at the university in organometallic chemistry. My current primary research interest is in
organometallic chemistry and I have been conducting many experiments in the area at home and at the university. Currently there is not enough activity
on Sciencemadness for a seperate forum on this area, but a thread on the topic is warrented.
The synthesis of nickelocene
Nickelocene is an interesting air sensitive organometallic compound that is very dark green in color. Its reactive nature stems from the fact that it
has 20 electrons and will react with many reagents to form an 18 electron ion.
Experimental:
40ml of tetrahydrofuran was distilled from sodium benzophenone ketyl. Sodium benzophenone ketyl removes the last traces of water and oygen from
solvents and is very dark blue in color. Exposure to air causes the color to instantly vanish due to its reaction with atmospheric oxygen.
Dicyclopentadiene was cracked to cyclopentadiene by heating 50 ml of dicylopentadiene in a 500ml rbf and collecting the fraction boiling below 40
Celsius. Use an fractionating column and you will not have contamination with the dimer. A stir bar was placed in a 500mL 3-neck flask, along with a
reflux condenser, rubber septum and a gas inlet and outlet connected to a mineral oil bubbler. The flask was purged with argon for several minutes.
The 40ml of THF was transferred via cannula into the reaction flask. The septum was briefly removed and 1.0g of sodium hydride was added, the septum
was replaced and the magnetic stirrer was started. 7.0ml of cylopentadiene was slowly injected into the suspension of sodium hydride. Much hydrogen
gas was produced and the solution turned to a purple color due to the formation of sodium cyclopentadienide. The color was much better then that of
the potassium cyclopentadienide used in the previous synthesis of ferrocene due to proper air free techniques. The solution was stirred for 10 minutes
and then cooled in an ice bath. 3.5g of hexamine nickel(II) chloride was then added and the ice bath removed. The solution at this point was light
purple in color. The mixture was heated to barely below the reflux temperature of tetrahydrofuran over a peroid of 1 hour. The mixture turned to a
very dark green color due to the formation of nickelocene. The solvent was removed under vacuum and the nickelocene was sublimed using a cold finger
condenser under vacuum, while heating the flask in an 80 Celsius water bath. The dark green nickelocene was scraped off the condenser with a spatula
and sealed in a glass ampule. A melting point was determined; the nickelocene melted at 170 degrees Celsius. The product weighed 1.02g and the
percentage yield based on the nickel salt used was 36%.
Acetyl Ferrocene
Experimental:
6.0g of ferrocene was placed in a 50ml rbf with a stirbar. 20ml of acetic anhydride was added and a reflux condenser was attached. The mixture was
stirred until all of the ferrocene had dissolved. 4.0ml of 85% phosphoric acid was then added through the top of the condenser. The solution turned
dark red in color and heated up. The solution was heated for 10 minutes with a magnetic stirring hot plate just below the reflux point of acetic
anhydride. The reaction mixture was then poured into a 1000ml beaker that was 1/5 full of ice with rapid stirring. 140ml of a 10% sodium hydroxide
solution was then added. The crude orange colored product was then suction filtered and washed with water. The product was dried by pulling air
through the filter and pressing the solid. The product was then placed in a 250ml flask with 80ml of hexanes and brought to a boil. The orange colored
solution was then decanted from dark colored polymeric material. The solution was then boiled with decolorizing charcoal and filtered. The solution
was concentrated with a rotary evaporator until crystals formed and cooled in an ice bath to complete the crystallization. The product was filtered
off and the mother liquer concentrated to obtain a second crop of crystals. The product obtained was recrystallized from hexane and filtered. The dark
red colored acetylferrocene obtained melted at 85 degrees Celsius and weighed 4.1 grams. The percentage yield was 55%.
[Edited on 13-4-2009 by benzylchloride1]
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Nicodem
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Nice work benzylchloride1!
Though, I do have a little suggestion for you... do you mind attaching some schemes to make the thread a bit more exciting. It is hard for the
beginners to understand what these compounds are, and a few reaction schemes would make it look better.
----- off topic -----
We already have an Organic chemistry section. Besides if all you three had to contribute to this topic was some off topic posting, then it would
really be irrational to open another forum section just for cosmetic reasons. In all forums I have ever seen, more sections meant just less quality
posting.
Quote: Originally posted by Polverone  | | A few years back I saw a small spurt of activity with computational chemistry and created the Computational Models and Techniques section, but now I
feel a bit foolish for having created it. |
I don't think that was a bad idea. Even though up to now we did not have a single proper thread opened on the topic of computational chemistry in that
section, I think this might change sooner or later. There are probably not many members using Linux, and even less such that are able to learn such
complex programs like Gaussian or Schrodinger package, not to even mention the theory behind it, but I think it is good to have a home for anybody
that ever manages to get up to such a level as an amateur (where even trained chemists fail!). But I'm surprised none of the so many members
interested in drugs is interested in learning at least to use Autodock or other (relatively easy to use) medicinal chemistry software, the
results of which could be posted in that section.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Sedit
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Just a few papers I found of mine while going thru them benzyl that I thought you or anyone else interested may find useful.
The Organometallic Chemistry Of Transition Metals
http://www.thevespiary.org/sedit/MISC/The%20Organometallic%2...
http://www.thevespiary.org/sedit/MISC/Organometallics.pdf
http://www.thevespiary.org/sedit/Chemistry%20-%20Organic/Syn...
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Klute
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I thought I could post a few preparations of organometallic precursors, things I've done lately at work. Hope this can interest people.
Synthesis of [Pd0(dba)2]
I. Synthesis of dibenzylideneacetone
In a 500mL single neck RBF, sodium hydroxyde (13.47 g, 337 mmol, 5.5 eq) was dissolved in a mixture of water (115 mL) and ethanol (90 mL). After
cooling back to room temperature, a mixture of benzaldehyde (13 g, 122,5 mmol, 2 eq) and acetone (3.56 g, 61 mmol, 1 eq) was slowly dripped
in during 10 min with vigorous stirring. The reaction mixture turned slowly limpid yellow, then suddenly turbid, and 10 minutes after the end of the
addition, a yellow solid gradually precipitated, giving a thick yellow slurry. Stirring was continued for another 2h at room temperature, after which
the slurry was filtered, the solids generously washed with water (100 mL) and dried at 60°C. The bright yellow solid was then recrystallized from
ethyl acetate and pentane, filtered, washed with pentane, and air dried. The collected solid weighed 11.425 g (48.82 mmol), 80.04 % yield, and was pur
by TLC (eluant: 75:25 CH2Cl2:cyclohexane)
Reference:
Organic Syntheses, Coll. Vol. 2, p.167 (1943);
II. Synthesis of bis(dibenzylideneacetone)palladium
In a 500mL schlenk, dibenzylideneacetone (4.60 g, 19.6 mmol, 3.3 eq) and sodium acetate (6.47 g, 78.9 mmol, 13.3 eq) are dissolved in distilled
methanol (250 mL) at 40-50°C. To the limpid yellow solution obtained is added palladium chloride (1.05 g, 5.9 mmol, 1 eq), immediatly forming a dark
brown suspension, and the mixture is heated to 40°C for 4h. The suspension turns dark purple/black. The solids are filtered over a fine glass fritt,
washed with water (70 mL) and acetone (70 mL), then briefly air dried. The dark brown/purple solid is transfered to a small schlenk and dried under
vacuum. The dried product weighs 3.34 g (5.81 mmol), 98.47 % yield.
Ref: Synthetic Pages 53 (2001) Link
Preparation of Ir2Cl2(COD)2
2.0g of iridium trichloride hydrate were dissolved into 34mL of ethanol and 17mL of water in a 3 neck 100mL RBF with a nitrogen inlet and a
condenser. 6.0mL of 1,5-cyclooctadiene (COD) were then added via syringe, and the light orange mixture heated to reflux for 24H.
A biphasic mixture was obtained, with a dark orange heaby oil, which was extracted with 3x25mL DCM, dried with MgSO4, and the solvent evaporated.
30mL of ether was added to the dark brown oil obtained, which caused an immediate precipitation. The solid was filtered on a glass fritt, washed with
2x10mL ether, and drie dunder vacuum. The dark red solid collected weighed 1.498g (72% yield).
ref: Inorganic Syntheses; 15, 18 (1974)
[Edited on 15-5-2009 by Klute]
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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len1
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Interesting. Are the organometalics being used for something at your work, or is this just an interest?
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Klute
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Yes, indeed they are being used. The Pd(dba)2 for Suzuki couplings and other applications where Pd0 is required, and the Iridium complex used for
ligand exchanges.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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benzylchloride1
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Klute; thank you for posting these syntheses.
I wish that I had some palladium and iridium salts. Many of their organometallic compounds are extremely useful in organic synthesis, but are very
expensive. I am thinking about synthesizing bis(dibenzylideneacetone)nickel from nickel chloride and dibenzylideneacetone which is easy to synthesize
from artificial almond extract which is a solution of benzaldehyde in ethanol. Dibromobis(triphenylphosphine)nickel(II) can be used in cross coupling
reactions between alkyl halides and Grignard reagnets. This complex is very easy to make; add a solution of nickel (II) chloride hexahydrate in
anhydrous 2-propanol to a refluxing solution of triphenylphosphine in 2-propanol. Allow to cool, filter and dry. I have used 91% 2-propanol, the
complex will not crystallize unless the water is azeotropically distilled out of the mixture with toluene.
Here are the structures of the compounds that I synthesized:
[Edited on 15-5-2009 by benzylchloride1]
[Edited on 15-5-2009 by benzylchloride1]
[Edited on 15-5-2009 by benzylchloride1]
[Edited on 15-5-2009 by benzylchloride1]
[Edited on 15-5-2009 by benzylchloride1]
Attachment: Organometallic compounds.skc (12kB)
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Amateur NMR spectroscopist
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