Organometallic Reactions Help

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In summary, the products of the following reactions are:(a) biphenyl mercury and MgCl2(b) dimethyl bis(triphenylphosphine) palladium and methyl aluminum dibromide(c) TlF3 and BMe3(d) possibly a mix of cis and trans-but-2-ene.
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rmjmu507
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Homework Statement



What would be the products of the following reactions?

(a) Phenylmercuric Chloride and phenylmagnesium chloride
(b) bromo methyl bis(triethylphosphine)palladium and dimethyl aluminum bromide
(c) dimethyl thallium fluoride and difluoro methyl boron
(d) bromo methyl bis(triethylphosphine)palladium and trans-but-2-ene

2. The attempt at a solution

(a) I believe the products would be biphenyl mercury and MgCl2, as the mercury-bound phenyl is more reactive

(b) I really do not know...dimethyl bis(triphenylphosphine) palladium and methyl aluminum bromide?

(c) I believe the products would be TlF3 and BMe3...Tl is more electropositive, so it will want to bond to form halides.

(d) Again, I really do not know. I assume the alkene would coordinate to the palladium center, but after this I can't say.
 
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To first order, this is an exercise in comparing reduction potentials of various metals in these exchange reactions.

rmjmu507 said:
(a) I believe the products would be biphenyl mercury and MgCl2, as the mercury-bound phenyl is more reactive
The right answer for the wrong reason. In fact, the reasoning is almost the opposite of what you have. Mg has a more negative reduction potential than Hg, so MgCl2 will be more stable than HgCl2.

rmjmu507 said:
(b) I really do not know...dimethyl bis(triphenylphosphine) palladium and methyl aluminum bromide?
Methyl aluminum dibromide, yes. Aluminum has the lower reduction potential, so the halogens prefer to be on it instead of the palladium. (EDIT: really, the aluminum side will want to go all the way to AlBr3 if it can do so stoichiometrically. I imagine you'd see a mixture of the two compounds)

rmjmu507 said:
(c) I believe the products would be TlF3 and BMe3...Tl is more electropositive, so it will want to bond to form halides.
I'm pretty sure this is fine. You don't hear much about organothallium compounds. But as a general rule, transition metal organics will react with boron trihalides to give the organoboron compounds (this is, in fact, how most organoboron compounds are made commercially).

rmjmu507 said:
(d) Again, I really do not know. I assume the alkene would coordinate to the palladium center, but after this I can't say.
This one's a weird one. It looks a lot like the Heck reaction, but I'm not used to seeing the Heck reaction on internal alkenes. If the mechanism follows the Heck reaction, the only thing I can think is that maybe it isomerizes trans-2-butene to a mix of cis and trans. I'm just not sure about this one, and a quick internet search brings up nothing about exchange reactions in palladium methyl bromo compounds (though they are used like other Pd organometallics in cross coupling catalysis).
 

1. What are organometallic reactions?

Organometallic reactions are chemical reactions that involve the interaction of organic compounds with metal-containing compounds. These reactions typically involve the breaking and forming of covalent bonds between carbon and a metal, and can be used to synthesize a variety of organic molecules.

2. What is the mechanism of organometallic reactions?

The mechanism of organometallic reactions involves the coordination of a metal atom or ion with the organic compound, followed by the breaking of a metal-carbon bond and the formation of a new metal-carbon bond. This mechanism can vary depending on the specific reaction and the type of metal involved.

3. What are some common applications of organometallic reactions?

Organometallic reactions have a wide range of applications in organic synthesis, including the production of pharmaceuticals, agrochemicals, and materials. They are also used in catalysis, where the metal catalyst can speed up the rate of a chemical reaction.

4. What factors influence the reactivity of organometallic compounds?

The reactivity of organometallic compounds can be influenced by several factors, including the type of metal, the nature of the organic ligand, and the reaction conditions (e.g. temperature, solvent). In general, metals with lower electronegativities and larger atomic radii tend to be more reactive.

5. What are some common challenges in conducting organometallic reactions?

Organometallic reactions can be challenging due to the air and moisture sensitivity of many organometallic compounds. This requires strict handling techniques and the use of specialized equipment. Additionally, some reactions may require the use of toxic or expensive reagents, making them more difficult to carry out on a large scale.

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