Thank you very much. What happens to the bromide substiuent?TeethWhitener said:
I’ve honestly never really thought about it before. I imagine the hydride binds to the bromine, pushing the electron pair from the Co-Br bond onto the cobalt center. So you’ll get HBr out, but these reactions are often done under slightly alkaline conditions, so it’ll probably be bromide ion at the end.Mayhem said:
Yes, the NaBH4 is stabilized in KOH as the solvent is MeOH in this case. I turned in the assignment the other night, so I guess we will just wait and see.TeethWhitener said:
Eh, these were pre-lab safety schemes. I didn't consider it homework in the traditional sense.TeethWhitener said:
The purpose of NaBH4 in this coboxalamine alkylation is to act as a reducing agent. It is used to reduce the cobalt (III) ions to cobalt (II) ions, which are necessary for the alkylation reaction to occur.
NaBH4 is a strong reducing agent due to its ability to donate hydrogen atoms. In this reaction, it donates a hydrogen atom to the cobalt (III) ions, causing them to be reduced to cobalt (II) ions. This reduction allows for the alkylation reaction to take place.
NaBH4 is chosen as the reducing agent in this reaction because it is highly reactive and selective. It only reduces the cobalt (III) ions and does not react with other components in the reaction mixture, making it a suitable choice for this specific reaction.
In addition to its role as a reducing agent, NaBH4 also acts as a source of hydride ions, which are necessary for the alkylation reaction to occur. It also helps to stabilize the cobalt (II) ions formed during the reduction process.
One potential side reaction that can occur is the over-reduction of the cobalt (III) ions to cobalt (I) ions. This can be minimized by carefully controlling the amount of NaBH4 used. Additionally, NaBH4 may not be suitable for reactions that require a milder reducing agent.