Sciencemadness Discussion Board

Mn(Cl)2 vs Mn(Acetate)2 with a salen ligand(ethylenediamine+salicylaldehyde)

Tiago Gomes - 10-11-2004 at 09:04

I´m an undergratuate studente and i´m doing several complexes, one of them is Mn with a salen ligand ((bis(salicylaldehyde)ethylenediamine)) and i need Mn(acetate)2 but i only have Mn(Cl)2.
Is it possible?? is the Cl a goog exit group for this reaction???Any thoughts on this??
(rebember the complex has the metal coordenated with the ligand and, afterwards i´m putting a Cl atom attatched to the metal(reaction of the ligand with KCl))

I am a fish - 10-11-2004 at 10:50

Why not turn the MnCl2 into Mn(CH3COO)2?

Convert MnCl2(aq) into MnCO3 by precipitation with Na2CO3(aq), and then dissolve this in CH3COOH.

guaguanco - 11-11-2004 at 08:50

Quote:
Originally posted by Tiago Gomes
I´m an undergratuate studente and i´m doing several complexes, one of them is Mn with a salen ligand

Unless I'm missing something:
1) either Mg(CH3COO)2 or MgCl2 is going to completely dissassociate in water solution.
2) You're creating the coordination complex
(Ligand)MgCl2, where the ligand occupies 4 of the 6 coordination sites.
3) Using MgCl2 is actually easier, since the chloride ion is already provided for you.

unionised - 12-11-2004 at 07:38

IIRC you are missing the fact that the salen loses a couple of hydrogens (from the phenolic OHs) and forms a salt with the Mn.
Using an acetate buffer might do the job but converting the chloride to acetate is easy, so that's probably what I would do.
(edit) And converting the acetate to chloride gives you another half a page of reprt without much work.

[Edited on 12-11-2004 by unionised]

Tiago Gomes - 13-11-2004 at 13:21

thanks for all the replies, but i´´m not allowed do do another reaction to convert the MnCl2 to Mn(acetate)2 and i have to use MnCl2 it´s stupid i know don´t ask why!!(teatcher problems aka stupidity) thks anyway, so maybie i will use Mgcl and try it

in reply do guanguaco 4 sites are ocupied by the ligand and only one by Cl treatting the complex with KCl salen MgCl

( here´s the article: http://www.biochemj.org/bj/366/0097/bj3660097.htm#CITE20 )

another topic : is the copper(salen), rather than the Mn(salen) a better catalyst for oxidation of carbon-corbon double bonds (styrene) with iodosobenzene?? (i know that Mn is but don´t know why)

do you know any bibliography or internet sites where i can find some info on this???

[Edited on 13-11-2004 by Tiago Gomes]

[Edited on 13-11-2004 by Tiago Gomes]

svm - 14-11-2004 at 10:05

I guess it's not too pertinent at the moment, but a very simple way to convert MnCl2 to Mn(acetate)2 is by treating with silver acetate and then filtering off the AgCl precipitate.