Sciencemadness Discussion Board

Cu(III) EDTA complex

bismuthate - 2-9-2014 at 12:14

I believe I've created a Cu(III) complex with EDTA.
IT is synthesized by mixing solutions of tetrasodium EDTA, CuSO4, and Na2S2O8. In my most recent trial I mixed .3g CuSO4, 2g Na2S2O8, and 3g tetrasodium EDTA in 75mL of water. I then heated it for about 2 min (not timed) with a butane burner. Here is a small amount of the final solution. https://www.dropbox.com/sh/9k285acviex2q5o/AACCFlyttO6ier6YS...
I did notice small amounts of brown precipitate which may be copper oxide.

thesmug - 2-9-2014 at 13:07

Are you talking about a chelate or some other type of complex? EDTA chelates most metals really well. Seems like a fun procedure and looks cool too.

bismuthate - 2-9-2014 at 13:13

To be honest I couldn't find any literature on the subject so I believe it may be a new complex ion, but I believe it is a chelate complex.

(If this is a new ion that will sound good on a resume:))

bismuthate - 3-9-2014 at 13:47

Ok so I'm just gonna say this straight forward.First: Do you believe this is a new complex I can't say what it is has anybody heard about something like this?
Second: To be honest I've never really discovered anything and don't know how to go about this if this is new. Any advice on what to do then?

kmno4 - 3-9-2014 at 14:19

Try to add to your mixture 1 g NaCl, 0,382g NiSO4, 5,01g Pb(NO3)2 and 1 cm3 of red wine.
I belive that you will discover another complex, maybe Cu(IX) or more probably Cu(XII).
I also belive that you should produce more interesting posts of this kind.
We belive in you, Master of Complexes.

The Volatile Chemist - 3-9-2014 at 14:23

Looks like you have been doing a good job so far! In regards to your first question, I don't know. There are a lot of sulfur-oxygen ion complexes that are hard to predict/account for. Eg. try reacting Sodium thiosulfate w/ Ferric Ammonium, or ferrous ammonium sulfate. Try the reaction w/o the EDTA (No offense if you already have done this). It could be this is just a sulfur-oxygen ion complex. [Have you read http://en.wikipedia.org/wiki/Copper#Copper.28III.29_and_copp... ? Read the little section to the end, it has some things on Cu(III) complexing.]
So, I don't know if this is new or not, but even if it isn't, it's new to home chemistry.

In regards to your second statement, be persistent in figuring out the EXACTNESS of the reaction. Play everything that could happen around in your mind, then test for all the possibilities. I'd take about a week to think on all the info you have. Don't be disappointing if it isn't what it seems. If it has been 'discovered', you may still have a found a new route to making it. Regardless, have fun with the discovery and testing process. I really don't know much about the actual process of submission of ideas.

-TVC, Nathan


UH...
Quote: Originally posted by kmno4  
Try to add to your mixture 1 g NaCl, 0,382g NiSO4, 5,01g Pb(NO3)2 and 1 cm3 of red wine.
I belive that you will discover another complex, maybe Cu(IX) or more probably Cu(XII).
I also belive that you should produce more interesting posts of this kind.
We belive in you, Master of Complexes.


Kmno4, why the insults? If you think an experiment is unscientific, or unscientifically based, post constructively. We both know Bismuthate isn't a kewl or kook or quiche eater, so you aught to be understanding that not everyone works in the same ways. (Sorry if this is not what you're going for)

[Edited on 9-3-2014 by The Volatile Chemist]

Brain&Force - 3-9-2014 at 15:03

This has a striking similarity to something Tdep did when he made tetraammine copper(II) persulfate. The stuff decomposes to form a green solid.

<iframe sandbox width="560" height="315" src="//www.youtube.com/embed/mNdkNzncrMY" frameborder="0" allowfullscreen></iframe>

Perhaps you have made a mixture containing copper(II) edtate and a persulfato complex of copper(II). Check here: http://woelen.homescience.net/science/chem/exps/CuIII/index....

[edit] as soon as I get to university I'll ask a professor if I can research this and the decomposition product of TACP.

[Edited on 3.9.2014 by Brain&Force]

bismuthate - 3-9-2014 at 15:08

kmno4: It would be more helpful if you explained what you disliked about my experiment.
The Volatile Chemist: No EDTA means no reaction for the experiments I've done. (also I hate the thiosulfate Fe+3 reaction when i tried to film it it would only work when my camera was pointed away.)
I've been thinking this over and testing the whole summer (although I was away for a lot of the time) and this it the only explanation I can think of. From what I've seen EDTA can help metals reach higher oxidation states e.g. cobalt, manganese.

To be honest I don't quite know what the reaction occurring is so I can't find exact amounts (thus my odd measurements).

bismuthate - 3-9-2014 at 16:13

Oh oops brain&force i didn't see your post. The problem is I can't get the green without persulfate and I can't get it without EDTA and neither of those reactions have both. Although the analysis of the green solid left behind by the decomposition of tetraaminecopper(II) persulfate sounds really cool.

Brain&Force - 3-9-2014 at 20:34

Have you considered that potentially, the persulfate is oxidizing EDTA to something causing a green chelate?

woelen - 4-9-2014 at 08:51

I think that the green complex still is a copper(II) complex. Brain&Force may be right. Another thing may be that the persulfate decomposes, giving O2 and HSO4(-) ions in water and the acidity of the solution may change the properties of EDTA so that a complex is formed.

Green is not an unusual color for copper(II) complexes. If the color were deep red, then I would be convinced more. I made a complex of periodate and copper and this is deep red and forms very dark red crystals.

unionised - 4-9-2014 at 10:28

How have you ruled out the reaction predicted by looking in a chemistry textbook?
Peroxide will convert tertiary amines to their oxides.
That oxide may well form a complex with Cu++.

bismuthate - 4-9-2014 at 13:12

woelen: i don't think that the persulfate decomposes because the reaction will sill occur after just siting out for a day.
To everboy else; Well I know just about nothing on inorganic chemistry so I can't say anything.