Sciencemadness Discussion Board

Synthesis of Creatininium Tetrachlorocuprate

h0lx - 13-9-2020 at 14:51

I have recently been a bit hooked on tetrachlorocuprates and trying to make them with all sorts of cations to varying success.

Multiple failures have gone towards using creatinine as a cation, most of them due to probably my first batch of creatinine not being properly converted and the rest by accidentally overheating and producing tar. Yesterday I finally managed to make, what I believe to be (creat)2(CuCl4), since I wasnt able to find any info on this compound online, decided to share, what I found here, and the second successful upscaled synthesis as my first post in the last 13 years.

Also a large thanks to Austin and Henry, who took their time to proofread this.

Proposed structure:


Preparation:
In a 50 ml beaker, 6 g (40 mmol) of Creatinine Hydrochloride was dissolved in minimal amount of distilled water (about 20 ml) with constant mechanical stirring. Once the solution clarified, 3.4 g (20 mmol) of solid CuCl2 x 2H2O was added into it, and the resulting solution carefully heated with constant stirring, to reduce some volume, while taking care not to overheat it. The solution colour progressed through the following colours: light blue, light green, dark green, almost opaque black. When the solution was about half of it's original volume, it was transferred to a shallow dish to evaporate and slowly dried at 80°C with constant airflow. The resulting dark tar-like solid was then collected and transferred to a beaker to which ~50 ml acetone was added, a stir bar was dropped in and the contents stirred vigorously for about 2 minutes followed by a filtration, where a vivid green solid was collected and lightly orange colour of the filtrate was noted(This proves that a reaction had occurred, since otherwise most CuCl2 would dissolve, leaving a dark brown opaque solution, this was verified by a control)


[Edited on 13-9-2020 by h0lx]

DraconicAcid - 13-9-2020 at 14:58

You don't think the creatine might coordinate to the copper?

h0lx - 13-9-2020 at 15:00

That happens, when its not protonated, but that coordination complex is quite blue in solution and yields a pale teal product. I doubt it's the case here.

MidLifeChemist - 13-9-2020 at 17:03

The compound is quite beautiful

DraconicAcid - 13-9-2020 at 17:23

Quote: Originally posted by h0lx  
That happens, when its not protonated, but that coordination complex is quite blue in solution and yields a pale teal product. I doubt it's the case here.


Even when it's protonated, you've got two lone pairs on B that could easily coordinate. If you didn't have any coordination to copper, it'd be yellow like (NR4)2CuCl4.

h0lx - 13-9-2020 at 17:30

What's NR4? also green is also the colour of say BaCuCl4, and theres no coordination to copper other than the tetrachlorocuprate anion.

DraconicAcid - 13-9-2020 at 18:06

Quote: Originally posted by h0lx  
What's NR4? also green is also the colour of say BaCuCl4, and theres no coordination to copper other than the tetrachlorocuprate anion.


Tetraalkylammonium cation. Tetraethylammonium tetrachlorocuprate is yellow.

h0lx - 13-9-2020 at 20:21

Hmm, that's interesting. Tbh apart from some crystallography I cant think of a way how to find out if it really is what I set out to make.

Bedlasky - 13-9-2020 at 22:51

Quote: Originally posted by DraconicAcid  
Quote: Originally posted by h0lx  
What's NR4? also green is also the colour of say BaCuCl4, and theres no coordination to copper other than the tetrachlorocuprate anion.


Tetraalkylammonium cation. Tetraethylammonium tetrachlorocuprate is yellow.


Cs2[CuCl4] is also yellow.

h0lx - 15-9-2020 at 04:23

An update, it seems to grow crystals quite well, as my in progress rex of the compound demonstrates:



[Edited on 15-9-2020 by h0lx]

valeg96 - 19-9-2020 at 09:22

Sorry if I'm being late here. During my pedantic home chemistry activities I've made a couple creatinine complexes, so I'll provide you with some of the literature I have found (all experimental stuff, I don't save any theoretical studies unless truly useful).

Experimental information on creatininium tetrachlorocuprate, including x-ray structures, are found in Udupa 1979
Other creatinine-Cu complexes have been prepared by Materazzi 1999, including the tetrachlorocuprate.
More amusing creatinine complexes are those listed by Muralidharan 1989 that involve Co halides and are amazingly colorful.
A rather large family of creatinine Ni complexes was made by Materazzi 1999 (another article).
Creatinine forms a wide variety of complexes, and I can provide more information if you want to attempt it with other metals.

A great and stable tetrachlorocuprate complex is the one with thiamine, which I made according to Marzotto 1970, which was published in a pretty secretive journal. If you're interested send me a message and I'll help you source it.

Lastly, just a friendly reminder that creatinine can be easily produced from creatine, which is much cheaper and available in bulk as sport supplement, without heating or charring (just what the hell did you do? Lol)

Edit: looking at your post history, glad to see you're finally posting something not "energetic materials" related for your first post in 13 years; I hope that phase is over, lol.

[Edited on 19-9-2020 by valeg96]

[Edited on 20-9-2020 by valeg96]

h0lx - 1-10-2020 at 18:08

Wow thanks! That's exactly what I was looking for on it, but failed to find! I will print those papers all out tomorrow at work! That is very helpful. I stumbled on this complex while trying different cations for the tetrachlorocuprates, since I have been interested in them lately. I also successfully made K2CuCl4, NaCuCl4, (NH4)2CuCl4, BaCuCl4 and (urea)2CuCl4. I definitely will try the other things there as well.
Quote: Originally posted by valeg96  

Lastly, just a friendly reminder that creatinine can be easily produced from creatine, which is much cheaper and available in bulk as sport supplement, without heating or charring (just what the hell did you do? Lol)

Yeah, thanks, I did make both reagents myself, creatinine HCl was done by a prep suggested by a friend, where creatine was slowly boiled to dryness in excess HCl. CuCl2 was just made from CuSO4 via the basic carbonate
Quote: Originally posted by valeg96  

Edit: looking at your post history, glad to see you're finally posting something not "energetic materials" related for your first post in 13 years; I hope that phase is over, lol.

I think so yes, in that period I have stopped the chemistry hobby, grown up, and started it again. Energetics become boring once you grow up :P

EDIT: made another batch yesterday to investigate it more, took some pictures:
https://imgur.com/gallery/mbkzmhq

[Edited on 2-10-2020 by h0lx]

valeg96 - 2-10-2020 at 05:10

Creatinine can be made in a very clean way without charring or boiling to dryness. I can fetch the procedure I used, if you want. It's along those lines but I got a quantitative result. Now that I think about it, I could check with an NMR if it's as pure as it looks.

valeg96 - 2-10-2020 at 05:12

Also, before slamming everything in the oven I would personally try adding a couple drops of acetone, ethanol, isopropanol or ether to a small sample of solution. You'd be surprised to see how many complexes can be isolated by just adding alcohol or acetone to their aqueous solution.

h0lx - 2-10-2020 at 06:08

I would like to see it sure, might make it even easier :)

My current one got only a slight yellow tinge in any case:
nsTJg2es.png.jpg - 2kB

DraconicAcid - 2-10-2020 at 16:08

Quote: Originally posted by h0lx  
I also successfully made K2CuCl4, NaCuCl4, (NH4)2CuCl4, BaCuCl4 and (urea)2CuCl4.


How did you manage those? The literature preps that I've tried for the potassium and ammonium salts did not work at all, and I'd like to try again.

h0lx - 2-10-2020 at 16:23

For both of them: take 2:1 molar ratio of NH4Cl/KCl:CuCl2, dissolve in water and evaporate dry.

A drop or two of HCl supposedly helps em along, but apparently not required.

Best to dissolve in minimal water, boil down a bit and leave to stand on a shelf for a week or so.

Those 2 look the same too pretty much visually.


[Edited on 3-10-2020 by h0lx]



[Edited on 3-10-2020 by h0lx]

DraconicAcid - 2-10-2020 at 17:25

Oh, yes, those. Sorry, I was thinking of KCuCl3 and NH4CuCl3, which are supposed to be intense red. Synapse gap on my part.

h0lx - 2-10-2020 at 17:37

Can CuCl3 even exist out of solution?

DraconicAcid - 2-10-2020 at 17:45

[CuCl3]- apparently does.

valeg96 - 5-10-2020 at 10:14

So, I prepared my creatinine with a method adapted by Edgar 1923.

The first step is condensation of creatine. The second step is the production of the free base.

10 g creatine are gently boiled with 10 mL HCl 32% in a stirred beaker with a watch glass (or refluxed) for 2 h. The pasty white mixture is then covered with some parafilm and with vigorous stirring, 7 mL of conc. ammonia are added with a syringe, and stirred for about 15' to break the crusty mass. The mixture is cooled in a fridge for 2 h, filtered on a G3 Gooch, washed with 10 mL conc. ammonia, 30 mL EtOH, 10 mL acetone and dried in a desiccator for 12 h. The yield is quantitative, and the product is around 80% creatinine and 20% ammonium chloride. The ammonium chloride content can probably be reduced by not cooling the mixture in the fridge before filtering on the gooch, and washing it a bit more (but not too much!)

[Edited on 5-10-2020 by valeg96]

DraconicAcid - 6-1-2024 at 10:58

Quote: Originally posted by h0lx  
For both of them: take 2:1 molar ratio of NH4Cl/KCl:CuCl2, dissolve in water and evaporate dry.

A drop or two of HCl supposedly helps em along, but apparently not required.

Best to dissolve in minimal water, boil down a bit and leave to stand on a shelf for a week or so.

Those 2 look the same too pretty much visually.


[Edited on 3-10-2020 by h0lx]



[Edited on 3-10-2020 by h0lx]

Sorry for re-awakening an old thread, but how do you isolate the crystals of K2CuCl4? They seem to decompose if I try washing them with alcohol.