Sciencemadness Discussion Board - Beta-Alanine amino acid copper salt

Beta-Alanine amino acid copper salt

Lion850 - 16-2-2021 at 20:36

After reading that most of the common amino acids form complexes with many transition metals I wanted to make some to see the colors. And the first is is an almost perfect blue!

There is not a lot of basic info about these reactions readily available online. Beta-Alanine powder (eBay) and copper carbonate (pottery supply) was used to make a copper salt.

I assumed the following reaction for the stoichiometry - is this correct?
CuCO3 + 2C4H7NO4 = Cu(C4H6NO4)2 + CO2 + H2O

- 21.5g alanine powder was dissolved in 120g water. It dissolved very easily, solubility as reported on Wikipedia seems incorrect or maybe my food grade alanine is a hydrate.
- 10.1g copper carbonate was slowly added to a warm solution while stirring. A gentle reaction was observed, with bubbles being generated.
- The solution was stirred hot for some one hour.
- After an hour the solution was dark blue and there see to be no more solid carbonate left. It was then gravity filtered.
- The filtrate was a lovely deep blue liquid, and there was a very small amount of remainder, I assume unreacted carbonate.
- It was left to cool overnight, the next day at room temp there was no crystals.
- The solution was boiled down to under 50ml, still no crystals. It was then placed in an evaporating dish on a steam bath.

- After MANY hours on the steam bath the weight was constant, some solid was visible, but it was not losing weight any more. It just stayed wet. At this point the contents of the dish was approximately 38g.

- Scratch all into a big beaker and add 150ml methanol. Boil and stir for 30 minutes. Let the ppt settle, decant, add methanol again and boil and stir. Note the decanted supernatant methanol was purple in color.
- Vacuum filter and rinse with methanol in filter. The remainder was blue damp crystalline solid.

- Dry on steam bath until weight constant.
- 19.8g of lovely blue dry product recovered. This is a yield of about 75%.

The color was a nice surprise, the purest blue of the copper compounds I had made. It is very soluble in water.

Cobalt is in progress and I also want to try nickel.

[Edited on 17-2-2021 by Lion850]

Texium - 16-2-2021 at 21:21

Worth noting: this is beta alanine you used, not alanine. In other words, the amine is attached the beta carbon rather than the alpha carbon, like it would be in “regular” alanine, so your thread title is a bit misleading.

The equation that you stated looks fine to me other than the copper carbonate not being written as basic copper carbonate. Since basic copper carbonate also contains some hydroxyl groups your ratios will be a bit off if you go with CuCO₃ as an approximation. It’s probably not enough to make a difference, but I would be interested to see you try it again with a more ideal ratio to see if it’s still the same color. An excess of alanine could make the color appear more blue than it should be, by giving the copper more amines to coordinate with.

The structure of this complex is probably rather, well, complex. The dark blue color is from the amine groups coordinating to the copper ions, in the same way that the dark blue ammine complexes form with ammonia. So the copper ions are balancing the charge of the carboxylates while also being coordinated with the amines.

Lion850 - 16-2-2021 at 22:10

Hi Texium thanks for the comments! Title now edited. I know the alpha and beta have something to do with left and right handedness (beyond my understanding); does it have any effect on the appearance of subsequent compounds?

Bedlasky - 16-2-2021 at 22:36

Quote: Originally posted by Lion850

I know the alpha and beta have something to do with left and right handedness (beyond my understanding)

Alpha means that substituent (in your case NH2 group) is bonded through the first carbon next to COOH. Beta means that substituent is bonded through the second carbon next to COOH. Similary with gamma, delta, epsilon etc.

Lefthanded isomers have L in their name (like L-fructose, L-alanine, L-serine etc.)

Righthanded isomers have D in their name (like D-glucose, D-mannose etc.)

Anyway, very nice looking compound.

Lion850 - 16-2-2021 at 22:58

Thanks Bedlasky! In practise does it make a difference to the chemistry and physical appearance of compounds?

Bedlasky - 17-2-2021 at 00:30

Of course.

https://en.wikipedia.org/wiki/Chirality_(chemistry)

vano - 17-2-2021 at 00:59

Nice work, thanks for sharing. Chirality makes quite a difference. For example thalidomide. One isomer(R) is used during toxicosis, but second one(S) is teratogen like mercury and PCBs.

Texium - 17-2-2021 at 08:39

Chirality only effects chemical properties with respect to other chiral molecules, such as biological receptors. Thus it can affect smell, taste, and drug effects, but it will not change the physical appearance or the general chemical properties at all.

Beta alanine is not chiral, because the amine group is on the terminal carbon, which can rotate freely. Alpha amino acids (except glycine) are all chiral because the amine can either be on the “front” or “back” of the molecule, and those molecules would be non-superimposable mirror images, no matter how you twist them around. As Bedlasky alluded to, (alpha) alanine would have two stereoisomers, indicated as L-alanine and D-alanine. Since beta alanine is not chiral, it has no such designations.

[Edited on 2-17-2021 by Texium (zts16)]

njl - 17-2-2021 at 11:02

I'm not sure if chirality is the right term, but that type of isomerism can actually effect reactions with non-chiral reagents. For example, some cis-diols will form ketals while their trans counterparts will not (can't remember where I read this but if I find the ref I'll link it).

Texium - 17-2-2021 at 12:37

Quote: Originally posted by njl

I'm not sure if chirality is the right term, but that type of isomerism can actually effect reactions with non-chiral reagents. For example, some cis-diols will form ketals while their trans counterparts will not (can't remember where I read this but if I find the ref I'll link it).

That's a more complex topic. Any carbon atom with four unique substituents is considered a stereocenter or chiral center because switching the positions of any two groups connected to it will result in a non-superimposable structure. If a molecule only has one stereocenter, such as alanine, then it is automatically considered chiral, and inversion of it will result in its enantiomer, which would have the same physical and chemical properties, unless they are in a chiral environment. If a molecule has more than one stereocenter, such as your diols, then there are multiple possibilities. Let's look at 2,3-butanediol.

As you can see, there are three different stereoisomers. Two are a chiral pair (a pair of enantiomers) and would have identical properties in a non-chiral environment. This is because BOTH of the stereocenters are inverted. If you only change one of the stereocenters, you end up with the third stereoisomer. It is a special case known as a meso compound because it is not chiral (doesn't have an enantiomer). A stereoisomer that is not an enantiomer is called a diastereomer. Diastereomers do differ in their chemical properties, sometimes very significantly. So the meso compound is considered to be a diastereomer of each of the other two isomers.

Lion850 - 17-2-2021 at 17:39

Gents thanks for the explanations.

I need to confess....I used the wrong formula for Alanine in my original post and in my stoichiometry

I used the formula for Aspartic acid (C4H7NO4) instead of Alanine (C3H7NO2). I think the correct formula for the reaction is:

CuCO3 + 2C3H7NO2 = Cu(C3H6NO2)2 + CO2 + H2O

This means there were excess alanine in the solution, assuming it it not a hydrate. I'm not sure what happened to this excess; after the first filtering stage there was a very small remainder but I assumed that was unreacted carbonate. When the product dried on the steam bath there was no sign of 2 separate salts: usually if it is a mix one will fall out during steam bath drying before the other and often shows up as a different colored ring in the evaporating dish.

The excess may also have mostly ended up in the purple filtrate when filtering off the methanol. I wished now I boiled this filtrate down to see what was in it but unfortunately it was discarded.

Texium - 17-2-2021 at 19:17

You wouldn’t have seen two separate salts because what you likely have is the copper salt of beta alanine with additional beta alanine (that isn’t deprotonated) coordinated to each copper ion. It wouldn’t be a hydrate because the alanine is a stronger ligand and would displace the water molecules.

Bedlasky - 17-2-2021 at 22:36

Here is some literature to copper(II)-beta alanine complexes.

https://sci-hub.se/https://pubs.acs.org/doi/10.1021/ja01043a...

Texium - 18-2-2021 at 07:22

Interesting, so according to that paper it looks like the complex that forms with excess beta alanine present is [Cu(β-Ala)₃(H₂O)₂]^-

vano - 18-2-2021 at 09:01

I want to make cobalt taurine salt. Will the metal bind to the amine group and water molecules? Because there are more oxygen on sulfur. Will it not prevent?

Texium - 18-2-2021 at 14:24

Sulfonic acids are terrible ligands: worse than carboxylic acids. If you reacted cobalt carbonate with taurine, yes, the sulfonic acid would be deprotonated and you'd have the cobalt salt, but as far as how the ions would arrange themselves, well, amines are much more strongly coordinating than sulfonic acids, so you'd likely have a structure with the amine nitrogens coordinated to the cobalt ions and the sulfonic acids sticking out further away. Also worth noting that cobalt(II) amine complexes are quite easy to oxidize to their corresponding cobalt(III) complexes. You can do it with moderately concentrated hydrogen peroxide. You should give it a try.

vano - 19-2-2021 at 00:12

Quote: Originally posted by Texium (zts16)

Sulfonic acids are terrible ligands: worse than carboxylic acids. If you reacted cobalt carbonate with taurine, yes, the sulfonic acid would be deprotonated and you'd have the cobalt salt, but as far as how the ions would arrange themselves, well, amines are much more strongly coordinating than sulfonic acids, so you'd likely have a structure with the amine nitrogens coordinated to the cobalt ions and the sulfonic acids sticking out further away. Also worth noting that cobalt(II) amine complexes are quite easy to oxidize to their corresponding cobalt(III) complexes. You can do it with moderately concentrated hydrogen peroxide. You should give it a try.

Thank you so much. Can you give me 2 and 3 complexes structures?

Bedlasky - 19-2-2021 at 01:41

This is best what I found. It doesn't tell you anything about structures, but at least about basic formula and stability of these complexes:

https://core.ac.uk/download/pdf/207493218.pdf

vano - 19-2-2021 at 02:02

thanks. I have already downloaded this file. From what I saw I downloaded everything but the structure was nowhere to be found. Neither sci-hub could help me

Texium - 19-2-2021 at 09:27

Without a crystal structure, knowing the exact structure of the complex with certainty isn't really possible, but cobalt in either oxidation state typically forms octahedral complexes with amines, so my hypothesis is that you would end up with something along these lines if you start from cobalt(II) carbonate:

H₄[Co(Tau)₆] for cobalt(II)
and
H₃[Co(Tau)₆] for cobalt(III)

You could also try obtaining the alkali metal salt of the complex ion by partially neutralizing the taurine before reacting it with your cobalt carbonate. Whatever the exact structure may be, with an excess of taurine, you will likely have six taurines coordinated to each cobalt ion through the amine nitrogens. I doubt that the sulfonates would be good enough ligands to displace any amines from the first coordination sphere.

Keep in mind that I am not an expert in inorganic chemistry by any means, and these conjectures are based on a limited, mostly academic understanding of how this stuff works.

vano - 21-2-2021 at 04:52

Thanks. Today i bought 4% solution of taurine and i will try some complexes.

Lion850 - 2-3-2021 at 11:11

I've been struggling to get a dry-ish chromium B-alanine salt. I tried some 4 or 5 different ways up to now; a violet colored product salt is the common result. But it is very hygroscopic and worse it forms a sticky mess with water, methanol, and glacial acetic acid. Still ongoing and I will eventually post all the details.

zed - 7-3-2021 at 10:19

Hmmmm. This isn't entirely related, but somewhere I glimpsed a reference that inferred, complexing with copper may provide some "Protection" for Amino-Acids.

Can these complexes, act as "protecting groups" in some circumstances? Sequestering Amino-groups, away from undesirable suitors?

Lion850 - 7-3-2021 at 11:28

Chromium:
I spent hours trying to get a reasonably dry Chromium B-alanine complex. I wont detail all the attempts as it will be pages but some observations:
- The fact that something with a violet color forms is a common link between all the attempts.
- Cr(OH)3 boiled with b-alanine for some 12 hours seems to yield 2 products: a grey insoluble ppt and a violet very soluble product that seems to have a low melting point, turns more white on the steam bath, but once cooled slowly becomes violet again. Photo further down. But there also always seems to be unreacted Cr(OH)3 left over.
- B-alanine with Cr(NO3)3 boiled - no obvious reaction.
- B-alanine boiled in water with chromium acetate in (I am not sure of the formula; it can be various) yield vinegar smelling fumes and a very dark (beautiful) purple syrup which is near impossible to get a dry salt from. This syrup boils at near 120C so my usual solution of boiling it out in toluene don't work as toluene has a lower bp (I dont have xylene at the moment). This purple product is quite soluble in methanol. One attempt involved boiling on the steam bath until the sticky syrup did not lose weight any more, then dissolving in methanol in batches and pouring the methanol solution into boiling toluene. My hope being that the methanol would boil off leaving the product as a powder in the toluene. This worked to an extent as I got some crystals; I left them to dry and then next morning they were a wet sticky mess - its also quite hygroscopic.
- Adding b-alanine to NaOH to produce the sodium complex and then adding a chromium iii chloride to this immediately produces a black ppt. And.....the filtrate is violet!
- I also found very little info about chromium b-alanine complexes online which does not help with working out stoichiometry. So I ran some experiments a few times with different ratios.

Chromium hydroxide and b-alanine at the start of the experiment.

Hydroxide and b-alanine after some 12 hours boiling and then left overnight to settle. Green unreacted hydroxide, very fine grey suspensded powder, and violet supernatant solution.

The hydroxide reaction filtrate.

The salt extracted from the hydroxide filtrate.

The black salt that ppt out when b-alanine was first reacted with NaOH and then with CrCl3.

The dark purple thick liquid from reacting chromium acetate and b-alanine and many, many hours on the steam bath.

Trying to boil out the above in toluene - it forms a sticky plasticky mess! But some (violet) crystals can be seen in the bottom of the beaker.

S.C. Wack - 7-3-2021 at 11:52

Gmelin's

Lion850 - 7-3-2021 at 11:52

Batch test:
30g NaOH was dissolved in 100g water and 75g b-alanine was then added. This quickly dissolved complete giving a clear solution which was then made up to 200g by adding a bit more water. Assuming the product of the reaction is C3H6NO2Na then the alanine was in slight access and I should have ended up with 8g sodium-alanine in every 20g of solution.

20g portions of this solution was then mixed with solution containing about 5g of each of the below salts to see what happens and if anything produces a salt interesting enough to extract.

1) Cobalt ii nitrate - a pink-ish ppt was formed.

2) Copper sulphate - a very dark blue fine suspension, similar to the first post above.

3) Erbium iii bromide - a pale pink jelly ppt.

4) Iron iii nitrate - a brown ppt.

5) Iron ii sulphate - a grey ppt.

6) Manganese ii nitrate - a very pale pink ppt.

7) Nickel ii nitrate yielded a copious amount of a lovely blue ppt. I filtered this off and rinsed it with water.

The color paled a bit after it dried on the bench:

8) Praseodymium iii nitrate gave a green jelly.

9) Titanium iii chloride was interesting: Once mixed the solution started to bubble. The gas produced had no smell. It also heated up slightly. Eventually there was a white-ish suspension left which I assume is TiO2?

Bezaleel - 7-3-2021 at 14:49

The black and red-purple chromium salts are really special. I would expect them to have Cr and b-alanine in different proportions. Did you do any tests on those compounds? It's a pity that S.C. Wack's excerpt from Gmelin's doesn't seem to mention anything about the colours of the complexes.

The blue nickel salt is gorgeous! Quite special to see nickel adopt a type of blue like that. I made nickel citrate last week, but the colour is a regular bluish green, like we know from other nickel compounds. It became a syrup which slowly dried up to a hard layer.

Besides, you would really do me a favour if you would rotate the pictures so that the beakers do not show horizontally. To me it makes looking at those pictures so much easier. Having said that, I always enjoy reading your posts.

S.C. Wack - 7-3-2021 at 15:52

Quote: Originally posted by Bezaleel

Gmelin's doesn't seem to mention anything about the colours of the complexes.

Except where it says red, violet, dark green, and green...BTW that was from part C, presumably also where the relevant section on Cu would be if it was one of the 183 volumes scanned by Springer...sale ends tomorrow on 719 volumes, $4 shipping.

DraconicAcid - 7-3-2021 at 16:02

Nickel is usually blue when it has both N-bound and O-bound ligands in an octahedral arrangement (if it just has O-bound ligands, then it's almost always green, and if it just has N-bound ligands then it's generally purple). Tris(glycinato)nickel is that kind of blue, although I've never been able to get it out of solution.

The chromium complex(es) may be complicated. Chromium(III) isn't labile, so you're likely to have different isomers even assuming you have the same Cr-alanine ratio. Cis, trans, fac, mer.....lots of fun.

Lion850 - 7-3-2021 at 20:12

Hi DraconicAcid I now hold the phone sideways and select ‘square’ seemed to have worked with the last post. The only things I can say about the chromium b alanine is that it is very soluble in water, reasonably soluble in methanol and easily makes a sticky mess if chromium acetate is involved as a starting material. Also was more white after the steam bath but then returned to violet standing on the bench overnight.

I would like to do chromium again starting from chromium carbonate - I tried to make some but it was a mess of jelly.

Bezaleel - 8-3-2021 at 03:57

Quote: Originally posted by S.C. Wack

Quote: Originally posted by Bezaleel

Gmelin's doesn't seem to mention anything about the colours of the complexes.

"Das nach Eindampfen auf dem Wasserbad erhaltene glasartige rote Rk.-Prod."
"Der gebildete, violette kristalline Nd."

I must have been really tired....

Quote: Originally posted by DraconicAcid

Nickel is usually blue when it has both N-bound and O-bound ligands in an octahedral arrangement (if it just has O-bound ligands, then it's almost always green, and if it just has N-bound ligands then it's generally purple). Tris(glycinato)nickel is that kind of blue, although I've never been able to get it out of solution.

Thanks for that piece of insight

Quote: Originally posted by Lion850

Hi DraconicAcid I now hold the phone sideways and select ‘square’ seemed to have worked with the last post.

Great!

Quote: Originally posted by Lion850

The only things I can say about the chromium b alanine is that it is very soluble in water, reasonably soluble in methanol and easily makes a sticky mess if chromium acetate is involved as a starting material.

I got a sticky foaming mess dissolving SrCO3 in dilute acetic acid. It could be that acetate tends to make the liquid viscous.

Quote: Originally posted by Lion850

I would like to do chromium again starting from chromium carbonate - I tried to make some but it was a mess of jelly.

I made Cr-carbonate a few years back and it formed a very voluminous precipitate. Suction filtration and washing took al long time. It was not sticky, just voluminous, but I made it from the chloride, not the acetate.

vano - 8-3-2021 at 06:12

Quote: Originally posted by Lion850

.

9) Titanium iii chloride was interesting: Once mixed the solution started to bubble. The gas produced had no smell. It also heated up slightly. Eventually there was a white-ish suspension left which I assume is TiO2?

I do not know why but I do not have titanium compounds. Will you make other titanium compounds in the future? For example Cobalt (II) orthotitanate. It has beautiful dark green colour, aslo there are many beautiful compounds which you will like. I hope i try in the future

Bedlasky - 8-3-2021 at 06:40

Lion850: TiCl3 is quite unstable, you must store it under inert atmosphere. Gas evolving from solution is hydrogen. You must dissolve it in HCl and not in water, because in water Ti(OH)3 is formed and this compound is very unstable and decompose in very very short time.

Btw. it is better to make fresh TiCl3 solution before using than making and storing solid.

vano - 8-3-2021 at 08:06

I agree with Bedlasky. No problem if it from chemical company, but i think Homemade will be contaminated. This is easy to identify, just the color will not be appropriate.

[Edited on 8-3-2021 by vano]

Bezaleel - 8-3-2021 at 09:42

Quote: Originally posted by Bedlasky

Lion850: TiCl3 is quite unstable, you must store it under inert atmosphere. Gas evolving from solution is hydrogen. You must dissolve it in HCl and not in water, because in water Ti(OH)3 is formed and this compound is very unstable and decompose in very very short time.

Btw. it is better to make fresh TiCl3 solution before using than making and storing solid.

But how do you do that? Ti dissolves extremely slowly in whatever concentration of HCl you use.

vano - 8-3-2021 at 09:49

Quote: Originally posted by Bezaleel

But how do you do that? Ti dissolves extremely slowly in whatever concentration of HCl you use.

The best way to dissolve titanium is hydrofluoric acid. I think he used titanium dioxide. It dissolves in concentrated hot hydrochloric acid at 90°C, but I'm sure the product will not be pure.

Bedlasky - 8-3-2021 at 10:40

Quote: Originally posted by Bezaleel

But how do you do that? Ti dissolves extremely slowly in whatever concentration of HCl you use.

I use titanium powder which dissolves quite well in concentrated hydrochloric acid. I don't need it often, so I bought just the smallest 100g bottle for 5,75€. I know that you can buy titanium cheaper, but if you work in small scale, it is better to invest in to powder, you save yourself lots of time with disolution.

Quote: Originally posted by vano

The best way to dissolve titanium is hydrofluoric acid. I think he used titanium dioxide. It dissolves in concentrated hot hydrochloric acid at 90°C, but I'm sure the product will not be pure.

You need strong reducing agent for reduction Ti(IV) to Ti(III), HCl is just weak reductor.

[Edited on 8-3-2021 by Bedlasky]

Lion850 - 8-3-2021 at 11:12

Quote: Originally posted by vano

I think he used titanium dioxide. It dissolves in concentrated hot hydrochloric acid at 90°C, but I'm sure the product will not be pure.

Vano my report on making TiCl3 is here:

http://www.sciencemadness.org/talk/viewthread.php?tid=12981&...

As stated in the report i used titanium powder and it dissolved in HCl without too much difficulty. But for sure the end product is not pure. And it has now been sitting in the bottle for nearly a year.

vano - 8-3-2021 at 11:58

Lion850: nice, thanks.

Bedlasky: I do not know why I made this simple mistake. Of course you are right.

Lion850 - 9-3-2021 at 01:19

The erbium b-alanine salt mention in the batch test post above was filtered off and washed in the funnel and dried on the steam bath. I half expected the colour to fade during drying but they retained the pink nicely.

Lion850 - 25-4-2022 at 22:41

Quote: Originally posted by vano

Thanks. Today i bought 4% solution of taurine and i will try some complexes.

Hi Vano - how did you go with the taurine?

Dmishin - 31-5-2022 at 13:13

Just want to revive this topic and show my humble finds.
First photo is a crystal of copper beta-alaninate. It is apparently a hydrate, exposed to air, it dehydrates rather quickly.
Second and third show crystals of cpper beta-alaninate urea adduct. Obtained by crystallizing a solution, containing copper beta-alaninate and urea in 1:2 molar ratio.
Crystals have different form and do not dehydrate in dry air!

DraconicAcid - 31-5-2022 at 13:33

Wow!