Sciencemadness Discussion Board

Organometallic Chemistry Ideas?

ssdd - 10-5-2011 at 12:58

Hi all,

Inspired by some recent experiments I was hoping to play around with some more organometallic chemistry.

I was wondering if anyone knows of any good synthesis that yields an interesting organometallic compound. Preferably I would like to stay with common metals (iron, nickel, tin, zinc, etc etc, though I do have access to a small amount of Pt) and avoid any overly complex reactions (5-8 steps max).

Thanks for the input!
Tim - ssdd

DJF90 - 10-5-2011 at 13:56

I'm assuming that you have a Schlenk line and the appropriate glassware that most organometallics synthesis requires. You should look at the 4 attached files - they're pages I photocopied from a book last time I was at the library (http://www.amazon.co.uk/Advanced-Practical-Inorganic-Metalor...).

Organometallics is a hard branch of chemistry to break into due to the air and moisture sensitive manipulations it often requires. Some very simple Organometallics are inaccessible to most people due to the requirement of certain materials, such as the metal carbonyls (Fe(CO)5, Cr(CO)6 etc) and some ligands (Cp and Cp* (although the latter can be made), acac etc). You may wish to check the volumes of Inorganic Syntheses, as there are frequently preparations in there. A good initial preparation for you would be Chromium (II) acetate, which features a Cr-Cr quadruple bond (sigma, 2x pi and delta) and is fairly simple (as far as organometallics go).

The best of luck to you!

Attachment: Advanced Practical Organometallics 1.pdf (398kB)
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Attachment: Advanced Practical Organometallics 2.pdf (156kB)
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Attachment: Advanced Practical Organometallics 3.pdf (100kB)
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Attachment: Advanced Practical Organometallics 4.pdf (144kB)
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[Edited on 10-5-2011 by DJF90]

ssdd - 10-5-2011 at 14:49

Thanks DJF90! The PDFs look informative, I'll be sure to give them a good read!

I am lucky in the sense that I have an entire organic chemistry lab at my disposal and a boss that will let me play around on the side (I work part time in our schools science building when I'm not there for labs).

Chromium (II) acetate looks extremely easy to make, I will likely give this a try some time soon. (I'll have to figure out a good way to purify it free of air...)

Tim - ssdd

DJF90 - 10-5-2011 at 15:04

Check out Inorganic Syntheses - theres a chromium acetate prep in there. I'm sure you could find more procedures online if you look.

BromicAcid - 10-5-2011 at 15:07

Related thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=2677

Cr(II)Acetate

ssdd - 12-5-2011 at 09:37

Yesterday I successfully made some Chromium(II)Acetate, a very simple synthesis!

I used a synthesis found online, this synthesis used an interesting setup which reduced the Chromium in a side arm test tube, and then used the pressure of the hydrogen gas produced to push the Chromium solution into a beaker of sodium acetate... Heres a pic of the setup: followed by one of the reagents:



The mossy zinc reacting with HCl to reduce the chromium:


Final Product formation:



The yield was very good, but sadly i lost some product due to a defective filter...

Tim -ssdd

plante1999 - 13-5-2011 at 16:22

Chromium II acetate is definitly the best organometalic/coordination experiment to do , prety simple but it need to be donne with all glass setup (frited glass filter) and use conssentred sol. ad a silica gel pack to keep the compound dry in an vial.

DJF90 - 13-5-2011 at 17:35

I find it pleasing that you had success with this experiment. Any ideas what you're going to do next?

ssdd - 14-5-2011 at 15:15

Yea, I'm glad the experiment worked out, it was a fun/colorful synthesis!

As to what I'm going to try next I'm not sure, theres some dry ice in out -80 freezer that needs used, so perhaps a cloud chamber while I find another fun organometallic synthesis...

Any good ideas for other synthesis?

Tim - ssdd

Melgar - 16-5-2011 at 20:02

Hmm, Grignard reactions are interesting and very useful. Not sure if you have magnesium and diethyl ether, but if you do, the possibilities are pretty limitless.

http://en.wikipedia.org/wiki/Grignard_reaction

The Barbier reaction is supposedly less sensitive, so may be easier if you have the proper chemicals:

http://en.wikipedia.org/wiki/Barbier_reaction

Panache - 16-5-2011 at 22:02

Lead(IV) Acetate from Brauer works as described and worked the first time i tried it, dunno if this is strictly an organo metallic though. i haven't tried it sans acetic anhydride though although apparently the procedure with only glacial acetic acid does work as described, another author referenced it AFAIK. You can then make some tetraethyl lead and drive your car really fast

ScienceSquirrel - 17-5-2011 at 03:15

You really do not want to make tetraethyl lead.

DJF90 - 17-5-2011 at 03:38

To be honest, the chromium acetate preparation isnt organometallic chemistry, due to the lack of a fundamental Metal-Carbon bond. However, it appears you enjoyed it all the same; as such, may I suggest you go deeper into the field of complex chemistry - you'll certainly encounter alot of different colours and alot of the procedures aren't as simple as you'd expect! I could find some nice preparations out of inorganic syntheses to start you off if you'd like...

ScienceSquirrel - 17-5-2011 at 03:49

I have made these oxalate complexes;

http://icn2.umeche.maine.edu/genchemlabs/Oxalates/oxalate3.h...

The iron complex is particularly interesting as it is chiral and will undergo photoreduction as well.

http://en.wikipedia.org/wiki/Potassium_ferrioxalate

spong - 17-5-2011 at 04:25

What about ferrocene? That's a pretty cool one and you could make all sorts of cool ferrocene derivatives.

DJF90 - 17-5-2011 at 04:49

The issue with ferrocene is that cyclopentadiene (CpH) is not an easy reagent to come across and neither is its synthesis simple. Unless anyone has a nice method? Cp*H is probably easier to prepare, but the synthesis is fairly long winded for a relatively small mass of product obtained.

ScienceSquirrel - 17-5-2011 at 07:34

You could try making some Werner complexes, they were very important in understanding coordination chemistry and they have some nice colours.

http://wwwchem.uwimona.edu.jm:1104/lab_manuals/Werner2.html

Acetylacetone comes up on eBay from time to time and that makes some nice complexes.

spong - 18-5-2011 at 01:55

Quote: Originally posted by DJF90  
The issue with ferrocene is that cyclopentadiene (CpH) is not an easy reagent to come across and neither is its synthesis simple. Unless anyone has a nice method? Cp*H is probably easier to prepare, but the synthesis is fairly long winded for a relatively small mass of product obtained.

It's usually prepared from the retro diels alder of dicyclopentatiene as needed, I think it dimerizes if left for too long. He's working in a full lab so that shouldn't be too hard to find or order. I think the easiest way would be the reaction with KOH and FeCl2 or perhaps via the NaC5H5 if sodium metal is available.

ssdd - 18-5-2011 at 16:41

Hi all, sorry I haven't responded, things got busy all the sudden!

The Werner complexes sound like an easy/interesting synthesis, I may try one of these tomorrow if I find a hour or two to experiment (this is likely).

Also, I did look at ferrocene as a possible synthesis, but I am somewhat hesitant of the time needed to complete the synthesis (mainly due to the cracking of the dimer)...

I may also try the Lead Acetate, though I'm not sure if we have the Pb3O4 laying around, but you never know!
Quote: Originally posted by DJF90  
To be honest, the chromium acetate preparation isnt organometallic chemistry, due to the lack of a fundamental Metal-Carbon bond. However, it appears you enjoyed it all the same; as such, may I suggest you go deeper into the field of complex chemistry - you'll certainly encounter alot of different colours and alot of the procedures aren't as simple as you'd expect! I could find some nice preparations out of inorganic syntheses to start you off if you'd like...

This is very true, if you have some ideas they are more than welcome!

Thanks for the ideas!
ssdd - Tim

DJF90 - 18-5-2011 at 17:23

Quote: Originally posted by spong  
Quote: Originally posted by DJF90  
The issue with ferrocene is that cyclopentadiene (CpH) is not an easy reagent to come across and neither is its synthesis simple. Unless anyone has a nice method? Cp*H is probably easier to prepare, but the synthesis is fairly long winded for a relatively small mass of product obtained.

It's usually prepared from the retro diels alder of dicyclopentatiene as needed, I think it dimerizes if left for too long. He's working in a full lab so that shouldn't be too hard to find or order. I think the easiest way would be the reaction with KOH and FeCl2 or perhaps via the NaC5H5 if sodium metal is available.


Thanks for that spong, but I'm well aware that it comes as a dimer and requires cracking prior to use. The point of my post is that, for the amatuer who cannot just "order it in", there is a distinct lack of accessibility to this material.

@ssdd: I'll have a look sometime tomorrow and see if I can pick out some nice ones for you.

ssdd - 23-5-2011 at 17:09

Hi all, I am quite happy to report that last Thursday I successfully made the first 3 Werner complexes mentioned on the above website. This was a very colorful process to make each of these and I enjoyed it.


Each complex made, from left to right: cis-tetraamminecarbonatocobalt(III) ion, cis-tetraamminediaquacobalt(III) ion, and hexol

The Hexol has very pretty and interesting crystals which were, sadly, too small to photograph easily...

I may try the other series starting with CoCl2 this Wednesday

ssdd - Tim


[Edited on 24-5-2011 by ssdd]