This is what tetrakis should look like
For ψ*ψ, who wants to know what pretty Pd(PPh3)4 looks like. This is the stuff from Strem that we keep in our glovebox. It's pretty air- and light-sensitive, so best to keep it under nitrogen.
Also, is it me, or is tetrakis from Aldrich of a much poorer quality than the stuff from Strem? I try not to buy palladium complexes from Aldrich anymore after I was warned by some profs, as well as some interesting experiences with the tetrakis they have...
10 comments:
Thankya. It looks like I need to make a fresh batch...aaaand maybe redo a reaction.
Posted on the wrong blog entry:
Once upon a time I made 10 g of fresh tetrakis and bottled 0.5 g in each of 20 bottles under nitrogen. I went on a sabbatical and put them in a freezer. When I got back I had 20 bottles of 20 different colors from green through yellow to brown.
I was trying to do some Suzukis when I first got on this new project, and one of the guys who had tried (and failed) these same reactions handed me a bottle of tetrakis from Aldrich. I grimaced because my old supervisor had warned me against S-A's tetrakis. I think the words he used were "rancid garbage".
I opened the bottle from Aldrich and weighed out 24 mg of brick dust. Actually, brick dust might have actually done a better job. So, I tossed the bottle out and immediately ordered one from strem that now sits on the bottom shelf of the freezer wrapped in parafilm only because I couldn't find any teflon tape.
I don't do much with metals now days, but according to the legend, Sigma-Aldrich organometallics = bad and Strem = excellent. Is that true?
I don't know about blanket statements like THAT. I've had no problems with the Pd(II) compounds I've gotten from Aldrich. I tend to trust Strem more with air-sensitive organometallics, however.
I think it's a little of both. On the whole, reagents that I've ordered from Strem have been excellent. But palladium (II) reagents that I've used from Aldrich have gotten the job done. I've never sat down and run one against the other head to head (aside from the tetrakis).
I do, however, order all of my ligands that aren't triphenyl phosphine from Strem.
I do not trust any tetrakis I don't make myself, period. I've been burned by both Aldrich and Strem with many of their palladium catalysts. Plus, tetrakis is a super simple prep.
Mitch
The only palladium compounds I would consider buying from Aldrich are palladium chloride, palladium acetate and palladium dba.
It is a good job there is a high throughput of new inexperienced students willing to buy their stuff before anyone realises what they've do, otherwise they'd never sell anything.
If your tetrakis has gone 20 different colours, washing it again with ether (or was it ethanol?) under nitrogen gets it good as new.
what the hell is tetrakis...well it's new to me...i don't know anything about it....
but every comment here seems to know what it is...that's good...
anyway...it's a new info and input to me...thanks
Aha! An engineer delurks!
zaki: tetrakis is chemist-slang for Pd(PPh3)4, a magickal palladium catalyst.
Not being able to use subscripts in comments is really annoying.
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