1. RB Woodweird on October 23, 2009 10:35 AM writes...

So it was that two such graduate students, both new to the game, stood together in the third-floor laboratory of Professor William Stringfellow, nervously eyeing an innocuous silvery canister. Neil Coit, a pudgy, shaggy-haired young man, was sweating much more than the temperature of the room demanded. He looked beseechingly at Jen Perrelli. She shrugged her shoulders. They had entered grad school together, last fall, and had independently cast their lot with Stringfellow. They had been assigned hoods in this lab, one of three small contiguous rooms in which the group worked, and they had each begun a small project related to Stringfellow’s palladium research, in which divalent palladium complexes were used to prepare otherwise inaccessible crowded carbons by insertion of metal-bound ligands into unactivated carbon-hydrogen bonds.
They were hoping to use their preliminary results and their growing command of the chemistry to work on total syntheses of some of the natural products that their mentor had targeted, beautiful structures with exotic names like teleocidin B-4, neomangicol A and B, and combretastatin A-4. Instead, their boss had come into the lab bearing the silver can now resting on Neil’s benchtop and informed them that they were the vanguard of a glorious new chapter in the group’s storied history, for they were the shocktroops, the pioneers of the shining future of the preparation and synthetic uses of molybdenum ligand Mo(�2-C70)(CO)3(dppe) and its fellows. He had then plopped the canister down and departed, leaving the two to reset their calendars.
They had gone to the library and dutifully investigated the synthesis of molybdenum ligands. What they had found was that they all sprang from the common precursor molybdenum hexacarbonyl, and molybdenum hexacarbonyl was profoundly toxic. Now, this should not have concerned either of them, for they had some experience with the safe manipulations of toxic chemicals. And they had hoods and gloves and goggles and aprons whenever they felt the need to don the same. Both had worked with cyanide and phosphine and hydrogen sulfide, all in their own right probably more deadly than molybdenum hexacarbonyl or any or its liganded relatives. Plus, many of the reactions which led from the hexacarbonyl to the various derivatives had to be done under argon, in air-tight glassware which itself furnished a primary safety barrier.
What had spooked them was an article in an old Chemical and Engineering News that Jen had found while cleaning up a huge rotting pile of old magazines in the grad students lounge. When she read it, she got chills. When she gave it to Neil to read, he was pale for an hour.
Sometime in August 1996, Karen Wetterhahn, a professor of chemistry at Dartmouth, was preparing a standard sample for an NMR. The standard was dimethylmercury. Already an international authority on the carcinogenicity of chromium, Professor Wetterhahn was undertaking the study of how organomercury compounds do their damage to cells and tissues. One warm New Hampshire day she put on latex gloves as usual – as everyone who worked with such compounds did – and in the protection of the hood prepared to transfer a minute amount of the liquid dimethylmercury into an NMR tube with a pipet. Jen and Neil had done this same operation a thousand times, minus the mercury. The NMR tube is as thin as a drinking straw. The pipet is fitted with a rubber bulb, and the airspace above the liquid is so large that liquids that are dense or have a low surface tension tend to run out the narrow tip of the pipet with little provocation. There should be a better way to do it, but the operator becomes comfortable with his tools, even flawed tools. Often drops of the liquid rush out, missing the NMR tube altogether. Unfortunately, the dimethylmercury was both dense and of low enough surface tension that a drop or two missed the tube and landed on Professor Wetterhahn’s gloved hand. She saw this, but was not overly concerned. Latex gloves were the accepted protection. She removed the gloves and disposed of them properly. If she was like Jen or Neil, she probably went promptly to the sink and washed her hands with plenty of soap just to be safe.
Five months later, she began to slur her words. She stumbled on level ground and was having attacks of severe abdominal pain. It was her field of expertise, so she may have suspected the truth. Hospital tests showed that she had 80 times the lethal dose of mercury in her body. The drop of organomercury had penetrated her gloves and skin like a shot. Latex had been no protection – it was a scientific urban legend that it was a barrier at all. Just 22 days after the first symptoms, her eyes gave out, her ears quit working, and she could not make a sound. She died four months later without waking from her coma. She left a husband and two small children. Karen Wetterhahn was only 48.
The moral of the story was too clear. Something you had dealt with safely for years could rise up and bite your ass off. Now the two had the silver canister in the lab, shining its evil and distorted vertical fisheye reflections of them like they were already trapped within its demonic grasp. It was a monolith, silent, dominant. Was this the one? Would they read the MSDS and follow all the rules, pull on nitrile gloves, slip goggles over their eyes, snap open the glass ampoule inside of a glovebag inside of a hood, never touching the stuff without layers of glass and plastic between them, only to find out in a month, a year, a decade that – oops, sorry: we were wrong. Our bad. Turns out that molybdenum hexacarbonyl seeps through those old things you were using. You should have been wearing Teflon gloves covered with stainless steel mittens. Hey, who knew? Too bad about the aggressively inoperable tumors, the paralysis, the dementia, the blindness. Told you to go to law school.
But the culture of chemistry, in which Jen and Neil were being steeped, did not permit hesitation. Reasonable precaution, sure, but timidity was for the other eighty-five out of a hundred. Open the bottle! Run the reaction! Just do it! was the message, no matter how many safety seminars the University made them sit through. Results were the object, and results came from experimentation, and experimentation implied the running of reasonable risks. So Neil knew he would get out his can opener and cut open the cylinder, because he did not want to be seen by his peers – and especially Stringfellow – as less than gung-ho in all respects. And Jen would snap the vial, inside a glove bag inside a hood, because she would feel the need to prove to the male-dominated faculty and the male-dominated graduate students that lack of balls did not mean she lacked balls.

2. Atom Recession on October 23, 2009 10:37 AM writes...

One great use of dimethyl zinc: Take it into the glovebox and unseal the container. Judge the dryness of your box by the volume of smoke evolved from the bottle. Even the most rigorously dessicated boxes will produce some smoke!

3. Canuck Chemist on October 23, 2009 10:41 AM writes...

I wish I could have witnessed it, but one of my old grad. school colleagues told me a tale of a plugged glass syringe containing dimethylzinc (can't remember if it was neat or not). The solution to the problem, which actually would seem to be generally useful for cowboy chemistry, involved tying a hammer to some rope, fishing it over the monkey bars and under the fume hood sash, and dropping the hammer on the syringe with a tug of the rope. Cool to watch the fireball while safely behind the plexiglass...

4. JAB on October 23, 2009 10:46 AM writes...

I always wondered what happened to that Library of Congress project. They were supposed to put it here at Ft. Detrick.......

5. Milo on October 23, 2009 11:17 AM writes...

I used to work for a company that produced trimethylaluminum. The safety demonstration always included someone squiting a 1/2 ml sample of the stuff (neat no less!) in to a steel pail. Fun stuff indeed.

6. Luke Weston on October 23, 2009 11:40 AM writes...

A video of interest:

http://www.youtube.com/watch?v=DyH09EvYRJk

Yes, it's diethyl zinc, and not dimethyl, unfortunately.

7. Philip on October 23, 2009 11:49 AM writes...

I suspect that RB Woodweird owes an atribution unless he is, in fact, the real S. A. Scoggin.

I will admit that I was quite spooked by the death of Professor Wetterhahn. Things that go boom with a ball of flame are sissy stuff compared to things that destroy your brain months later.

8. Rhenium on October 23, 2009 11:51 AM writes...

Excellent and entertaining post. :)

9. Anonymous on October 23, 2009 12:03 PM writes...

I once witnessed the evacuation of an entire chemistry building for several hours because a bottle (Not-So-Sure Seal) of neat diethyl zinc developed a crack in the glass while a grad student was cannulating it into an airfree flask. The fire department and the hazmat folks wanted nothing to do with that. The situation was finally resolved when someone manned up and went inside to finish the cannulation. I won't mention any names or places--to protect the innocent and the guilty.

Scary stuff. And a strong second to Derek's point. Use the toluene solution -- much safer.

10. Greg Hlatky on October 23, 2009 12:06 PM writes...

Polyolefin catalysts use triethylaluminum as activators. A plant engineer told me that they used neat TEA in the commercial process instead of a (non-pyrophoric) solution; much easier to handle, he said but did not elaborate. Presumably he wasn't changing cylindars or purging lines.

11. Anonymous on October 23, 2009 12:15 PM writes...

What is the passage from the first post from?

12. Arjun on October 23, 2009 12:17 PM writes...

As Atom alludes to, cracking open a vial of diethyl zinc and looking for smoke is somewhat of a standard procedure for assessing the quality of your glovebox atmosphere. Diluting the reagent into a more volatile solvent actually increases the sensitivity of the test.

And yes, it *is* possible to get your box into a condition where diethyl zinc will not smoke.

13. Nick K on October 23, 2009 12:34 PM writes...

Back in the 1850's Edward Frankland made dimethyl and diethylzinc, and thus made some important deductions about valency. How the hell he did it without incinerating himself I don't know. Trialkylboranes are equally pyrophoric, burning with a brilliant green flame. A possibly apocryphal story I heard at Imperial College was that the only way of disposing safely of these materials was to throw them off the roof of the Chemistry Building. Apparently the resulting sheets of green fire were extremely spectacular.

14. milkshake on October 23, 2009 1:31 PM writes...

Me3Al in toluene 1M soln is pretty tame stuff. (It is a great reagent for direct aminolysis of simple esters with amines). Pyrophoric stuff that always self-ignites at the tip of needle bothers me lot less than stuff that is supposed to be well-behaved, such as LAH or NaH except that sometimes it does not - when one gets a wrong batch that bursts in flames as soon as you open the can. Putting out 100g can flaming on the bench right next to your balances is no picnic.

15. processchemist on October 23, 2009 1:41 PM writes...

@ milkshake

I completely agree, having experienced the self ignition of a 100 g closed bag of NaH 99% in my hands (probably caused by a minor damage to the bag).
Two major lab accidents I witnessed were caused by small quantities of ether.

16. RB Woodweird on October 23, 2009 1:47 PM writes...

Philip: An oversight. I have blanket permission to extract S.A.'s material, but here is the attribution in the form of a link:

http://www.scribd.com/doc/19956600/A-Novel-and-Efficient-Synthesis-of-Cadaverine

Coming soon to Amazon for your prebound pleasure.

17. CMCguy on October 23, 2009 2:37 PM writes...

So after DEZ adventure at LOC did they come up with something else to accomplish this task of deacidification? Or as JAB implies did they make it someone else's problem? (BTW wasn't Ft Detrick a former ChemWarfare testing site?)

As milkshake effectively notes it is frequently stuff one knows or think has control over than lead to biggest problems.

18. Hap on October 23, 2009 2:46 PM writes...

Ft. Detrick used to be an US offensive biowarfare site, and now it's a biodefense site. I think it still has active BL-4 labs, for example. I don't know if it was a chem warfare site as well.

19. Sili on October 23, 2009 8:38 PM writes...

Oh. Dimethylzink. I had the cannister of the diethyl standing the hood next to mine for months until the org student took it back (not even sure what we had it down for).

Scary stuff about the Mercury. Of course the antivax nuts don't care that in that case it is methyl and not ethyl - they'll whine and shout about that and "antifreeze", "formaldehyde" and "ground up babies" no matter what. Personally, I'd hope that I was in a state to kill myself if I was in that situation. Luckily I don't have dependants.

I hope nothing of interest was lost in those LOC experiments.

:sighs: I wish I hadn't turned out to be such a bad chemist.

20. Anonymous on October 26, 2009 4:32 AM writes...

Sili, ethylmercury is less toxic than methylmercury, and its elimination is complete; it doesn't accumulate. That's why thiomersal is an ethylmercury compound.

21. chemist on October 27, 2009 9:24 AM writes...

Among other hot stuff, I've used neat DIBAL. It came in a metal cylinder from Alfa or Morton Thiokol, I think. You could watch the viscous, clear liquid ooze down the tygon transfer tube to the SS needle adapter / needle. I never had any bad incidents. Despite being pyrophoric, I also don't recall any flames shooting out of the syringe needle during cleanup. Just smoke and very slow ignition (which was deliberately, carefully allowed to make sure that most of the excess was consumed before proper quenching ... and because it was neat to watch).

22. Anonymous on October 27, 2009 10:23 AM writes...

@ 2, 12 re: box testing.

Often both TMA and DMZ are reacting with trace ether or other lewis basic ligands in your box atmosphere. If you use THF or DME with the catalyst open then you'll "always" have some floating around, thus always some smoke from your TMA or whatever. I've been told (possibly apocryphal) that TEA and DEZ don't have as many problems with "false positives" due to solvent.

It is possible to have a DRY box. Just inconvenient. My group uses a TON of TMA and even though you get a little smoke it's not bad to handle in the box. It's also so volatile and reactive that you can just let the box purge for a while and the material finds a nice place to make alumina (e.g. the transfer pipette residue). No fires when you remove stuff from the antechamber. That's much nicer than some other organometallics. . . .

23. Syn-Thesis on October 28, 2009 11:06 AM writes...

@ chemist: I've used neat DIBALH too, it's rather tame but takes a lot of patience to handle, it's so viscous. I used to clean the needles straight after using them with some acetone, but once I forgot and used water - BANG - sounded like a gunshot and made the needle fly through half the lab...

Dimethylmercury: We were once forced to take stock of all our chemicals due to a new online inventory system, when two friends of mine decided it was time to properly clean out the fridges. They found, in the very back of an old fridge, a small bottle of 100 ml dimethylmercury.
It was then when they decided that this fridge had to be someone else's problem...

24. Hap on October 28, 2009 12:04 PM writes...

As long as nothing happens to the fridge - then it becomes everyone's problem, whether they wanted it or not. Hope your (ex-)group has good life insurance.

25. Sili on October 28, 2009 12:59 PM writes...

Anonymous,

Sorry, I got my rant on.

I know that ethylmercury is harmless (relatively). But the anti-vaxxers insist on confusing it with methylHg in one of those cases where I'm really not sure Hanlon's razor applies. I don't know who to credit but when it comes to that subject I think this corollary fits better: "Any sufficiently advanced stupidity is indistinguishable from malice".

26. Hap on October 28, 2009 1:36 PM writes...

I don't think the stupidity is really very advanced at all. It's still really stupid - it's just persistent (because the people believe that falsehoods will be treated as truths if one only repeats them often enough. Since it works for presidents, I guess they figure it'll work for them, too.)

I guess I would prefer "Sufficiently repeated stupidity is indistinguishable from malice". The lack of a disproof or unrefuted logical flaw would probably constitute suffiency.