Monday, April 29, 2013

Aldrich: Proactive for Pyrophorics

Anyone ordered a pyrophoric reagent (butyllithium, DIBAL-H, Grignards, etc) from Aldrich lately?
Notice anything different?

For those new to the blog, I work at a relatively small biotech company, and as such do all my own ordering, from catalog lookup through payment submission. Last week, we required 100 mL of a soluble alkyl-aluminum reducing agent, so I made my order and waited for delivery. Instead, I got an email from Aldrich's Product Screening Team:
Greetings:  An item you've ordered is extremely hazardous. Please provide, at a minimum, a paragraph of how you will handle this material...
Whoa! Don't get me wrong, I'm all for enhanced laboratory safety, but we've ordered kilos of sodium hydride, liters of n-BuLi, and never encountered this particular safeguard.

When the aforementioned reagent (finally) arrived, it had the following label prominently featured on top:
"WARNING! The bottle inside this can contains a PYROPHORIC CHEMICAL. Exposure of this chemical to air as a result of careless handling or breakage of the bottle could result in spontaneous combustion of the chemical and extreme danger. This chemical should be handled only by trained, experienced and qualified personnel. Failure to follow the proper handling techniques could result in serious injury. Do not handle, transport or store the enclosed glass bottle unprotected!
     We strongly recommend retaining the metal can as a protective container for storing and/or transporting the inside bottle. 
NOTE -- Any literature included in this package must be read before attempting to use this chemical.      ALD-0056"
Double whoa! Now, I've been doing this a while, and I honestly don't recall seeing such strongly-worded labels on the outside. The label appears to be affixed a little differently from the standard product label below it, leading me to believe it's a recent addition to these product lines.

Somehow, I suspect that the increased safety precautions may have something to do with the ongoing legal battle out at UCLA.

Readers: Anyone from Aldrich read this blog? Can anyone weigh in here?

Update, 4/29: Since Andre asked so nicely in the Comments, I've included a picture, below:

Goodness, gracious, great bottle of fire!

Saturday, April 27, 2013

#ChemMovieCarnival: Closing Credits

Missed 'em? See Day 1, Day 2, or Day 3!

[Cut! That's a Wrap]

The sun's setting on the final day of filming. Champagne flutes float around, and cast and crew celebrate another one "in the can." Who wants to help strike our #ChemMovieCarnival set?

24. Over at Chemtips, Brandon accidentally spills some "Hollywood Acid" on the floor, and watches as it eats all the way into the basement. Beware the Dip! Seriously, though, he give great advice on handling and care when using straight HF. Bonus points for using an Adult Swim cartoon clip to prove a scientific premise.
Movie: Who Framed Roger Rabbit?
TV Shows: Breaking Bad, Robot Chicken

25. In a valiant second effort, Vittorio tells us more about his favorite crime procedural, NCSI. They apparently have a super-cool mass spectrometer capable of labeling individual components - despite them occurring at the wrong masses. "Non-Chemist Ion Spectrometer," indeed!
TV Show: NCIS

26. Speaking of wonder instruments, Jim emailed me a fantastic guest post about James Bond doing drug discovery. In the rain forest. With a "portable GC." Cure for cancer sure to follow...
Movie: Medicine Man

27. ChemBark sends over a favorite clip of Martin Sheen acting presidential, and apparently pulling a one-liner out of his hat for...table salt (N-A-C-L, CJ). Kary Mullis, for the record, was probably LOTS of fun to sit next to, if Paul's memory serves.
TV Show: The West Wing

27a. ChemBark bonus - A show forever welcome on this blog, where an English a French starship captain confesses he flunked O-Chem.
TV Show: Star Trek:TNG

[Update, 4/28] 28. Jeez, Vinylogous! The door had nearly shut, and you had to go post this gem from a long-running NBC sitcom about a struggling paper company. Bonus: eyewash humor!
TV Show: The Office

Thanks to everyone who made this a great carnival! 
As they say, see you at the movies (hopefully with a better scientific advisor).


~Fin~

#ChemMovieCarnival Guest Post: Jim Explores the "Science" in Medicine Man

A few nights ago, a random Twitter encounter led to a fantastic email submission from Jim Leahy, who goes by @usffan. As Jim points out, the Sean Connery vehicle Medicine Man contains some laughable chemistry moments (note: I've lightly edited for style and linkage, but it's otherwise untouched):

***


When I saw See Arr Oh’s #ChemMovieCarnival, the first movie that popped into my head was Medicine Man, a 20-year old movie that I recall prompting many belly laughs.  To set the stage, this is how Netflix (which rates it as a 3.5/5 star movie!) describes it:

Reclusive scientist Robert Campbell (Sean Connery) discovers a flower extract in the Amazon rain forest that cures cancer. He tries to duplicate the life-saving formula, but clear-cutting developers and American bureaucrat Dr. Rae Crane (Lorraine Bracco) hinder Campbell’s efforts. When a native child falls ill, the scientist must decide whether to save one life with the last of the serum or keep it for further analysis.”

James Bond AND a flower extract that cures cancer? 
What could possibly go wrong? (well, other than not wearing protective eyewear?)

I was disappointed to find that Netflix doesn’t offer the movie online, and when somebody pointed out on Twitter that Derek Lowe’s very first post on In the Pipeline was about this movie, I thought about just skipping it. Fortunately, I found that the entire movie exists onYouTube, and decided that it really needed to be a part of any #ChemMovieCarnival.

For the sake of anybody who wants to watch the movie, I’m not going to spoil any significant plot points. This is just about the “science.”

The two scientists involved in the movie are a botanist (Robert Campbell) and a biochemist (Rae Crane) who has “degrees from CCNY, Berkeley and Cambridge and is the only person to win the Thurman Award twice.” Campbell has been working in the Amazon rain forest for years, being supported in his research by Aston Pharmaceuticals and has asked for a new research assistant as well as a gas chromatograph. Crane makes the significant journey into the rain forest (including a pretty extensive hike and a canoe ride) with the GC in tow to reach Campbell’s makeshift lab (presumably, vendors such as Agilent and Perkin-Elmer don’t ship to the rain forest!). When Crane arrives, it’s night time and Campbell is pretty hammered (no telling if the drinks were shaken, not stirred). So Crane sleeps for the night under a tree. This is where the scientific fun starts.

The next morning, when she wakes up, she discovers that Campbell is starting to unpack the instrument, which he miraculously has up and running within minutes. My first thought was “wait, what are they using for carrier gas?” although later in the movie there’s a shot of tanks and regulators (AirGas apparently does deliver to the rain forest). After some banter, Campbell asks Crane “what am analyzing?” which she answers with the question “did you run a baseline?” Not sure how that would help answer exactly what Crane is analyzing, but it’s good to know that the biochemist is keenly aware of standardizing the instrument. And what an instrument it is!

Campbell has injected a sample into the GC, a partial trace of which looks like this:


As Crane starts to examine the chromatogram, she discovers that nearly all of the compounds are “known” 

For those of you who understand gas chromatography, you know that a basic requirement is that compounds have to be sufficiently volatile that they can be converted into the gas phase before they can be analyzed for retention time along a column, which makes the instrument’s ability to vaporize silica, sodium phosphate, sodium nitrate and ferric chloride pretty remarkable, especially in light of the fact that it’s an older model GC. Frankly, I’m much more impressed with the compound coming off as peak 39. Remember, these are all the unremarkable “known” compounds, according to Crane. I’m pretty sure finding NaCl2 at all, let alone in nature, would be worthy of publication in Science or Nature. Which is when you start thinking “wait, how are they identifying these compounds?” Remember, this is just a GC – what kind of detector are they using that identifies all of these inorganic compounds? We’ll come back to that…

Campbell seizes on the words “nearly all,” which leads them to focus on peak 37, which isn’t apparently “known." 

Clicking on the peak reveals the structure of peak 37 to be:


Sorry, I couldn’t get it to come into focus any better than that, but it’s the best view of the entire molecule in the movie. They do have a partial shot that allows a little better view of some of the details:

Where to start! Apparently this GC has the ability to determine structures of unknown natural products, which would really come in handy, although to be fair, it doesn’t seem to be able to distinguish stereochemistry, and I count at least 8 stereocenters in this partial shot of peak 37. Then again, those stereocenters are insignificant compared to the two Texas carbons in the bottom ring. Crane marvels that “it’s an acid derivative,” which I can only assume refers to the side chain that’s partially cut off in the close up but appears to suggest that the alcohol (which may be stereocenter #9, by the way) exists as a bicarbonate. Campbell’s only concern is whether it can be synthesized, to which biochemist Crane replies “uh-uh, it’s Mother Nature’s kitchen sink.” Apparently the biochemistry program at Cambridge includes an extensive synthetic organic chemistry component.

It turns out that peak 37 appears to be the “cure for cancer.” I would sure love to know the pharmacokinetics of this compound which may be competitive with the least Lipinski-like small molecule to be considered for clinical trials. Lots more scientific comedy ensues, such as the ability of a botanist and a biochemist to apparently diagnose lymphatic cancer, but a few highlights include their formulations expertise at finding a suitable injectable of the extract and the stunning response time that comes from a single dose of 37. I also suspect that the FDA would not take kindly to the human testing of most assuredly non-GMP material.

None of this should keep you from watching the movie (although the 24% on Rotten Tomatoes might), and I suspect that there’s lots more scientific comedy to be mined here. Either way, it deserves a special spot in the #ChemMovieCarnival.

(Thanks, Jim! Great post. -SAO)

Friday, April 26, 2013

Podcast: Deborah Blum talks to CJ and SAO, Part II

A few weeks back, Chemjobber and I spoke with esteemed science writer Deborah Blum, of Wired and Poisoner's Handbook fame, among many other things.

Half of the chat appears over at CJ's place, go have a listen!



Timepoints:

0:01 - Introduction
0:35 - Science Writing "Death Grip"
2:07 - Navigating life through science
4:45 - "Chemical-free" (oh, boy...)
8:58 - The Great Golden Day of the Newspaper
12:42 - Crowdfunding newspapers?
14:35 - Advice for new science writers: "It's a lot of fun!"
15:34 - The thousand mealworm cookies
17:38 - Now appearing at your local Kroger - insects!

Thanks again to Deb for a fantastic conversation.

Thursday, April 25, 2013

Throwing Down for #RealTimeChem Week

Carmen and Stu have been free-hand drawing some fancy stuff on Twitter to celebrate #RealTimeChem week. I thought I'd add in my two cents:

Behold, maitotoxin!
P.S. I totally cheated, and glanced at a paper to do this. There's no WAY I'm memorizing that!

Monday, April 22, 2013

#ChemMovieCarnival: Act Three

Click here for Part 1 and Part 2

The directors are directing, the editors editing, the key grips gripping, supporting actors supporting, and the best boy...well, whatever he does, he's doing!

17. John of It's the Rheo Thing recaps the extra-fun chemical err....duplicity, in a movie by the same name. Honestly, this might be the first silicone-meets-Hollywood post that doesn't revolve around typical body modifications (it's a hair gel, folks). Bonus points for an accurate assessment of acting talents.
Film: Duplicity

18. For a post where she's (allegedly) avoiding discussing chemistry (or physics!), Renee really captures the teen angst vs. science teacher influence angle. Not to dis Jena Malone, but antiseptics are more than just fancy soap.
Film: Donnie Darko

19. Chemically Cultured primes our minds to the existence of hardtofindium, dalekanium, dilithium, and the new vogue fake element, unobtainum. Tom, I'd really like a copy of that poster!
Films: Avatar, Star Trek, Star Wars, The Core

20. Smells like three things in this post: burning thermite, methylamine, and the start of #RealTimeChem week! At Chemistry Blog, Mark lets the sparks fly, but doesn't seem to have perfected Walter White's lock-picking technique yet.
TV Show: Breaking Bad

21. New blog alert! Tien, of Must Love Science, covers the *cough* physics *cough* of a well-loved SciFi epic. Simulated gravity? There must be an extra-large chunk of dark matter outside each ship, no?
TV Show: Battlestar Galactica

22. Next, another Chemistry Blog stalwart discusses chemistry moments cropping up in his favorite crime drama. Azmanam's doppelganger (Dr. Spencer Reid) encounters some interesting cases, like that one where the bad guy dunks his victims in methanol to preserve their scent. (Bleargh!).
Also, plywood!
TV Show: Criminal Minds

23. Curt wrote this excellent entry, and he writes a pretty good blog, too: Minglingken, Mixing Knowledge. In this post, we have Russell Crowe, a good-guy whistleblowing biochemist, up against the wall of Big Tobacco. I never knew coumarin was used in cigarettes...
Movie: The Insider

Honorable Mentions: Vittorio and Gavin Armstrong sent along these "science-y" pictures from various forensic TV shows:

Assuredly not poly(vinyl acetate)
Show: Dexter
Hey, look, it's nitrogen! At least it's not chicken soup this time...
Show: NCIS
Want to play along? There's still time! Email me at seearroh_AT_gmail, or tweet (@seearroh)

Update 4/22/13 - Added minglingken entry; assigned authorship to Curt (thanks!)

Saturday, April 20, 2013

#ChemMovieCarnival: Take Two!

(Missed the first act? Click here!)

We're on location, tracking down the best (and worst) in cinematic chemistry.
What have our chemists-cum-scriptwriters come up with today?

10. First, Vinylogous over at Not The Lab visits 1971, learning all he can from a snooty science teacher more interested in nitric acid 'wart remover' than proper pedagogy. H-O-H, indeed!
Film: Willy Wonka and the Chocolate Factory

11. Vulcans bleed green; the Predator's blood glows in the dark. If you've ever wondered why all these aliens circulate such odd visceral hues, ScienceGeist has the explanation. Trimeric copper complexes? Yes, please!
Films: Star Trek, Predator, Avatar, Alien

12. Andre the Chemist storms back into the ring for another round. This time, he considers chemical "Rosetta Stones" - does our scientific notation only make sense to us? And where does the Enterprise store all those extra atoms for the replicator?
TV Show: Star Trek: TNG, Futurama
Film: Contact

13. Superma, err, Stu Cantrill, flies around Earth beyond the speed of light, all the way back to 1983. There, he meets Richard Pryor, who computes the precise elemental make-up of Kryptonite. Who knew there'd be that much dialium? DANGER!
Film: Superman III

14. At Kentucky Chemistry, N. Tesla opines on the oft-utilized plot device of lit cigarettes creating fireballs from gasoline vapors. Please don't try this at home; peer-reviewed pyrolysis research (!) suggests it's pretty tough, and Tesla's home experiments (!!!) seem to corroborate.
Film: Zoolander

15. Next, Trends In Science's Marcel Swart reviews the emotional chemistry found in a personal cinematic favorite. Lead character Tita cooks with some decidedly 'non-traditional' ingredients: catalyic tears, sensual rose petals, and fiery match-heads.
Film: Como Agua Para Chocolate

16. Over at Wired, plucky Deborah Blum picks apart the highly suspect "HCN disfigurement" scene from the recent James Bond flick, much to her son's chagrin. Who knew spies used to carry around poisonous eyeglasses?
Film: Skyfall

It's still not too late...submit those Chem Movie Carnival entries before Monday! Send to seearroh_AT_gmail, or @seearroh on Twitter. Hashtag: #ChemMovieCarnival. See you at the movies!

Thursday, April 18, 2013

#ChemMovieCarnival: Aaaand ACTION!

See also Day 2 and Day 3!

[Quiet on the set!]

We've set the stage, fixed the makeup, and turned on the cameras.

[Places, everyone!]

Who's up for Scene 1 of the Chem Movie Carnival?

1. First, viajamos a España, where contibutor Isi seeks some...relief, using Biuret adducts to detect would-be pool pissuers, err, "yellow-handed."
Film: Torrente 2: Misión en Marbella

2. Next, we'll stay in Europe and visit blog stalwart V. Saggiomo, who's donned some shades and a mullet to talk about everyone's favorite uber-resourceful agent MacGyver. Serious question at the end: what would MacGyver actually do with Parafilm? (besides fix everything)
TV Show: MacGyver

3. Jumping across the pond, we visit Chemjobber, on his [secret location deleted] rural soundstage in Somewhere, USA. Based on his post, I'm pretty sure he's either a) currently tunneling out of a bunker, or b) considering opening up a nanobrewery. Either way, there need to be more distillations run on movie sets!
Film: The Great Escape

4. If you dare, step into the ring with Andre the Chemist. He's got a bone to pick with a certain science-y, "not good, but not bad" comedy starring David Duchovny (note to self: must watch this movie). Andre picks up on several cover-your-eyes leaps of scientific faith, including nitrogenous life and the wrong anti-dandruff shampoo.
Film: Evolution

5. Glen Ernst reviewed Flubber, err, another famous Disney movie where a floating, bouncy polymer took center stage. Glen decries improper PPE, plays up Dr. Boom, and has an open contest to sniff out potential Texas carbons on a set design...
Film: The Absent-Minded Professor

6. Beth Halford, C&EN reporter extraordinaire, would like you to know that the only rule about Chem Movie Carnival is that you don't talk about Chem Movie Carnival. 
Also, I really hope I never spill lye on my hands, or meet Tyler Durden.
Film: Fight Club

7. Do you have a mechanical heart slowly killing you from the inside? Well, if so, Collapsed Wavefunction has just the thing! Pavilion blueprints, meta-palladium, and a do-it-yourself particle accelerator! (Snarky butler not included)
Film: Iron Man 2

8. YO, JOE! (Well, OK....Co-braaaa!) Over at Behind NMR Lines, Andrew muses on sinking ice, city-eating nanobots, and the ever-expensive line items on Cobra Commander's Excel spreadsheet. Maybe he could just hire himself some better scriptwriters... (Hsss! Destro! Hsss!)
Film: G.I. Joe: The Rise of Cobra

9. Gee, I forgot that Batman / Iceman / the Saint used to build giant lasers at a school for geniuses. Lucky for me, Sarah Cady to the rescue! Love to get some P-Chem up in this Carnival, although someone's gonna have to explain to me what an "argon matrix" really is. 
Laser popcorn, anyone?
Film: Real Genius

More to come tomorrow...Stay tuned!

Chemical Nostalgia: Being the Mark

If you haven't read it yet, Paul's written a really great reminiscence about his first chemistry conference over at ChemBark. It's funny how reading someone else's account causes you to immediately flash back to your own "first time," especially since mine didn't go quite so smoothly...

I'll never forget my first pharma internship during the summer of my sophomore year. It was my dream job: smart people in pressed slacks, automated fraction collectors, a communal coffee pot, and (gasp) top-shelf Pentium II computers at work stations, equipped with (dial-up) SciFinder!

My boss wanted a coworker and I to present a poster at the big ACS meeting that summer. We would be one of about 400 posters on the floor, but I didn't care, I was going to go talk science with scientists. We stayed up late the night before, changing the poster layout* and gluing the backings down for each image; this was before cost-effective full-poster printing. I bought a new shirt and tie, and got a haircut. When the session came, I arrived an hour early to tack up my opus, and eagerly awaited the flood of potential listeners.

If you're familiar with poker, you know the expression "If you don't know who the mark is, you're the mark." That means someone's always at a disadvantage, and will likely lose all their money in fast order. Worse yet, the senior players know you're the mark, and take you down accordingly. With hindsight, it's clear to me: someone needed to present, but none of the staff scientists wanted to go, so they sent me.

I was the mark. And I got eaten alive.

"What's the platform?" "Umm..." "Any targeting groups?" "Maybe." "Tell me more about [pathway X]" "I think it has to do with cancer...?" "What's the SAR around that site?" "Lots of compounds."

My colleague was nowhere to be seen. I was on my own for most of those hours.

I'll never forget my intense embarrassment and nervous, hesitant answers. When the session ended, I just grabbed the poster and ran out of the room. Didn't go to any talks, didn't go back the next day. I'm sure my poster still sits at the company, buried under a pile of old journals.

*Fast forward a few years: my second poster had everything: color-printed on one rolled-out sheet, copies of abstracts and company contacts to give out to listeners, coached one-liners for questions, the works. That one went worlds better.

Wednesday, April 17, 2013

Precious Serendipity

Serendipity often drives scientific inquiry.

Ask a famous scientist - Feynman, Archimedes, Fleming, to name a few beneficiaries - they'd tell you it's better to be lucky than good. But Pasteur's paraphrased "Fortune favors the prepared mind" spells things out more clearly; diving into the nitty-gritty of chemical transformations often brings up a chance pearl of wisdom.

Such is the case for a recent JACS ASAP, out of the Wang group at Xiamen University in China. Let's set the stage: the scientists attempt to create a stabilized bimetallic cluster compound from gold, silver, and hemilabile P-N ligands. When the starting Ag-Au complex meets acetonitrile and methanol, something interesting occurs: a dimeric crystalline compound forms, bridged by two fully deprotonated acetonitriles!
Those golden pyramids are pretty schnazzy.
Source: JACS | Wang group
So, why am I so excited?

1. That's a CCN (3-) anion stuck in there! What if you could, say, build a tetra-substituted carbon center just by adding electrophiles in sequence?

2. C-H activation of sp3 bonds = hard. Especially at room temp.
Well, there's (technically) 6 sp3 C-H bonds missing in that complex!

3. The authors note that water forms as the reaction progresses. Most nitriles, in the presence of Au/Ag catalysts and water, will hydrate to form amides. Not so here.

4. The authors point out that a gold oxo intermediate must be present for the cluster to form. They also point out that similar gold oxo catalysts (and silver oxide bases) pop up in the literature. Perhaps crazy intermediates like this commonly arise in gold-catalyzed reactions?

The best part? Studies like this always leave you with more questions than answers.
Perfect fodder for future projects.

Thursday, April 11, 2013

Friday Fun: Mo' Moonshine, Mo' Polymer

Blog Bait (n) - A pithy graphic just begging to be discussed on the chemblogsphere...

Straight from the pages of ACIEE comes the latest from the Nuckolls group: ROAMP, or metathesis polymerization of strained cyclic alkynes (Schweeet!)

NMR kinetic studies indicate that the active molybdenum catalyst, initially trapped in a dimer, can be broken apart just enough by methanol to make polyalkynes. This procedure even works in the presence of air, water, or phenolic additives - usually catalytic death knells.

Kudos to Nuckolls' group, but their coup de grace may in fact be the accompanying cover graphic, below. Your eyes do not deceive you: they compare their sexy new reaction to a steaming copper moonshine still, hidden deep in the woods.

Credit: D.W. Paley, Columbia | Angew. Chem. Int. Ed.
Mo' Molybdenum, Mo' Polymers.

Happy Friday,
See Arr Oh

Sunday, April 7, 2013

WWWTP? Operatic Chemistry in the Boston Globe

Has anyone seen the fantastic writeup by Carolyn Johnson in the Boston Globe today?

Johnson covers the J. Chem. Ed. recently penned by Prof. João Paulo André, of the Universidade de Minho to celebrate the storied use of poisons in opera. I hadn't realized, honestly, that this rich history involved poisons from such a wide variety of plants, minerals, and animals, or that specific references to each substance can be found in the libretti. Fascinating!

Unfortunately, the graphic that accompanies the story takes a few chemical liberties, which I've circled:



(Update 4/7/13 - I should point out that more structures are right than wrong here, which a commenter points out is more than you usually see in mainstream media. Kudos to the BG for covering the article the way they have)

I've written a short note to the author, reprinted below, and I will post any response I receive.
Dear Carolyn:

Good afternoon! My name is See Arr Oh (a pseudonym), and I blog at Just Like Cooking, a chemistry blog aimed at general-interest audiences.


I noticed your article in today's Globe, and I want to applaud you for your outreach. The article is well-written, and the science seems solid.


However, the image that accompanies your article includes several inaccurate structures for the discussed poisons. For example, the structures of mannitol don't show explicit stereochemistry (3D structure); these might well be glucose drawn this way. 

Scheele's Green is actually a copper complex; trimethylarsine is the poisonous gas that evolves from the dye. Arsenic trioxide and mercuric sulfide aren't actually monomeric, as drawn, but adopt several different crystal forms involving multiple As and Hg atoms, respectively.

Finally, the neurotoxin shown in the "snake venom" box is not actually venom, rather, it's anatoxin-a, from blue-green algae. 

Please consider changes to the illustration. If you need anything further, don't hesitate to contact me at seearroh_AT_gmail.com

Sincerely,
See Arr Oh

Twisted Olefins in "Click" Chem?

Everyone digs the copper-catalyzed "click" reaction between azides and alkynes - its fruits have ripened into applications for protein labeling, drug analogs, and green synthetic approaches.

Science Express just released an intriguing read from the Fokin group, which uses reaction calorimetry (how hot? how fast?) and mass spec isotopic enrichment studies (where'd that atom come from?) to study the copper-catalyzed click. Using calorimetry, Fokin's group determines that two copper atoms must cooperate to form the desired triazole; the uncatalyzed reaction limps along (~7%) in the same amount of time that the catalyzed reaction - which gives off a brief burst of heat - reaches completion (>96%). 

To try and tease out which copper does what, the team synthesized an isotopically-enriched 63Cu catalyst, which they added to a "normal" (63Cu / 65Cu) isotope blend of a copper-bound acetylide. Time-of-flight mass spec showed isotopic enrichment of copper in the resulting isolated copper species. How the heck can that happen?!? 

Well, it can't. . . unless, of course, there's an intermediate where the two copper atoms interchange. Enter the crazy, wild world of gem-dimetalation, a concept several groups (Fürstner, Blum,  Gagnéhave recently studied for a variety of d10 metals (Pd, Ag, Au). Even more crazy, the enrichment indicates that an NHC ligand "jumps" between the two copper atoms, hardly usual behavior for such a strong donor ligand. To explain these results, Fokin constructs a modified catalytic cycle, shown below:
Source: Science | Fokin group, Scripps
Check out that prism-shaped intermediate in the lower left. Anything seem strange about it?

Think, for a moment, about axial chirality. What comes to mind? BINAP, certainly, or the M and P descriptors for allene (cumulated double bonds) chemistry. Well, unless I'm missing something, this intermediate may be the first representation of olefinic axial chirality I've seen. To invoke this intermediate, the alkene in question must really be something special, since the azide has to be disposed roughly 90 degrees out-of-plane! 

Usually, alkenes like to sit in sp2 -hybridized space - flat, like a sheet of paper. Rotational energy barriers exist to interchange E to Z olefins, but they usually need lots of energy (heat, light) or a charged intermediate. Here, we have an almost-room-temp, neutral, 3D alkene intermediate: a rare duck indeed.