orange!! (the most exciting thing i've seen in a while)

You've seen a lot of the perylene diimides I've made. (In case you missed them, here they are.) To this point, they've all looked the same--red to violet in the solid state. This one is different. It's so tangerine it hurts a little. Also, it isn't a fibrous pancake--all the others give me long, flexible needles, if they crystallize at all (perylenes are infamous for gellating). This one actually behaves like a normal crystalline solid! And it's sparkly! See?



Why orange, though? This is neatly explained by quantum interference effects in a super-cool but somewhat ancient paper by Roald Hoffmann and friends. (Do not fear the theoreticalness, undergrads and synthetikers. It's an easy read--very clearly written. I'd kill to see more like this in the literature.)

I'll say first that the black PDIs they report sound really exotic and I kinda wish mine were that color.[1] One of the more interesting conclusions of the paper is that the dyes with the most substantial band-broadening in the solid state are the ones with the highest photosensitivities. Cool, eh? I won't say too much more about crystallochromy, since the paper discusses it so much more nicely than I could if I tried, so...just read it?[2]

Since--as Kazmaier and Hoffmann state--the color of these compounds depends on their crystal packing, and this derivative is a markedly different color than anything else I've made, I'd KILL to see a structure of it. Of course, crystal growing takes time, so I'll be patient.

Also, keep an eye on CBC. We're planning something REALLY COOL! We just can't tell you what it is yet. ;)

[1] Black is a super awesome color if you're trying to make solar cells. Black with significant near-IR absorption is even better. Black leather with spikes is good for BDSM and death metal.

[2] For another, more recent, nifty paper on dye aggregates, check this out. Someone covered it already. I tried to find their post, but...I read a lot, and I've forgotten who pointed it out. Care to correct my memory?

if i go too long without posting i feel lazy

...so here's a picture. Yes, it's a rather boring yellow-brown color, which means, in my lab, it must be a synthetic intermediate of some sort and not a final product. I've never seen anything that gave the little swirlies like you see here, though, which is why it deserved a picture. Unfortunately, I don't know exactly what this IS yet, but it should hopefully get shot into the GC/MS tomorrow.

It's always nice when something crystallizes on the rotavap--lets you know it's squeaky clean. I know someone here who was extremely lucky and got single x-rayable crystals from the rotavap. Wish I had awesome crystal karma like that.

Oh, and speaking of lazy, where are your entries for the lolnano contest??? We've received a few, and they're pretty funny, but they're terribly lonely and would like more friends. Yes. We require more submissions! Mwahaha!

say hello to my little friend

This week I learned that fume hoods are not invincible. The way the ones in my lab are made, there are little steel cables in the sides. If one of those cables should happen to snap...the sash will do one of two things. When this bit of misfortune befell one of my labmates, he found that his sash would move (with some effort) and then stick in whatever position he left it in if he tilted it to the side a little. Mine...well, I can pull it up (kinda heavy!) but then it goes right back down.[1]

As you might imagine, this is kinda annoying. At right is my solution: the giant 2by4 of science![2] Note the little rubber footies--these rest on the metal lip of the hood and prevent it from slipping and allowing the sash to slam down on my hands. You can't see it, but there's also a little notch in the other end to hold the sash in place.

Yay! Now I can actually reach to the back to adjust clamps without fear of being beheaded.

[1] Apparently it takes a while to get these things fixed here--unlike at other universities that actually treat their chemists like they want them there...

[2] Much thanks to Daddy for the use of his table saw.

Excimer's Adventures in the Clean Room

I've decided to chronicle my adventures in the clean room, since to many, a clean room is a thing of mystery. The layperson's only real experience with a clean room is those old Intel commercials with the bunny people. Yes, people who work in microprocessor clean rooms have to wear those things, although not the flashy technicolor ones. So, without further ado, I give you a tour of a clean room.

You might be wondering, first of all, what makes a clean room clean. It's simple- the amount of particles in the air. This particular clean room I'm showing you is a class 1000 clean room. "Class 1000" refers to the number of particles in the air per cubic foot: a class 1000 clean room has, at most, 1000 particles 5µm in size per cubic foot. As comparison, the atmosphere contains millions of particles per square foot, so a clean room chops the number of particles in the atmosphere by several orders of magnitude.

While a class 1000 or 100 clean room is fine for most patterning and lithography in an academic setting, a class 100 clean room is not sufficiently particle-free for microelectronics processing. Microprocessors are typically fabricated in clean rooms with particles/ft³ that you can count on one hand. One speck of dust on an exposed microprocessor will ruin it, so extremely stringent atmospheric and climate controls are vital. However, we don't make processors here, so the regulations are less stringent. (This clean room is mainly used for photolithography.)

So where to begin our tour? Here's the door. It keeps people not privy to the wonders of the clean room out. It is made of some type of wood, probably oak.

Once you open the door, your shoes are brushed of large particles to keep the floor of the locker room clean. In the locker room, users change into their bunny suits. The bunny suits include booties, a gown, and a cap.

Two things most people notice first when entering the clean room are 1. it's really yellow and 2. the fans are loud. The yellow color is from UV filters on the lights. Since photoresist is everywhere in this clean room, and photoresist reacts with UV light, you need UV filters. Good UV filters also block out violet light, thus the light appears yellow. The HVAC system contains ridiculous HEPA and ULPA filters to remove as many particulates as it can. The air in a clean room is changed nearly 10 times an hour- that's a lot of blowing, and so the air system is rather loud.

This is the HF hood. Hydrofluoric acid is just unbelievably nasty stuff, however, it efficiently and selectively digests silicon-based materials, so it flows like wine in this clean room. So HF work is done in its own hood. Provided are thick aprons, thicker gloves, and really thick splash guards, all designed to keep HF away from you at all times. (Good thing.)

This is a mask aligner. It exposes substrates to high-intensity UV light, to pattern substrates. I'll explain how to pattern substrates on a later post.

And this, uh... is my TOTALLY MYSPACE PIC IN THE CLEAN ROOM WOOO! Note the sexy cap, sexy gown, sexy glasses, sexy headphones (a must if you're gonna be in there for extended periods of time), and decidedly unsexy fake smile. I got funny looks from people for that pic. I probably deserved them.

...so that's my tour of the clean room. Pretty exciting. Next time I'll do a short post on photolithography.

Medusa's Silylation Reagent of Choice

First, I apologize for my blogging infrequency- I have been busy, stressed out, dejected, pissed off and making significant progress all at the same time. Seminar season is almost upon me, and you damn well better know you'll be hearing about it. I haven't posted anything recently with the F-word in it, too, so... I need to change that.

I've been working with triethoxysilane recently. It is a useful precursor to alkyltriethoxysilanes. Hydrosilylation of olefins with triethoxysilane requires a catalyst. Typically, chloroplatinic acid, H₂PtCl₆, is used, but another, far more powerful hydrosilylation catalyst, Karstedt's Catalyst (shown below), is my catalyst of choice. Catalytic hydrosilylation of terminal olefins with platinum proceeds with anti-Markovnikov addition. Karstedt's catalyst has also been used frequently in silicon-based cross-coupling reactions.


But triethoxysilane is a double-edged sword, a monster in disguise. You have to treat her with respect, or, like Medusa's gaze, she will do the following:



As it turns out, triethoxysilane and its cousins trimethoxysilane and tetramethyl orthosilicate (a useful sol-gel precursor) have this awesome tendency to form silica and polysiloxanes upon contact with water. Your eyes, by the way, have water in and on them, so you can imagine the havoc these things can wreak. (Then again, having a real, living glass eye... would be so pirate-chic.) These compounds are also volatile enough that goggles are pretty much a requirement when handling them.

Upon first seeing the label, I thought "oh fuck me, I have to use this shit, don't I?" But I am careful- I wear goggles when this stuff is open, and am pretty careful with it, and the foul beast has yet to blind me with her evil mist. Now every time I see the label, I think, "Bring it on, motherfucker."

Bring. It. ON.

The Hottest Tap Water Ever

I think I have the hottest hot tap water ever in my lab. I have to double-glove to wash anything in it because anything less scalds me. It's insane. I must be right next to the furnace, or maybe my water is heated in the fires of Hell itself. Turning on the hot water tap full blast turns the sink into a a foggy sauna and is rather pleasant as long as you avoid the superheated deluge. It's great for washing glassware, but it's a rather unpleasant experience feeling every nerve in your hands scream "GET ME OUT OF HERE OH MY GOD I AM MELTING" and you... not really wanting to obey, cause you just finished cleaning that round-bottom and involuntary responses would require breaking it. You know what I mean.

Well, like a good scientist, I busted out my trusty thermometer and checked out the hot water temperature.




That's sixty degrees Celsius, folks. Celsius. That's around 140°F, right around the hurty point of water. Actually, the water cooled down a bit while trying to take a picture of it- it was around 65°C at first- around 150°F, which is well beyond the hurty point of water. I'm not going to do anything about it, because my glassware is deliciously clean after I wash it, no doubt due in part to the scalding power of my tap water.

Sorry, lame post. But I've been pretty busy lately.

Pretty column!

Time to switch roles: usually Ψ*Ψ posts pretty colors and I write the long posts, but I think a lil' change is in order. Temporarily, anyway. (I have a serious lit post coming up, in any case. Plus, people were bitching about the lack of pictures on the last post.) Nono, it's not often I run pretty columns, but I did today. It's wonderful when you're running columns on things that fluoresce under long wave ultraviolet light (365 nm), because you can watch the things come off the column, making life a little easier. Plus, things usually fluoresce pretty violets and blues and greens. Here's a column I was in the middle of running today.

And here it is under a blacklight:


I can't tell you what it is, but I can say that it was a well-run column (a rarity- I kind of suck at running columns, and most of my stuff isn't soluble in anything, which is also annoying). Liquidcarbon also posted a purty column a while back, as did Kyle. Alright, back to work.

A Thousand Shades of Silicon

Lately, I've been working with a lot of elemental silicon in the lab. Silicon is a pretty amazing material, both in terms of its chemistry and properties as an electronic material. Its semiconductor properties make it an essential part of this blog's existence, and thus, it serves us well to pay a brief tribute to this, the element which is primarily responsible for my pejorative and pedantic blogging.

Pure silicon is beautiful stuff. Big lumps of single-crystal silicon boules have wonderful iridescent patters and reflect many different colors. Silicon wafers, after polishing, are very reflective and are usually of extreme purity: semiconductor-grade silicon, the stuff Intel and company make chips out of, is generally >99.9999% pure silicon. Silicon can be doped with other elements to enhance its semiconductor properties; for example, p-type silicon is doped with boron, and n-type silicon is doped with phosphorous. Here's a p-type silicon wafer I had lying around in the lab. Note that on the polished side, you can't even "see" the wafer itself, just the reflection. I've taken this picture Myspace-style because I am emo like that.*

Now things get a little interesting. The blue wafer on the left is silicon doped with a thin (100 nm) layer of silicon oxide (SiO₂), and the wafer on the right is pure silicon. The color of the wafer is dependent on the thickness of the oxide. This makes it easy to determine the thickness of SiO₂ on your substrate- just look on a color chart, like the one I just linked to. Why does the color change with the oxide thickness? I'm not well-versed in the physics, but Feynman knew a thing or two about it.

Silicon nitride, SiN_x, is another crystalline silicon-based network. This plate is Si/300 nm SiO₂ with some silicon nitride deposited on the surface via PECVD. The outline of the plate is purple most likely due to the lack of silicon nitride on the sides.

So, although the organic compounds I make in lab aren't as pretty as Ψ*Ψ's, the pretty silicon mirrors I use do make up for it.

*I am not a photographer. Also, taking pictures of mirrors is hard.

"how many frits have you ruined?"

Sadly, this may be the last carbon-based photo you see from me for the next two months. I'm interning in a non-synthetic environment (as opposed to A Synthetic Environment?), so I won't have nearly as many colourful organic things to show you. I may throw up some device pics, though, since that's what I'll be doing in the meantime. While I could dig up some glowing liquids I've made and not posted, or some glowing TLC plates, I figure you might be more interested in what exactly I'm doing with some of the lovely materials we've blogged about here. That, and lit posts. No one ever gets tired of lit posts, right?

Anyway, the title question is something a labmate asked when she heard I was working on a particularly insoluble class of compounds. The answer was somewhere around three or four when I finally decided to do some cleaning because I needed usable glassware.

The pic on the left shows some pretty-but-insoluble gunk embedded in a frit. This isn't good. After repeated solvent rinses, nothing would come out. That is...until I went crazy and decided that sulfuric acid was really a pretty good solvent. Plus, it turns some things a lovely magenta-to-blue colour. NoChromix is also an option, so I've heard, as is a mixture of H₂SO₄ and H₂O₂.

Yeah, I know cleaning glassware isn't exactly exciting, but I bet yours doesn't turn bright pink. And neither will mine, for the next few months. Doesn't mean I'll stop writing, though.

surprise!

Sorry, Excimer. I was going to do a post on something else, but then I got to the lab today...and found these!

Surprise crystals are maybe the best kind of surprise ever. The only thing that really comes close is surprise money...if it's more than $20.[1] Kyle did a post a while back on growing crystals, but he failed to mention the only method that has seemed to work for me thus far. See, whenever I make a conscious effort to get something x-rayable, I think my compounds realize it. And then they laugh at me and aggregate or powder out or gellate. It's a little depressing. Almost all of my intermediates crystallize if I so much as look at them funny. The things I want x-ray structures from? No cooperation whatsoever...unless I am not seriously trying.

I advocate the accidental method of crystal growing. The last thing that worked was left after a mess of solvent evaporated--it was solvent I had used to rinse the glassware I was working with. Still can't remember exactly what was in there. Then there are the pretty red things in the picture (which, since I am excited about them now, will probably give lousy data). Those came out of the first solvent I tried. I didn't think it would work. I like being wrong sometimes.

[1] "Surprise money" refers to cash you forgot about and later found in the couch, your freshly washed pants, etc.

stupid undergrad-in-lab moment

Synthetic chemistry is one of those disciplines in which there is no substitute for experience. Frequently, something arises for which there is no accepted procedure, so a high degree of resourcefulness is required.[1] No one is particularly good at it when they start (usually as an undergrad), so a few fuckups are more or less expected. Some people make more mistakes than others, and some mistakes are more serious than others. Derek Lowe has a fantastic collection of these stories, not all about undergrads, and I highly recommend that you read them.

I've been a bit on the cautious side in the lab, and I usually think about what I'm doing, so I don't have too many stories of my own to share.[2] But here is something that happened to me very, very recently. Remember my craptacular oil bath? Well, those Sonogashiras were in tiny little flasks, and the original level of oil in my bath wasn't quite high enough to effectively heat them. So I decided to add a little more. These were oil baths I'd inherited from the last guy who was in my hood, so I'd never had to fill or refill them. I knew we used PEG (poly(ethylene glycol)) for this, so I grabbed a bottle off the shelf and dumped some in, then turned up the heat a little and let it melt into the oily mess that was already there. The cute little Sonogashiras worked beautifully, but I had something else to set up that was in a 1L flask, so I poured some of the oil back into an empty bath and stuck the flask in there.

Well, after I worked that up, and the oil had cooled back to room temperature, I was confronted with this:
The PEG had solidified. What I didn't know was that the PEG we usually use for oil baths was not quite the same as the white crystalline-looking PEG that I had added to mine. When a labmate pointed out the greasy-looking carbowax PEG, I knew what I had done. The molecular weight on the correct PEG was around 600, but the crystalline stuff was around 8000. Quite a difference.[3]


[1] Often, this requires fixing things around the lab when they break. I am always looking for an excuse to break out the screwdrivers.
[2] I think being cautious drives my boss a little nuts. He's very much a cowboy chemist.

[3] For any non-chemists out there, PEG is a polymer, so the molecular weight depends on how long the polymer chain is. As the molecular weight increases, the polymer will go from liquid to glassy oil to wax to kinda-crystalline solid.

sonogashira party!

I'll start by admitting how much I love the Sonogashira coupling. It's a fun reaction, and it LOVES my substrates. Plus, it gives me an excuse to make Pd(Ph₃P)₄. Making tetrakis is one of those things you can do on a particularly bad lab day that is guaranteed to make you feel better. It's very hard to screw up, and you get shiny yellow crystals.[1] Anyway, I set three of these up the other day:

If you were wondering, yes, there appears to be a shortage of tiny little clamps in my lab. We just don't do much with 14/20 glassware (this is an exception of sorts). Maybe they're in the stockroom, but by the time I need one I'm always in the middle of setting something up, so I haven't checked. Yes, my oil bath is nasty looking. It was like that when I inherited it from the hood's previous occupant. The color reminds me of motor oil, which is a quick way to ick me out a little.[2]

Anyway, after my happy little reactions ran overnight, I had a nice little surprise waiting for me in one of the flasks:

It looked exactly like metallic copper, which it doesn't quite in the picture, but close enough. Does anyone know what it could be? I've seen palladium plate out of a reaction, but copper?[3] That just seems weird. It worked, though, so I'm not complaining.

I took all three of those through silica plugs, which was more time-consuming than I would have liked.[4] I know this is pretty routine, and barely worth reading about, but since some chemists seem to be complaining about the lack of pretty colors in their lives, I had to show mine off. (You have permission to be jealous now.) Here is one of the fractions I collected:

I know blue isn't too much to be excited about in the way of fluorescence (yeah, yeah, emission probability goes as ν³, I know, red is cooler) but it's still surprising to look at a TLC plate and be distracted by an unexpected glow from elsewhere on the bench.

[1] And then you wash them with ether. Mmm. Keeps getting better and better, doesn't it?

[2] Lest you think I'm just being girlie, I can and do change the oil in my car. But I have a texture problem with it. Ewwwwww, slimy!

[3] Pd-mirror is beautiful shiny stuff. (We at CBC like shiny things.) I wish I had a picture to show you, but I don't.

[4] Ever wonder how many YEARS of your life you've wasted staring at a rotavap?

crazy or homicidal? which is it this week?

There are labs where the gloves guard against sample contamination, and there are labs where the gloves (half-assedly) guard you against almost everything you touch. After working in a few of the former, I am now in one of the latter, but I'm a little paranoid at times. Most things I see here on a daily basis are harmful in some way or other. A little caution in handling them negates most of the risks. I've never used anything pyrophoric, though...

Non-chemists: I wanted to take this opportunity to display a few things that appeared on a box that recently arrived in our lab. Now, usually it's the label on something that has the paranoia-inducing words punctuated by exclamation marks. Danger! Toxic! Irritating dust! Carcinogen! This time, it's the box it was shipped in. (Hazmat and shipping...you know how it is.) I was particularly drawn to the "SPONTANEOUSLY COMBUSTIBLE" sticker, which could seemingly allude to spontaneous human combustion, something I will likely experience within the next week.

The backstory? I happen to be an exceptionally jumpy undergrad. So jumpy, in fact, that I had to tack up a little sign to remind the boss to make his presence known lest broken glassware and other less-than-desirable incidents ensue. (He walks so quietly that I suspect he may secretly be a ninja.) I also have a tendency to panic a little in the event of unintentional fire.[1] With these things in mind, I'm set to do a reaction involving hydrogen and the contents of the aforementioned box with frightening labels.[2] Nothing good can come of this...

Thoughts, anyone? One of my labmates has proved to be especially handy with the fire extinguisher, so it shouldn't be too bad. The real reason behind this post and the inspiration for its title is actually a certain IP that has been showing up around here. It would seem that someone has more important things to do than blog-reading...[3]

[1] Intentional fire can be fun. Unintentional fire, like uninitentional pregnancy, is generally not welcome. Ψ*Ψ is (and will remain) childfree and unapologetic.

[2] By "the contents" I mean the vial of Raney nickel in the box. The vial was not the only thing contained by the box. Some people do not appear to understand what to use in confusing situations such as this, thus the need for clarification.

[3] No disrespect intended. After all, you already indicated that the answer is "homicidal."

now accepting mojo donations

I like to take pictures in the lab. (This should be painfully obvious to anyone who has been following this blog.) Fortunately, I have a nice variety of subjects, because most of what my labmates and I make is unusually vivid. On any given day, I could walk in and find a solution for every color of the rainbow. It wouldn't be hard to mistake a random something-or-other on the rotavap for Kool-Aid.[1] It's a safe bet that most organic chemists don't see these things on a regular basis. Those who do are awfully quiet as far as blogging goes, so I'm guessing that very few people appreciate just how troublesome highly fluorescent compounds are for the camera. Granted, not everything poses this problem. If they don't absorb camera-flash, it's a non-issue.[2] This is true for most garden-variety boring white-to-yellow organics. There's also not a problem if the flash-induced glow is close to the solution colour, which is the case for the perylene diimides I've worked with.

Right now, the solution pictured above is the one that's giving me problems. I could show you the nearly-opaque red stuff I see when I turn the flash on, or I could show you the dark blue solution I see when I turn off the flash and hold it so that the light shines through it. It's almost iridescent in appearance--most of the time, it's not all blue or all red but a blend of the two. You can see this below, but the camera definitely doesn't do it justice. The camera also doesn't show just how much I've abused the TLC pencil in the picture. A bit of it remains stuck on the bench.

Photography is still a side interest of mine, though, and thus not deserving of too much complaint. The most irritating thing about the above solution is that I'm trying to grow crystals from it. I didn't know this wasn't easy. It sounded easy.[3] But I'm after sizable, high-quality single crystals suitable for x-ray diffraction. It appears that growing these is more voodoo than science.

Please share your crystal mojo. I need it.

[1] In the lab, as in any self-respecting suicide cult, those who are there of their own free will are necessarily insane. Don't drink the Kool-Aid!

[2] This has me seriously wondering about the spectrum of light emitted by camera. Most things that fluoresce under long-wave TLC lamp seem to fluoresce under camera-flash...

[3] I'm good at being wrong.

David Hasselhoff, meet No-D NMR

I don't know how well-known this particular technique is, but I have reliable sources that say it's not nearly as well-utilized as it should be, so consider this a public service announcement (since, as a blogger, I am a public servant or something). Have you ever had to titrate that old bottle of butyllithium? Kind of a pain, isn't it? There's an easier way to determine the concentration of butyllithium in solution, and it works with just about any alkyllithiums, Grignards, or anything else you decided to buy from Aldrich. It utilizes a technique called No-D NMR, and I'm sure most synthetic chemists will find it useful- nay, indispensable!

Here's what you need:
-A bottle of butyllithium in solution (essential for... finding... the concentration... of butyllithium... in solution...)
-An NMR (kids, ask your parents for $500,000 or an NSF grant!)
-An NMR tube (your NMR tech will be mad at you if you don't use an NMR tube)
-Some kind of standard with easily integrable peaks (current favorite is the cheap but stinky cyclooctadiene, affectionately known as COD)
-Ten minutes. (Just ten minutes!)

Now you can get the concentration of your butyllithium in just 6 easy steps!
Step 1. Add 600 µL of your butyllithium solution and 100 µL of COD to your NMR tube.
Step 2. Run, don't walk, to your NMR. Be sure to shove people that may or may not be in your way to really flaunt that air of urgency. (Actually, it doesn't matter. Butyllithium isn't nearly sensitive enough to ambient conditions to affect your titer.)
Step 3. Shim the NMR with the lock off. It's easier to shim the FID since the shim level is based on the deuterium lock (at least on Varian machines), and, you might have noticed, you don't have any deuterium here. (Thus the name No-D. Don't you feel smart for knowing that?)
Step 4. Set your d1 (on Varian machines. On Bruker machines, the parameter is DEUTSCHLAND ÜBER ALLES) to around 20s. This is necessary to completely relax the COD for accurate integration. Scandinavians might add a lutefisk joke here. Set the number of scans to 4-8 or so.
Step 5. Wait. Since your d1 is pretty high, it might take a while. Maybe watch the following video while you wait?
Step 6. Integrate the two COD peaks that stand out at 2.4 and 5.5 ppm. The ratios should ideally be 1:~2.03. If they're not, you fucked up. Repeat steps 3-5. Integrate the peak around -1 ppm that corresponds to two butyllithium protons. Back calculate the concentration accordingly.

And you're done! No messy Gilman doubles, one piece of glassware to clean, and an accurate titer! AND David Hasselhoff! Now go out there and titer that butyllithium! And be sure to flood the comments with boasts of how you already knew about this or how easy it is for you to do a Gilman double now that you've done it a thousand times. This IS a chemistry blog, after all.

Oh and if you're wondering about why David Hassehoff has anything to do with No-D NMR, he doesn't. I was watching that video while typing this post. Frankly, the man is a god.

no clue what it is, but it's bright

I ran a reaction the other day that ended up with a lot of byproducts. I mean, usually there's a spot or two of stuff that seems to elude reasonable explanation. This is different, though. I'm only showing a few of the last fractions here. Most organikers probably see more TLC plates than they'd like, but I'm willing to bet that most of those TLC plates don't look like mine. (Never mind the lack of glasscutting skills and inability to draw straight lines.) The camera didn't get it quite right, though: it was a little less streaky than it looks, and 18 & 19 should show a blue-violet baseline spot and a slightly higher one that's bright green.


As an added bonus, here is something that came out in a few earlier fractions. It looked like something you might expect if you put Barbie through a blender and then ran a column on the mess. Very, very pink in solution, though I'm willing to bet that the solid will look very different (and hopefully will also be nicely sized and crystalline).


This post isn't intended as a Mystery Flask. You can guess all you want, of course. I won't tell you the answer, though, since I'm still guessing too.

The Man.

Over at one of my favorite stomping grounds, ChemBark, Paul details his idea of marketing goods with famous chemists' endorsements- for example, colored chalk with Andy Myers' seal of approval on it, or, better yet, personally autographed and numbered vials of catalysts from Bob Grubbs. This reminded me that someone in our group had that idea a while back, though sadly, not much came out of it, except for some of my favorite vintage chemicals in our lab.

Now, Bob Grubbs is The Man. We all know he won the Nobel Prize in Chemistry in 2005 for his work on olefin metathesis. And granted, Grubbs' work on metathesis was revolutionary not only to organic chemistry, but also to the synthesis of new materials. I don't need to elaborate that his work has had a tremendous impact on several branches of science.

So it's not unusual for people who have a Grubbs legacy to be rather fond of The Man. My current boss worked for Grubbs, as did my undergrad advisor. There is definitely a sense of high respect for him in both groups, particularly because in my current group we do a lot of metathesis. A LOT of metathesis. We make Grubbs Catalyst Gen. 1 by the ton (and by ton, I mean I don't know how much, but it's a lot, certainly). For those not in the know, due to licensing restrictions, you can't buy Grubbs catalysts in bulk from Aldrich-if you want a ton of it you have to make it yourself or pay a lot of money. Anything ruthenium is pretty expensive (the starting ruthenium material for Grubbs, (Ph₃P)₃RuCl₂ costs about $43/g from Aldrich), so it's definitely a pricey process to run this stuff even in tens of grams. Nevertheless, we have a lot of metathesis catalysts lying around.

With all this metathesis magic in our lab, someone in our group decided to pay homage to Grubbs by putting his headshot on a few vials filled with some early ruthenium alkylidene metathesis catalysts, as a reminder to all that who use it who came first:


Truly a classy way to celebrate one of today's most distinguished chemists.

PharmTox 101 Courtesy of Fisher

Let's be honest. As synthetic chemists, we don't look much at the labels for the chemicals we buy. Aside from the important stuff (will it kill you? What's the molecular weight?) I doubt we look very much at the warning labels, cause 1. we treat pretty much all chemicals with some amount of care, and 2. everything is toxic and/or carcinogenic. So it's not often that I actually learn something from the warning labels, and I was quite surprised to be educated by a bottle of methylene chloride from Fisher while waiting for a TLC to finish:



Well, I learned something from this- well, aside from the fact that in California, everything gives you cancer. I always knew that methylene chloride was bad for you, but now I know why. Always nice to see chemical companies treating their customers like, um, scientists.

Mystery Vial!

I just did a reaction in lab with a pretty striking color change. So in keeping with this blog's tradition of (read: Ms. Complex Conjugate's obsession with) pretty colors, let's do another Mystery Flask! Well, except I do reactions on smaller scales, so it's more like a Mystery Vial.

Anyway, here's the starting material (in solution):


...and here's the product (in solution):


Some hints: The reactant and products are organic (no metals here!), and you can actually monitor the reaction by the color change. This reaction's among my favorite class of reactions. I'll probably post the answer later tonight or tomorrow.

what's in the flask:

Yesterday's mystery flask managed to confound pretty much everyone who guessed. Surprise, surprise: here's the reaction.

Here's a shot of the flask before the reaction with everything in there except the amine.

I know what you're thinking. "Dude, where's my solvent?" Everything is solid! ...At room temperature. The reaction is actually run at between 105 and 140 or so degrees, depending on the boiling point of the amine. Stick a septum on, blow nitrogen through it like crazy and inject the amine. This throws off water vapor, so pressure will build up. If you're not careful, you will hear a *POP* and rush over to see your septum off to the side. Folding it down and using a piece of wire to hold it in place seems to work well, but keep an eye on the bubbler. The lovely white crystals from yesterday's post can clog the needle.

The workup (which is simple but also a pain in the ass) and the rest of the procedure is detailled in this paper. As an added bonus, there's a bit about solar cells in there![1]

Beautiful reaction. It's never failed me. The only downside is that you should keep a LOT of chloroform handy, if you ever want your glassware to be clear instead of reddish in places.[2] Oh, and on this note, be sure to keep R long and greasy.



[1] Sadly, as is stated in the abstract, the solar cells they tried to make with these didn't quite work. Maybe sometime I'll have something to say about electrode interfaces. For the moment, though, I'd rather leave that one to the surface chemists and the engineers.

[2] Particularly if there are ground glass joints involved.