moleculeoftheday

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Coby

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August 3, 2007
CS2 is kind of a neat molecule - it's the sulfur analogue of carbon dioxide. It has more in common with other small organic solvent molecules than it does with dry ice (although it will react in some of the same reactions as CO2). Purportedly it doesn't smell at all when pure, or sort of ethereal…
August 2, 2007
Aromatic rings have 4n+2 pi electrons, where n is any integer. You don't see odd numbers of carbons in aromatic rings too often because the pattern of alternating double bonds is disrupted - if you have a cation or anion, though, odd-numbered aromatics are possible. Tropylium cation is one such…
August 1, 2007
I love old bottles of chemicals, and I've spent many a diverting hour perusing the shelves of old university faculty members' labs. Bottles used to come in pounds (or giant "ONE MOLE" sizes). Faded typewritten text, "For medical, pharmaceutical compounding, or research use" labels, yellowed paper…
July 31, 2007
Hmmm, people don't like being told not to leave certain comments. Thanks for the snark and corrections of the chemical formula. I am off banned drug-related entries for a long while again, they're just not worth the hassle, and there's plenty of worthy molecules out there. Sorry to anyone who felt…
July 30, 2007
Friday, I alluded to a chemical in the House version of the farm bill. It's calcium nitrate. Many meth cooks use a modified version of the birch reduction, which involves using an alkali metal (lithium here) in liquid ammonia. Lot of farmers use anhydrous ammonia (which is just barely a gas - put…
July 27, 2007
Like auxins, (see also) alar is a small molecule that modulates plant growth: Chemists will recognize the N-N moiety as a hydrazine, some nasty stuff (and 1,1-dimethylhydrazine is a hydrolysis product of this stuff). Back in the late '80's, there was a huge cancer scare about this stuff - and…
July 26, 2007
Cinnabar is an ore containing HgS, or mercury (II) sulfide: It's a nice red color and pretty easy to get mercury out of - you just cook it, liberating the volatile sulfur and leaving behind mercury metal (volatile too; don't try this at home). It's funny that such a unique metal was isolated so…
July 24, 2007
(Simul-blogged with The Lab Lemming - check it out.) Fluoroacetic acid is plain old acetic acid, plus a fluorine. It is a poison of some potency. Oddly, neither the "fluoro" or "acetic acid" part is associated with any general tox risks - acetic acid, as you'll see, is central to metabolism, and…
July 23, 2007
Ammonium thioglycolate is the ammonium salt of thioglycolic acid. Having a thiol (R-SH), thioglycolic acid is a decent reducing agent, particularly of disulfide bonds (R-S-S-R'). Your hair is cross-linked by legion disulfide bonds; determining whether it's curly or straight. Thanks to some…
July 20, 2007
When I first heard of sulfur hexafluoride I thought it had to be kind of nasty - it is a sulfur (VI) compound with a bunch of halogens attached (it looks if you added some water, you'd end up with dangerous HF and H2SO4!). However, like so many fluorous compounds, it is surprisingly lackadaisical;…
July 19, 2007
People did a lot of goofy stuff with regard to chemistry in the gee-whiz days of the 1940s and 1950s. In some ways it's great we've come past that, in a lot of ways it's terrible. The same generation that gave us thalidomide also gave us Chuck Yaeger. I am all for small cell phones and $10 digital…
July 17, 2007
Before the benzodiazepines (like Valium) became ubiquitous, chemists discovered that a wide array of molecules could really zonk you out. Chemists found themselves in heady times. They were isolating single molecules that had profound CNS effects - methaqualone (Quaalude), chloral hydrate (which is…
July 16, 2007
Alginic acid is a simple polysaccharide. What makes it neat is that it will form gels in the presence of divalent cations (e.g., calcium and magnesium). It's useful anywhere a biocompatible and/or edible gel is required - one well-known use is fake cherries. If you drop a solution of sugary, red,…
July 13, 2007
My Science Project Answers Your Questions. Pretty terrific. Back Monday.
July 12, 2007
It is no secret that I enjoy smelly compounds... a lot. Here's a short list of what I seem to have covered at this blog (hits for "stinky" or "smell"). I'm sure I missed some I've already written up. If I haven't covered your favorite, post a request! Stinky: Tosyl Chloride Triethylammonium Acetate…
July 11, 2007
The drought of chemical drawing software continues - here is the story. Every so often I see how Linux is doing and use it exclusively for a week or two. It is actually a usable desktop environment now, unlike a few years ago, but there isnt anything to draw decent structures. Today I set up…
July 10, 2007
Palladium is really neat stuff. It has an almost absurd affinity for hydrogen - it's one of a few metals we can use as something other than a salt or complex (i.e., just the metal). Pd on C is just carbon dust covered with 5 or 10% Pd metal (you can't see it - it's very expensive copier toner…
July 9, 2007
Potassium permanganate, or KMnO4, is one of the most well-known oxidizing agents in chemistry. Unfortunately, it's a bit like taking a gun to a knife fight... One of the big downsides of permanganate is the fact that it's a very polar ion. Crown ethers to the rescue. Permanganate is a beautiful…
July 6, 2007
Dimethylaminopyridine, or DMAP, finds general use in organic synthesis as a "nucleophilic catalyst." Its strongly donating dimethylamine group affords it substantial nucleophilicity. The adducts formed by its nucleophilic addition, however, are quite reactive - analogous to an acid chloride - so…
July 5, 2007
Aziridine, like cyclopropane and oxiranes/epoxides, is one of the simple strained three-membered rings. The strain imparts considerable reactivity. Aziridine is kind of neat - like many crazy reactive moieties, it's attracted attention for use in cancer drugs. It's also one of my favorite big…
July 3, 2007
At the blog's previous location awhile back, I covered an oligoamine; spermine - which helps to compact DNA in cells. Spermine isn't volatile enough to smell much, but a shorter amine, putrescine, is. Honestly I don't get the low MW amine thing. Pyridine smells pretty awful to me, but…
July 2, 2007
There really isn't that much to this one, but I've always loved the name, and it's really easy to make: chalcone. You can actually make chalcones with no solvent at all by just mixing aldehyde, ketone, and base in a mortar and pestle. Like Ritz mock apple pie, it's fun to try at least once, even…
June 28, 2007
Working on a bunch of paperwork tonight so just a quickie - Ritalin. Methylphenidate/Ritalin is probably the best-known ADD drug. It's just another phenethylamine - the broad class of drugs which includes pseudoephedrine, amphetamine, and MDMA. Another phenethylamine that is used in the treatment…
June 27, 2007
Cotinine is the principal metabolite of nicotine: Cotinine spends quite awhile in the body; it can take several days to eliminate, so it's a marker for recent exposure to tobacco (secondhand smoke counts). This makes it one of the few drugs other than marijuana that will reliably show up on a drug…
June 26, 2007
Bisphenol A is one ingredient that makes polycarbonate and epoxies work the way they do. A lot of people have fretted and expressed some concern about bisphenol A bioaccumulating - I can just about guarantee you're toting some around in your fat. More persistent and toxic to aquatic life is a…
June 25, 2007
One aspect of opiates a lot of people don't know about is their effect on the GI. They slow gut motility, so opiate abusers often experience constipation (and diarrhea upon withdrawal). Opium used to be used medically as an antidiarrheal medication in a tincture with camphor - paregoric.…
June 22, 2007
Henna tattoos are a pretty harmless way for hippies to entertain and adorn themselves. A relatively benign dye, Lawsone, stains the skin (or hair) a ruddy brown. Like a semi-temporary tattoo. However, you're limited to pretty much just that color. Some manufacturers have added p-phenylenediamine to…
June 21, 2007
Sorry for the Internets silence - apparently cable modems can just up and die on you. We have short memories. Ages ago, a molecule that was essentially a chimera of sugar and fatty acids was found to provide essentially no nutriment whatsoever (ironically, it was hoped it would be a rich source of…
June 15, 2007
Internets troubles. Not sure when this will be fixed, but expect posts to be irregular to absent until at least early-mid next week...
June 13, 2007
Polyphosphoric acid is a mixture of phosphoric acids and its anhydrides: I like it as an acid catalyst in organic synthesis - a lot of people hate it because it's so thick and hard to handle. The stuff is absolutely gooey mess; when you heat it up, it gets down to about the consistency of honey.…