moleculeoftheday | December 12, 2007So people gush over bmim and get the guaranteed publications for including "ionic liquid" in the title of their article. Ionic liquids are far from the newest fad, though, they've been around for nearly 100 years!
93 years ago, Paul Walden reported that ethylammonium nitrate actually melts just north of room temperature. Ionic liquids are hot now, but did you know they were about a century old?
moleculeoftheday | December 11, 2007Most metal ions will coordinate some electron-rich species in solution - water is a common suspect. Many other things can be hung off of certain metals, however, and an entire field and fame and fortune are available to those who manage to make something useful involving a metal. "Inorganic chemistry" is really a field unto itself - organic and biochemists make use of it, but we don't really understand it.
To that end, here's something we use to condense DNA. Cobalt (III) hexamine, or Co(NH3)63+. It actually hangs onto six molecules of ammonia, and they're "exchange inert" - you can put the…
moleculeoftheday | December 6, 2007About 80 years ago, a scientist [pdf] wanted to learn about cholesterol metabolism. He took chicken feed and extracted it with organic solvent. In order make sure fat-soluble vitamins weren't left out, he added in cod liver oil (giving vitamins A and D, which were known). Then his unsuspecting chicks munched on cholesterol-free, cod-liver doped feed. Within weeks, they began hemorrhaging, and their blood failed to clot.
It was already known at the time that animals could synthesize cholesterol all on their own - and just to prove nothing was up, he added cholesterol back into the feed. No…
moleculeoftheday | December 4, 2007Anaesthetics are weird. Much of what we use has a paucity of the oxygens and nitrogens that seems to make most drugs work, and there's been substantial puzzlement and handwringing over exactly how some of these things work. Xenon, for example, is a fine anaesthetic that is, of course, comprised of a single atom. Similarly, highly halogenated molecules that are otherwise uninteresting are common.
Propofol is used in an IV emulsion (an intimate, homogeneous mixture of water and oil, like ranch dressing, or GOJO). The milky color of the product is the origin of the nickname in the title - "Milk…
moleculeoftheday | December 3, 2007When you take organic chemistry, you learn about methyl iodide for putting on a methyl group. Eventually, though, if you stick with chemistry, you need an alkylating agent for grown-ups.
There's a lot of good ones, including dimethyl sulfate, methyl triflate (PDF), and the ever-so-toxic "magic methyl," methyl fluorosulfonate.
Part of being a grown-up, though, is settling down with an alkylating agent, and aside from the odd dirty weekend with some of the more exotic compounds, it's trialkyloxonium salts for me:
We used to have coffee together in the morning, but the methanol got to me...
moleculeoftheday | November 30, 2007A lot of science-fiction writers have spent a lot of time and energy hypothesizing silicon-based life. This isn't completely insane - if you go down a column of the periodic table, stuff tends to be the same. Fluorine, chlorine, bromine, and iodine all share properties, and so do carbon, silicon, germanium, tin, and lead. Some properties.
Silane, SiH4, is the silicon analogue of methane, CH4. Not nearly the same, though - it flames in air and burns to become sand - SiO2, which is just the silicon analogue of CO2, which is a gas!
An element's chemistry is defined by its interactions with other…
moleculeoftheday | November 29, 2007DDQ is a benzoquinone derivative with some electron-withdrawing substituents, making it a bit more potent:
It's a bit more soluble than stuff like KMnO4, but not by much - it's a nightmare to work with.
moleculeoftheday | November 27, 2007In many parts of the world, what Westerners would call "meat alternatives" are the main source of protein. One such product is tempeh, made from soy. A particular variety, when contaminated with a particular bacterium, can become contaminated with a potent toxin: bongkrek acid.
Bongkrek acid, like dinitrophenol and cyanide, is a mitochondrial poison.
moleculeoftheday | November 20, 2007Marijuana is a puzzling drug, and a contentious one at that. Pure THC is sold pharmaceutically (and DEA-OK), but the whole plant isn't OK with the feds. That said, many states have decriminalized it for medical use. The pharmacology of cannabinoids is complex; marijuana aficionados report the drug exhibits a certain capacity to make eating 99 cent frozen pizza a more sublime experience than it would be sober. This rationale has resulted in the use of rimonabant, a cannabinoid antagonist (that is, it blocks its effects, like yesterday's molecule does with nicotine) to treat obesity.
Currently…
moleculeoftheday | November 19, 2007Smoking cessation is tricky business - most of the time, people have used nicotine replacement therapy (the patch, the gum, etc) or CNS active drugs (like Wellbutrin/Zyban/Bupropion). None of it works that well - the manufacturers of today's molecule, Chantix, considered it news to brag about when its patients managed to quit smoking at 44% over 12 weeks (vs 18% for placebo recipients).
Chantix, however, works on a different mechanism, so it's at least notable. It's a partial agonist-antagonist - that is, it tickles the relevant receptor a little, but also blocks action at that receptor. In…
moleculeoftheday | November 15, 2007Amino acids impart lots of functions to proteins, and a lot of the interesting chemistry happens at a few residues. Many hydrophobic residues like valine and leucine play a huge role - they don't like to touch water, and they help the protein fold, but the heavy lifting of catalysis happens in just a few reactive places. Two of these are cysteine, and its rare brother, selenocysteine.
Going down the periodic table, things at once change and stay the same. A chlorine will act a lot like a bromine, which will act a lot like an iodine, but there are distinct differences in how they react. Just…
moleculeoftheday | November 14, 2007Ethylene glycol dinitrate is simply the dinitrate ester of ethylene glycol - putting glycol under the same reaction conditions that yield the primitive nitro explosives, like nitroglycerin or TNT, yields this compound. Why's it important? It has a decent vapor pressure.
The volatility allows the compound to be detected by dogs and those machines they use at the airport. While it's explosive, it has nowhere near the destructive power of what it's mixed with. Manufacturers add it (and similar compounds, lately) to their explosives as a so-called "taggant." It doesn't affect performance, but it…
moleculeoftheday | November 13, 2007Valencene is a citrus odorant found in the Valencia orange, hence its name:
It is a terpene, a motif that's ubiquitous in natural products.
moleculeoftheday | November 9, 2007I hadn't heard of this one before today: Mutagen X.
Mutagen X is apparently a byproduct of water chlorination, which isn't so surprising - chloroform (CHCl3) can occur in chlorinated water. This MX stuff is much worse, apparently. Anyone know the immediate source of the carbon?
moleculeoftheday | November 7, 2007There are a lot of stories bouncing around about a toy in Australia, Bindeez, which are apparently little beads that adhere to one another when you wet them. There are a ton of news sources getting very confused, but Reuters seems to have gotten it: they are contaminated with 1,4-butanediol, which your body metabolizes into GHB (a banned so-called "date rape drug.")
Humans evolved in the presence of ethanol - beverage ethanol is recent, evolutionarily speaking, but much of life creates a little bit of ethanol. It'd be much more toxic than it is if we didn't have a set of enzymes to deal with…
moleculeoftheday | November 5, 2007As I've mentioned in the past, chemists often need to reduce a molecule by adding hydrogen. A medicinal chemist might get to an azide by way of an amine, or a food chemist might want to get to a saturated fat (or, although it's less and less popular, a trans fat).
Adding hydrogen can be done with a catalyst and, well, just hydrogen gas. It's a gas and flammable under a huge range of concentrations. Even gasoline only burns in a narrow range in air - don't go sticking a lit stick in your gas tank, but it would just snuff it out. This is why molotov cocktails work. The gas-soaked rag will burn…
moleculeoftheday | November 1, 2007I've already talked about lead acetate and the fact that it was almost certainly the first artificial sweetener before, and I've been reading about it again lately. Here's something I didn't know - it may have helped cause the fall of Rome.
Here's how it worked. Roman households loved a condiment called defrutum - a reduction of grape juice or crushed grapes, sort of a demi-glace. The syrup, like molasses or honey, was used as a source of intense sweetness that wasn't prone to spoiling like fruit.
Grape juice, like any other acidic liquid, will dissolve a small amount of many metals - copper…
moleculeoftheday | October 30, 2007Lutein is just another carotenoid - like the previously covered retinal, it is a terpene.
Long, huh? That chain of alternating double and single bonds affords it its wonderful color. It, like retinal, plays a role in vision. The halloween angle is because it's one of the pigments in your pumpkin making it orange. The brilliant oranges and rust colors you see in nature tend to be thanks to carotenes.
In fact, as the leaves are changing (although it's not a great fall for this in much of the US), you're seeing the carotenes show their color as the chlorophylls fade away. In this beautiful…
moleculeoftheday | October 26, 2007Mercury dissolves many metals. Put a little on normally steadfast aluminum and it will slowly eat it away. Mix it with some silver, copper, and other metals, and you've got a dental filling. Mix it with sodium, and you've got a great reducing agent.
Sodium amalgam acts much like sodium, but it's got the added advantage of being a liquid - since reactions require collisions, you're not limited by the small surface area of a solid. Paradoxically, it's actually a little safer and less explodey than sodium. Unfortunately, the mercury part makes it a bit of a liability for, say, pharmaceuticals or…
moleculeoftheday | October 25, 2007The term "rare earth metal" is a misnomer that's just stuck around. They haven't been rare for years - take this ad material from about 50 years ago at Theodore Gray's excellent Periodic Table Table site.
Didymium is a mixture of rare earth metals, which, when compounded with glass, imparts some color. Metals used to be pretty much our only way of imparting color. For quantum mechanical reasons, the enormous middle swath of the periodic table can impart some brilliant colors.
Modern organic dye technology has advanced like crazy, but metals are alive and well. Your green and brown glass have…