Working chemists would much prefer to be left to their own devices to come up with names for the compounds they discover. Names that trip off the tongue, names that twist it.
Names that honour colleagues, the famous, home towns and occasionally slime moulds are all much nicer than sticking to the rules. So what's in a
name? as the man asked, and why shouldn't we keep it trivial?In the year of writing, the Chemical Abstracts Service added thousands more chemical substances to its database of almost 30 million, which averages almost half a million new molecules each year since the registry was started in 1957. Each compound is assigned a unique registry number, a simple task, presumably.
The numerical identifier, the registry code, allows scientists trawling the literature, and the Internet through services such as Chemfinder, to pinpoint an exact chemical structure. CAS, bless it, also does the really dirty job of providing a unique systematic name for each of those compounds. From this name a reasonably competent chemist should be able to work out the formula and so get a picture of the molecule.
Things are never so simple though and while CAS uses one set of nomenclature rules adopted by the American Chemical Society and other learned bodies for entries in the registry the International Union of Pure and Applied Chemistry opts for a different measure of the molecule and subsequently organisations such as the UK's Royal Society of Chemistry follow and help decide the IUPAC rules.
As every undergraduate, hard done to CAS employee and assistant editor on the chemical journals knows, naming a new compound is no simple task. Occasionally likened to puzzling over the infamous Times Crossword, chemical nomenclature is a holy vocation full of righteous fulfilment and a feeling of well being. Or, a total pain in the neck and a waste of scrap pads and pencils depending on your stance.
What's the answer? Chemists have known for years: trivial names are the
clue. Why bother rifling through page after page of blue, red and green
books and CAS directories and rulebooks when you can simply come up with
something suitable off the top of your head and have done with it. The
earliest alchemists didn't seem to worry too much about cyclic molecules
with names to set you spinning, such as
{4,34-dimethyl-1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58- icosaazatricyclo[56.2.2.2.2.2.7,10,28,31,37,40]
hexacontane}
when they had phlogiston and philosopher's wool (sic) to play with. When
it comes to trivia chemists can let their imaginations run wild.No one would imagine you could be arrested for snorting 3-benzoylmethyl-2-tropanecarboxylic acid through a short piece of tubing, but if you refer to this clinical-sounding white powder by its trivial name of cocaine, you would be a little more wary about what enters your olfactory passages. Numerous pharmaceuticals and drugs of abuse can cause a major headache when it comes to providing them with a standardised name. Take two "ortho-<I>O</I>-acetylsalicylic acids and see if you feel better.
Some of the things we eat can be a bit of a mouthful, the artificial sweetener saccharin, or 1,2-benzisothiazolin-3-one 1,1-oxide leaves a bitter aftertaste when you label it systematically. You may even try a tasty sandwich compound but would you spread linoleic and myristic acid on your bread unless you were certain they were two of the polyunsaturated fats in butter.
Many of those millions of chemical substances in the CAS system lend themselves to trivialising simply because of the things they do or the way they look. Multidentate chelating agents such as the crown ethers have a bit of ethereal character and are shaped like coronettes. Other members of this group of chemical hosts have been
given names to reflect how well they can trap their guests. The names of
cryptands, sepulchrands and cavitands all have a deathly ring to them
although their "proper" names would not sound quite so fearsome despite
taking you to the graveyard shift just to work them out.One of the brightest chemical stars to receive its name, rank and serial number in the CAS registry has to be the truncated icosahedral C60 molecule. Named for the architect, Richard Buckminster Fuller, who designed the huge geodesic structures for Expo '67 in Montreal, the C60 molecule has a thankfully succinct systematic name: [60]fullerene, which on this occasion is actually shorter than its trivial name of buckminsterfullerene. Things become slightly more complex once the chemists begin attaching things to it. After all, how do you know where to start counting from on a ball?
Some chaotic molecules known trivially as the starburst dendrimers come a little way down to earth as cascade polymers. These three-dimensional divergent molecules branch from a core and are finding themselves the centre of much attention as potential mimics of biomolecules, such as proteins. The reader is invited to provide systematic names using IUPAC rules for each and every one of those in the CAS registry. Please don't send us your answers though.
Trivial monickers often serve more of a purpose than glorifying architects or reminiscing about tombs. Classes of enzymes are generally names following simple rules to help the biochemists
and molecular biologists. The name might even hint at what a particular
enzyme does. For instance, horse liver alcohol dehydrogenase one might
correctly deduce is from the lobal abdominal glandular organ of an
equine beast and converts organic hydroxy residues to a ketonic
grouping.In a similar vein, the steroidal hormones that course through our bodies at various stages of our lives would not so much course as trickle with their full systematic names. Much more fluid are the likes of pregnenone and testosterone. Again, their names are amenable to a degree of interpretation as to their function.
It is easy to criticise the usage of systematic nomenclature but without it very little chemistry would get done. Imagine having to think of a unique, succinct and sexy name for every one of the 13 million plus substances around. Trivia has its place, especially in an emergency when one needs to know which bottle to pour over the hazard to neutralise it without having to look it up in Chemical Abstracts first. And acetone will always be acetone no matter how many technicians you try to convert. However, there is simply no substitute for a systematic procedure for identifying a particular compound uniquely and providing in that name all the information any chemist would need to know exactly which compound was being discussed. And, after all there's always someone around, usually an assistant editor on a chemistry journal, who quite likes doing crosswords.