This was first posted on February 10th 2009. It’s an issue that’s just cropped up again in 3rd year projects!
That is the chemist’s question, this chemist anyway. In much the same way that one pays for food in a restaurant because the chef has added value by cooking and combining raw ingredients, a chemist’s essential job is to add value to basic chemicals through syntheses or novel applications. If only it were that simple.
Polyhedral Oligomeric Silsesquioxanes (POSS) are a perfect example of the chemist’s dilemma. These are cages of silicon and oxygen, a silicon on each corner and bridging oxygen. As silicon can have four substituents, the empty site is an organic group. I’m particularly interested in the cubic versions of these.
The synthesis of POSS cubes is a perfect example of adding value to simple chemicals. You can buy the starting materials quite cheaply, but many of the reactions are low yielding (20 %) and take a long time (1 – 3 months). There isn’t a great deal of effort involved because you put the reaction on and leave it until beautiful crystals form and can be filtered out. There are other ways but not always to the particular molecules I need.
I make them, but I could buy them. The price is not unreasonable, and I would be more or less guaranteed a certain quantity of product without stirring several litres of acetone solutions for several weeks. There would also be some quality standard in their manufacture, which would be reassuring given that sometimes the synthesis can go a wee bit wrong. I could also order some tomorrow and have it delivered by the end of the week: a far cry from 6 weeks of patient crystal watching.
Make or buy, make or buy. I’m not the first chemist to come up against this dilemma, and I wont be the last. There are many reasons to make your own. The time and precursor cost may be significantly less than the purchase price. The chemical may be particularly sensitive to degradation or fickle to store – fresh may well be best. There may be an educational benefit for a student to make something. There are many reasons to buy it in, particularly if cost is not an issue, or if time is an issue. It’s just something that needs to be weighed up.
Of course, I’m interested in these molecules because I want to do more with them, I literally want to make molecules that money can’t buy. I want to make sure that I start with the best possible materials.
Is there a comparable dilemma in bio-research? Do you worry about growing or buying cells, or purchasing kit reagents rather than making your own? What about other disciplines?