Chemists have a little mnemonic teaching rhyme which goes:
If it's blue, it's cobalt (II).
Cobalt (II) salts give the gorgeous deep blue color which contrasts the stark white tin glaze used in Delftware pottery:
Like iron, our bodies need cobalt -- just less of it. Vitamin B12, also called cobalamin, contains cobalt. Vitamin B12 fascinates me because it was present at several very important 20th century chemical mileposts. I could write a blog post about each and every of the following:
- How the discovery of liver juice and liver extracts cured pernicious anemia, leading to a Nobel Prize in Medicine in 1934.
- How after the curative factor was isolated and named Vitamin B12, British chemist Dorothy Hodgkin determined its structure using X-ray crystallography. Vitamin B12 was then the most complex natural molecule known.* Hodgkin received the 1964 Nobel Chemistry Prize for her work.
- How Hodgkin's structure inspired Robert Burns Woodward, American chemist extraordinaire, to synthesize B12 de novo. This work, his crowning oeuvre, in collaboration with Albert Eschenmoser in Switzerland, spanned a dozen years and spawned much new chemistry and also a set of rules which led to another Nobel Prize in 1981 (which Woodward would have shared had he lived).
- How the isolation of Vitamin B12 sparked a legal battle in the patent world beginning in the late 1950's: the legal question was whether something found in nature was patentable subject matter or not. Ironically, SCOTUS may be revisiting parts of a 1958 case this fall when they decide to hear arguments or not regarding the patentability of genes.
*While the contemporaneous discovery of DNA (the double helix) was perhaps more important, B12 was intellectually more interesting, involving as it did a novel cobalt-carbon bond.