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Abstract Science?

Abstraction, not just mathematics, has its place in science as it does in art

Roald Hoffmann

What Can Chemistry Be Against?

To be abstract, chemistry might thus have to be oppositional. But opposed to what? Nature, of course. Much good chemistry comes from imitating nature, because this ultimate tinkerer has been at it for a long time. At a chemical level in the biological universe, there is an almost bizarre seizing upon anything that works, and subsequent perfection of it by evolution: Here oxygen is carried by a red blood cell’s heme group with iron (as in mammals), there it’s a binuclear copper complex (as in mollusks and arthropods). So nature, among other things a chemist with lots of time on its hands, has found some effective strategies for making molecules and using their properties. It provides a “literature” that’s worth reading, not exterminating.

Chemists in the laboratory are torn between emulating nature and doing things their own way. A protein, through its own curling and its tool kit of sidechain options, shapes a pocket where, say, a molecule with only right-handed symmetry fits. But it not only fits, it has something done to it—a specific bond in that molecule is cleaved, or an atom is delivered to it. The chemist’s fun, much like abstract art, is in achieving the same (why not better?) degree of shape control that nature does, but doing it differently, perchance better, in the laboratory.

Protein to deliver hydrogenClick to Enlarge ImageHere’s an example, in the form of effective and specific delivery of hydrogen to an organic molecule. Nature does it, but Thomas R. Ward at the University of Basel in Switzerland and his coworkers have done it as well. As shown below, they attached a reactive inorganic piece (that’s the Rh with its ligands) through a binding link (biotin, a type of B-vitamin) to a small “handed” protein (streptavidin). The latter is the equivalent of a baseball glove; the Rh piece a very lively deliverer of hydrogen, firmly ensconced inside. The close bond leads to a strongly “handed” chemical reactivity.

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