18 December 2015

Colourful chemistry

Representing molecules and their atoms and ions using letters such as C, H and O to indicate the elements, as we do, gives a falsely complicated view of the world within us, because every chemical species is really just a combination of protons, neutrons and electrons, and all that really matters - all that controls the interactions that let us live, and think - are the varying patterns of negative charge distribution created by the exterior electrons as they are pulled and pushed around by attraction to the atomic nuclei and the repulsion of neighbouring electrons from one another. So a better, or at least more realistic, way to view the chemical world within us and the drugs we use to alter it is the rather beautiful "electron density" representation that uses colour coding to show whether regions are rich in negative charge or deficient in it or somewhere in-between

For example, appropriate for the days of festive excess, here is paracetamol (acetaminophen):

image from wikipedia.org 

The red-coded regions of a molecule are most strongly pulled towards the blue-coded regions of others, while these regions push away regions that are similar to themselves; and thus the little molecules and atoms and ions move around and interact and react to make us what we are, we think.

Yes, they make us think.

And very fine and lovely they are too.