Most of you remember your first organic chemistry course with great fondness. You recall the thrill and excitement of learning new reaction mechanisms and getting used to pushing electrons using those neat little curved arrows.
I can imagine your sense of pride and anticipation when you started taking your first biochemistry course and realized that you could make use of all that chemical knowledge. Biochemists also like to draw curved arrows to show you where electrons are going.
Well, you can thank this week's Nobel Laureate, Sir Robert Robinson, for those arrows. He was the first chemist to use them back in the late 1920's. The convention didn't become popular until after World War II and it only became common in chemistry textbooks during the 1950's. The curved arrows spread to biochemistry textbooks in the '60's and '70's to the delight of all biochemistry students.
Believe it or not, there are some people who are not big fans of curved arrows (Laszlo, 2002).
This short note reflects upon the widespread practice, in the classroom, of the paper tool of reaction mechanisms, taught with Lewis structural formulas, using curved arrows to denote motions of electrons. It is concluded that this practice, while assuredly improving upon the rational understanding of chemical reactions and their underlying logic, can easily become a modern counterpart to medieval scholastics. It has many of the features of slang with respect to more thoughtful and dignified speech. And it may breed cynicism and skepticism on the part of the students when they see this paper tool turned into a universal explanatory device.What a spoilsport ..... Today's students aren't cynical—they love organic chemistry. Else why would so many take it at university?
Laszlo, P. (2002) Describing Reactivity with Structural Formulas, or when Push Comes to Shove. Chem. Educ: Res. Prac. Euro. 3:113-118.
2 comments :
I know I enjoyed O Chem. The chemistry was interesting, and the professor I had was the bane of all pre-meds. If you didn't understand the chemistry, no amount of memorization was going to help you. Watching that was almost as fun as the chemistry. :-)
If you’re going to represent stable molecular eigen-states with a set of sticks connection letters of the alphabet, it’s hardly less of a parody to depict the slip and slide of a time-dependent “reaction” wave function ‘seeking’ equilibrium with a few arrowed sticks.
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