Post Tagged with: "Roald Hoffmann"

Molecular Strain: Make me, I dare you

Roald Hoffmann and Henning Hopf have a great new paper out in Angewandte titled Learning from Molecules in Distress. The paper is a romp through the field of “unhappy” hydrocarbon chemistry. It starts with a rationalization of the field of highly strained molecules, but quickly goes to the psychology of sadomasochism and vexing contemporary philosophical dilemmas as the Trolley problem and the Swampman.

On an aside, the Swampman thought experiment is thus,


Suppose lightning strikes a dead tree in a swamp; I am standing nearby.My body is reduced to its elements, while entirely by coincidence (and out of different molecules) the tree is turned into my physical replica. My replica, The Swampman, moves exactly as I did; according to its nature it departs the swamp, encounters and seems to recognize my friends. It moves into my house and seems to write articles on radical interpretation. No one can tell the difference.


As many of the elements in your brain get replaced within a month or so from the food you eat, this really shouldn’t be such a dire philosophical dilemma, than a common curiosity of everyday life. But I understand lightning is more theatrically appealing than a sandwich.

This is all within the context of explaining the glamorous life of the investigative synthetic experimentalist. Mission accomplished, if that was an intended goal. The paper also does discuss chemistry, and special attention was given to cyclic ozone 1, dicarbon dioxide 2, hexaazabenzene 3, and hexaprismane 4.

stressed molecules

The masochistic chemist has 2 problems with the synthesis of these types of molecules. The first is near and dear to my heart, stability. Although, these molecules lie in a potential minimum and thus are thermodynamically “stable”, they can be quite reactive with itself or other molecules within the atmosphere or the medium it finds itself in. Plus, even thermodynamic stability have qualifiers, the size of the potential well may be so shallow to never see these peculiars at room temperature, which is likely the case for hexaazabenzene.

The second problem for molecules in distress is the inability of a clear synthetic strategy to the target; these molecules are unknown for a reason. Thus, the ever enterprising physical organic chemist needs to utilize chemistry outside a pure organic chemistry approach and may have to chase these molecules down within the complexation with metals, or in low temperature inert matrixes, or even perhaps atom by atom in an STM. In any case this paper is a fun read and should definitely be shared.

Mitch

Note 1: The Hoffmann & Hopf paper: Learning from Molecules in Distress
Note 2: Paper originally covered by CBC: kinky!
Note 3: RajaLab Weblog has covered some interesting sulfur helicene chemistry: Carbon-Sulfur [11]Helicenes: Syntheses, Structures and Properties
Note 4: Also covered by selenized: the value of making things

By April 26, 2008 2 comments synthetic chemistry