Periodic Reporting for period 1 - COLDOC (Cold Organic Chemistry)
Période du rapport: 2022-09-01 au 2025-02-28
Reactions have physicochemical barriers that impede their progress. Catalysts are ubiquitously used to overcome many of these. Heat is also often applied to speed up reactions thanks to the increased motion of particles and their increasing number of collisions. In the far reaches of space and extreme cold, organic molecules are formed without this assistance. One theory is that a combination of quantum-mechanical tunnelling (QMT) and novel reactions with exceptionally low barriers could be the key. The EU-funded COLDOC project is evaluating this hypothesis through investigations that will reveal how QMT controls chemical reactivity and selectivity. This will be complemented by organic synthesis under cryogenic conditions for select compounds of interest.
This project undertaken, and achievements realized concern organic chemical reactions at insufficient ener¬gies (typically cryogenic conditions, hence the acronym COLDOC). As many organic molecules have been discovered in space or brought to earth in meteorites, they must have formed under such conditions through hitherto largely undisclosed mechanisms. One key hypothesis is that quantum-mechanical tunneling (QMT) and novel reactions with exceptionally low barriers are at work. Hence, one of the key objectives is to uncover how QMT, where reactions occur through and not over barriers, controls chemical reactivity and selectivity (in a very general sense). A second target is the preparation and examination of enols of prebiotic relevance, in particular, the enols of simple carboxylic acids, and their subsequent reactivity. Our methods include organic synthesis of starting materials and products, infrared as well as ultraviolet/visible matrix-isolation spectroscopy, ab initio computations of structures, spectra, and potential energy surfaces as well as QMT rate calculations.
The work on the intrinsic barrier width has been presented at APATCC-10 in Quy Nhon, Vietnam, and has received excellent feedback.