Photolysis and thermolysis of (iodomethyl)cyclopropane: Rapid ring opening of cyclopropylcarbinyl via heavy‐atom tunneling?. (14th October 2021)

• Record Type: Journal Article
• Authors: Schleif, Tim; Sander, Wolfram
• Is Part Of: Journal of physical organic chemistry. Volume 35:Number 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-14
• Subjects: heavy‐atom tunneling -- matrix isolation -- organic radicals; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.4295
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: UV photolysis of (iodomethyl)cyclopropane yielded 3‐buten‐1‐yl instead of cyclopropylcarbinyl, the expected product of photolytic C‐I bond cleavage. This result suggests that the ring opening of the intermediate cyclopropylcarbinyl even at T ~10 K proceeds too fast to be measured via this technique. This finding is in agreement with earlier theoretical studies which predicted the rapid decay of cyclopropylcarbinyl via heavy‐atom tunneling. In an attempt to rule out the potential of secondary photochemistry enabling the ring opening, flash vacuum thermolysis experiments were also performed. However, those resulted in butadiene as sole product, in both its thermodynamically favored trans ‐ and the higher‐energy gauche ‐conformation. Abstract : UV photolysis of matrix‐isolated (iodomethyl)cyclopropane yielded the ring opening product 3‐buten‐1‐yl, while flash vacuum thermolysis resulted in the formation of 1, 3‐butadiene. These results likely hint at the rapid decay of the intermediate cyclopropylcarbinyl via heavy‐atom tunneling, while also providing important reference data, for example, for combustion studies or astrochemical investigations of the C4 H7 potential energy surface.