RT info:eu-repo/semantics/article T1 A butterfly motion of formic acid and cyclobutanone in the 1:1 hydrogen bonded molecular cluster A1 Evangelisti, Luca A1 Spada, Lorenzo A1 Li, Weixing A1 Blanco Rodríguez, Susana A1 López Alonso, Juan Carlos A1 Lesarri Gómez, Alberto Eugenio A1 Grabow, Jens-Uwe A1 Caminati, Walther K1 Physical chemistry AB Upon supersonic expansion, formic acid and cyclobutanone (CBU) form a molecular cluster in which the two constituent molecules, linked by OH⋯O and CH⋯O hydrogen bonds, undergo a rapid interconversion between two equivalent forms. The tunneling motion takes place through the rupture and reformation of the C–H⋯O hydrogen bond between the carbonyl oxygen of HCOOH and one of the two hydrogen atoms of the methylenic group adjacent to the cyclobutanone keto group. From the microwave spectra, tunneling energy splittings (ΔE01) have been determined for the parent (1122.756(3) MHz), DCOOH⋯CBU (1084.538(1) MHz) and HCOOD⋯CBU (1180.282(4) MHz) isotopic species. From these splittings, the potential barrier to interconversion has been calculated to be B2 = 39.7(5) cm−1. The tunneling pathway is an asymmetric butterfly-like motion between the two moieties of the adduct, with a barrier at a configuration in which the ring plane of cyclobutanone is coplanar with formic acid. PB Royal Society of Chemistry SN 1463-9076 YR 2017 FD 2017 LK http://uvadoc.uva.es/handle/10324/21845 UL http://uvadoc.uva.es/handle/10324/21845 LA eng NO Physical Chemistry Chemical Physics, 2016 NO Producción Científica DS UVaDOC RD 08-ago-2024