Matrix Photochemistry at Low Temperatures and Spectroscopic Properties of gamma-Butyrothiolactone

DUGARTE JIMÉNEZ, NAHIR JERELY; ERBEN, MAURICIO FEDERICO; ROMANO, ROSANA MARIEL; GE, MAO-FA; YAO, LI; DELLA VÉDOVA, CARLOS OMAR

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Año: 2010 vol. 114 p. 9462 - 9470

1089-5639

The five-membered heterocyclic γ-butyrothiolactone was isolated in low temperature inert Ar matrix and the UV-visible (200 ≤ lambda ≤ 800 nm) induced photochemistry was studied. On the basis of the IR spectra, the formation of ethylketene (CH3CH2CH=C=O) was identified as the main channel of photodecomposition. The valence electronic structure was investigated by He(I) photoelectron spectroscopy assisted by quantum chemical calculations at the OVGF/6-311++G(d,p) level of theory. The first three bands at 9.54, 9.69 and 11.89 eV are  assigned respectively to the sulfur and oxygen lone pairs and "pi"CO orbitals, denoting the importance of the SC(O) group in the outermost electronic properties. The conventional ring strain energy was determined to be 3.8 kcal mol–1 at the G2MP2 level of calculation within the  hyperhomodesmotic model.