2,3‐Dihydro‐2,3‐dimethylenthiophen, Dihydrocyclobutathiophen und die gegenseitige Umwandlung beider Verbindungen

Abstract

2,3‐Dihydro‐2,3‐dimethylenethiophene, Dihydrocyclobutathiophene and the Mutual Interconversion of Both Compounds The title compounds 2,3‐dihydro‐2,3‐dimethylenethiophene ( 5 ) and 1,2‐dihydrocyclobuta[ b ]thiophene ( 6 ), are generated and characterized by UV‐photoelectron ( 5 ) and UV/VIS‐absorption ( 5 and 6 ) spectroscopy. The gas‐phase equilibrium 5 ⇄ 6 is discussed. According to the photoelectron (gas phase) and UV/VIS‐absorption (argon matrix) spectroscopic product analyses only 5 is present in the gas phase. The interconversion of 5 and 6 , however, is possible in an argon matrix by irradiating with light of appropriate wavelengths.