The 147-nm photolyses of tetramethylene sulfide, tetramethylene sulfoxide, and tetramethylene sulfone

Tetramethylene sulfide, sulfoxide, and sulfone have been photolyzed with 147-nm radiation in the gas and condensed phases. Mechanisms which assume diradical intermediates are presented for the photodecomposition of each compound. The major reaction in all three cases is the elimination of ethylene by a ..beta..-cleavage of the initially formed diradical: XCH/sub 2/CH/sub 2/CH/sub 2/CH/sub 2/. ..-->.. .XCH/sub 2/CH/sub 2/. + C/sub 2/H/sub 4/. The competing ..beta..-cleavage produces X==CH/sub 2/ and C/sub 3/H/sub 6/. This second ..beta..-cleavage is less important in the sulfoxide and the sulfone than it is in the sulfide. The direct elimination of the sulfur atom, and any attached oxygen atoms, is of no importance in the sulfide and of increasing importance as the oxidation state of the sulfur atom increases. The similarity between the mass spectral fragmentation and the vacuum ultraviolet photochemistry of these compounds is noted and the possible involvement of triplet states is mentioned.