A Pulse Radiolysis Study of the Formation of Dimer Radical Cations of Aromatic Olefins

The formation of dimer radical cations of several aromatic olefins has been studied by the pulse radiolysis technique. The aromatic olefins examined are 2-vinylnaphthalene (VN), 2-(1-propenyl)naphthalene (PN), 4-vinylbiphenyl (VBP), trans,trans-1,4-diphenyl-1,3-butadiene (1,4-DPB), and s-trans-2,3-diphenyl-1,3-butadiene (2,3-DPB). The formation of dimer radical cations were observed with all of them except 1,4-DPB, although it was very limited with VBP. Two types of dimer radical cations, bonded and associated ones, are formed with VN, whereas only the associated dimer radical cation is formed with PN. The influence of the aromatic substituents on the formation of the dimer radical cations is described.