Effect of β-Alkylthioethyl Substitution in 1,3-Dithianes: Quasianchimeric Assistance in Photoinduced Electron Transfer?
journal contributionposted on 15.08.2008, 00:00 by Roman V. Valiulin, Andrei G. Kutateladze
Nanosecond laser flash photolysis (LFP) experiments show that the rates of ET quenching of triplet benzophenone by 2-alkyldithianes significantly decrease with bulkier substitution. Introduction of sulfur at the β-position of the flexible alkyl chain reverses this trend, whereas such substitution at the α-position has negligible effect. This is rationalized in terms of the three electron two center bonds, favorable due to the formation of five-membered cyclic radical cations in the case of β-substitution, which is supported by DFT computations.