Organosulfur Materials with High Photo- and Photo-Oxidation Stability: 10-Anthryl Sulfoxides and Sulfones and Their Photophysical Properties Dependent on the Sulfur Oxidation State

While few studies show only symmetrical and poorly mono-SO (n = 0-2) substituted acenes, in this study, we present a synthesis of a new group of unsymmetrical, significantly substituted derivatives, which revealed unique photophysical properties. Both sulfides (S), sulfoxides (SO) and sulfones (SO ) showed very high photochemical stabilities, unusual for these groups, during UV-irradiation at 254/365 nm (air O and Ar), which was higher than any found in the literature. For the (S)/(SO) series (254 nm), the stabilities of 80-519 min. (air O and Ar) were found. At 365 nm, stabilities of 124-812 min./(air O ) for (S)/(SO) and higher for (SO ) were observed. Photoluminescence lifetimes of (SO ) of the lower anthryl symmetry remained in the following order: (SO ) < (S) < (SO); those with full symmetry were in the following order: (S) < (SO) < (SO ). The enhanced photostability was explained with DFT/MS/Hammett's constants, which showed the leading role of the SO groups in stabilization of HOMO/LUMO frontier orbitals. The SO (n = 0-2) substituted acenes turned out to be tunable violet/blue/green emitters by oxidation of S atoms and the introduction of rich substitution.