Sulfur-bridged chromophores for photofunctional materials: using sulfur oxidation state to tune electronic and structural properties

The use of a heteroatom, such as sulfur, as a linker or bridge, in π-conjugated materials has advantages over purely carbon-based ones due to the accessibility of higher oxidation states as a result of hypervalence. Materials containing a sulfide bridge (S) can be systemically oxidized into sulfoxides (SO) and sulfones (SO2), each of which can then influence how a material interacts with light, playing a large role in dictating the photophysical and sometimes photochemical properties. In this perspective, we summarize the progress that our group and others have made, showing how oxidation of a sulfur bridge in symmetric bichromophoric dimers and in diimine ligands can influence the excited state behavior in organic π-conjugated materials and metal complexes.

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-SOn (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 (SO2) showed very high photochemical stabilities, unusual for these groups, during UV-irradiation at 254/365 nm (air O2 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 O2 and Ar) were found. At 365 nm, stabilities of 124-812 min./(air O2) for (S)/(SO) and higher for (SO2) were observed. Photoluminescence lifetimes of (SOn) of the lower anthryl symmetry remained in the following order: (SO2) < (S) < (SO); those with full symmetry were in the following order: (S) < (SO) < (SO2). The enhanced photostability was explained with DFT/MS/Hammett's constants, which showed the leading role of the SOn groups in stabilization of HOMO/LUMO frontier orbitals. The SOn (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.

Lophine and pyrimidine based photoactive molecular hybrids. Synthesis, photophysics, BSA interaction and DFT study

New photoactive molecular hybrids containing both lophine and pyrimidine moieties as optical sensors.

Theoretical and experimental study of the ground and excited states of 1,4-dihydropyridine based hexahydroquinoline derivatives achieved by microwave irradiation

The photophysical study indicates ICT state for 1,4-dihydropyridine based hexahydroquinoline derivatives.