A Series of D-A-D Structured Disilane-Bridged Triads: Structure and Stimuli-Responsive Luminescence Studies

A series of sigma-pi extended octamethyltetrasilanes, which have phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, or phenoxazine (1, 2, and 3) groups as donor moieties and thienopyrazine or benzothiadiazole (a and b) groups as acceptor fragments, has been prepared, and their optical properties have been studied as an extension of our work. All six compounds exhibited fluorescence in the solid state with maximum wavelengths centered in the range of 400 and 650 nm upon excitation by a UV lamp. Compound 2b showed apparent dual emission behavior in solution, which depends on solvent polarity, and a reversible photoluminescent change under mechanical and thermal stimuli in the solid state. Quantum chemical calculations suggest the contribution of a quasi-axial conformer of the 9,9-dimethyl-9,10dihydroacridine moiety in 2b to the dual emission in solution and the mechanofluor-oluminescence in the solid state, similarly to 1a. These studies provide new insight into the preparation of disilane-bridged triads capable of responding to multiple stimuli.

Automated summary

A series of octamethyltetrasilanes with different donor and acceptor groups were prepared and their optical properties were studied. Two compounds showed dual emission behavior in solution and reversible photoluminescent change under mechanical and thermal stimuli in the solid state.