Ultrafast transient absorption spectroscopic studies of new dumbbell-shaped platinum (Pt) systems composed of 'weight' and 'bar' chromophores

Abstract

Dumbbell-shaped metal complexes have received great attention in material science and chemistry because of their high ISC quantum yield and relatively long-lived triplet excited states. However, the working mechanism of the “weight” and “bar” moieties are unclear and vary with structure. In this paper, a novel dumbbell-shaped platinum complex (weight) connecting with TPE (bar) was synthesized and studied by employing time-resolved spectroscopy methods. In this system, the platinum complex, is designed to interfere with the rotation of TPE by Pt•••Pt and π−π stacking interactions, and these interactions also serve as a spin convertor to facilitate the ISC process. A N^C^N PtII-TPE decolorized triplet excited state was successfully detected by transient absorption spectroscopy for the first time and a room-temperature phosphorescence with a lifetime around 1404 ns was also observed.