Carborane-Induced Excimer Emission of Severely Twisted Bis-<i>o</i>-Carboranyl Chrysene
Marsh, Adam V.; Cheetham, Nathan J.; Little, Mark; Dyson, Matthew; White, Andrew J. P.; Beavis, Peter; Warriner, Colin N.; Swain, Anthony C.; Stavrinou, Paul N.; Heeney, Martin
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
2018
The synthesis of a highly twisted chrysene derivative incorporating two electron deficient o-carboranyl groups is reported. The molecule exhibits a complex, excitation-dependent photoluminescence, including aggregation-induced emission (AIE) with good quantum efficiency and an exceptionally long singlet excited state lifetime. Through a combination of detailed optical studies and theoretical calculations, the excited state species are identified, including an unusual excimer induced by the presence of o-carborane. This is the first time that o-carborane has been shown to induce excimer formation ab initio, as well as the first observation of excimer emission by a chrysene-based small molecule in solution. Bis-o-carboranyl chrysene is thus an initial member of a new family of o-carboranyl phenacenes exhibiting a novel architecture for highly-efficient multi-luminescent fluorophores.