Carborane‐Induced Excimer Emission of Severely Twisted Bis‐o‐Carboranyl Chrysene

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. Können Carborane Excimere induzieren? Die Anknüpfung von o‐Carboran‐Einheiten an Chrysen verursacht eine starke Verdrillung des aromatischen Rückgrats und schränkt die Carboran‐Rotation ein. Diese ungewöhnliche Geometrie führt zu lokalisierter (LE), aggregationsinduzierter (AIE) und Excimer‐Emission. Letztere liefert das erste Beispiel für eine Excimer‐Spezies, zu der ein Carboran elektronisch beiträgt.