New 3pi-2Spiro ladder type phenylene materials: synthesis, physicochemical properties and applications in OLEDs

International audienceNew routes towards ladder type phenylene materials 1 and 2 are described. The oligomers 1 and 2, which possess a "3π-2spiro" architecture, are synthesised using extended diketone derivatives 3 and 10 as key intermediates. The physicochemical properties of the new blue light emitter 2 were studied in detail and compared to those of the less extended 1. Due to the recent development of fluorenone derivatives and their corresponding more conjugated analogues as potential Electron Transport Materials (ETM) in OLED and as n-type materials for photovoltaic applications, we also report herein the thermal, optical and electrochemical behaviour of the key intermediates diketones 3 and 10. The application of dispiro 2 as new light emitting material in Organic Light Emitting Diodes (OLED) is finally reported