Synthesis and Properties of Highly Fluorescent Indolizino[3,4,5-ab]isoindoles

Teruyuki Mitsumori (1) , Michael Bendikov (1) , Olivier J. Dautel (1) , Fred Wudl (1) , Takeshi Shioya (2) , Hideki Sato (2) , Yoshiharu Sato (2)

1 UCLA - Department of Chemistry and Biochemistry, Exotic Materials Institute, University of California, Los Angeles
2 MCC - Science and Technology Research Center

We report here the synthesis, X-ray structures, optical and electrochemical properties, fabrication of light-emitting devices, and density functional calculations for indolizino[3,4,5-ab]isoindole (INI) derivatives. Strongly luminescent heterocycles based on the INI unit were synthesized by 1,3-dipolar cycloaddition reactions between pyrido[2,1-a]isoindole (PIS) and acetylene or ethylene derivatives. They are indolizino[3,4,5-ab]isoindoles 2-9 and 14-15, benzo[1',2'-1,2]indolizino[3,4,5-ab]isoindoles 10, pyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindoles 12-13, and 2,3-hydropyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindole-1,4-dione 11. The relative luminescence quantum yield can be as high as 90%. Their reduction and oxidation potentials and high luminescence can make these heterocycles possible alternatives to tris(8-hydroxyquinolinato)aluminum (Alq3). The brightness of the light-emitting device reached as high as 104 cd/m2 and indolizino[3,4,5-ab]isoindole 3 emits beautifully blue light. The X-ray crystal structures of INI derivatives were obtained for the first time. The geometries obtained from X-ray data and density functional theory calculations shed more light on an interesting formally antiaromatic 16 system, which is divided into 10 and 6 aromatic systems. We also report a relatively easy protonation of INI, which occurs at a carbon, rather than nitrogen atom.

Domaines: Chimie organique

Teruyuki Mitsumori, Michael Bendikov, Olivier J. Dautel, Fred Wudl, Takeshi Shioya, et al.. Synthesis and Properties of Highly Fluorescent Indolizino[3,4,5-ab]isoindoles. Journal of the American Chemical Society, 2004, 126 (51), pp.16793-16803. ⟨10.1021/ja049214x⟩. ⟨hal-00177852⟩