Synthesis and optical properties of mono- and diaminocorannulenes

The synthesis and luminescence properties of a series of mono- and diaminocorannulenes are described herein. Their synthesis from halocorannulenes is straightforward. Evaluation of their luminescence leads to three surprising discoveries. First, a wide range of mono- and diaminocorannulenes are far more fluorescent in solution than corannulene itself, and 4a-j and 5a-e are also fluorescent in the solid state. Second, we have identified a diaminocorannulene possessing what we now regard as "typical" green-yellow fluorescence in solution (λ_em = 552 nm), but exhibits orange-red fluorescence in the solid state (λ_em = 615 nm). Third, we have discovered ethylenediamine corannulene derivatives that are simultaneously water soluble and usefully fluorescent (4j, λ_em = 517 nm, QY = 9%; 5e, λ_em = 560 nm, QY = 11%). These surprising discoveries have implications for corannulene-based materials and biological applications.