Synthesis and photophysical properties of dihydroheptacenes: New blue-emitting materials

7,16-Dihydroheptacenes (1-3) substituted at the 6, 8, 15, and 17 positions are synthesized as blue emitters potentially useful in organic light emitting diodes (OLEDs). The photophysical properties of 1 - 3 ( lambda(max) = 424- 428 nm, Phi(F) = 0.15- 0.21, tau(F) = 2.35 - 2.67 ns in CH2Cl2) are discussed. They are shown to be stable and efficient blue emitters in the solid state (Phi(F) = 0.37 - 0.44). The X-ray crystal structure of 1 is reported.