2,7-Bis(3,4,5-trimethoxyphenylethynyl)fluorene 1 was synthesized and characterized to evaluate its characteristics as a blue emitter molecule that would and have greater photostability than its 1,4-phenylenevinylene analogue (Rathnayake, H. P. et al. Chem. Mater. 2006, 18, 560) having the same terminal groups but olefin linkers instead of alkynes. Compound 1 was synthesized by in situ deprotection and Sonogashira coupling reaction of 2 with compound 3.

1 2

3

Compound 1 has one broad absorption band at 360 nm (compared to two bands for bis(phenylethynyl)benzene oligomers and derivatives). It exhibits fluorescence at 387 nm with a shoulder at 407 nm. Its fluorescence quantum yield in acetonitrile at room temperature is 0.72. The compound exhibits electroluminescence with λ _max 473 nm and a turn-on voltage of 5 volts. Its crystal structure shows orthorhombic packing with a Pna2₁ space group. The crystallography and luminescence behavior of 1 will be compared to that of the analogue with vinyl groups in place of ethynyl groups.

We thank Dr. Ali Cirpan of the Karasz group in Polymer Science and Engineering Department for OLED fabrication and testing, and H. P. Rathnayake for providing sample compound 3.