Synthesis and properties of cyclic ethylene-bridged 3,6-fluorene dimer and its linear analogues

Three oligomers of ethylene-bridged 3,6-fluorene were synthesized starting from phenanthrenequinone. McMurry reaction was applied to synthesize the cyclic compound. Horner–Emmons reaction was used to synthesize the linear compounds with all-trans configuration. The crystal structure of the cyclic compound was described. The optical and electronic properties of these compounds were fully characterized and compared.