Synthesis and fluorescence emission behavior of novel anti-[2.n](3,9)phenanthrenophanes

Novel syn- and anti-[2.n](3,9)phenanthrenophanes (n=3,4) were successfully prepared by the intramolecular [2+2] photocycloaddition of α,ω-bis(3-vinyl-9-phenanthryl)alkanes. The anti-isomer of n=3 was found to give excimer fluorescence in spite of the only partially overlapping phenanthrene rings, although that of n=4 gave monomer fluorescence.