Modulation of [8]CPP properties by bridging two phenylene units.

We report the synthesis and characterization of two new fluorophores, consisting of a [8]cyclo- para -phenylene core in which two phenylenes are bridged by either a nitrogen atom or a carbonyl group. The nitrogen bridge increases the HOMO-LUMO gap, whereas the carbonyl bridge decreases it. These results provide guidelines to control the electronic properties of nanohoops.