Oligothiophenes Nano-​organized on a Cyclotetrasiloxane Scaffold as a Model of a Silica-​Bound Monolayer: Evidence for Intramolecular Excimer Formation

Excimer formation in a new class of terthiophene-based fluorophores covalently bonded to a cyclotetrasiloxane scaffold has been demonstrated and the photophysical process ruling it has been investigated in detail and modeled theoretically. In contrast to the conventional systems in which long-living fluorophores such as pyrene are linked in the same molecule, an excimer is formed only when two terthiophene- based branches nano-organized on the same cyclotetrasiloxane scaffold are close enough together when excitation takes place. In such a case, excimer formation is extremely efficient, and the new bound excited states are quite stable.