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

• Published in: Chemistry : a European journal Vol. 15; no. 46; pp. 12791 - 12798
• Main Authors: Mróz, Wojciech, Bombenger, Jean Philippe, Botta, Chiara, Orbelli Biroli, Alessio, Pizzotti, Maddalena, De Angelis, Filippo, Belpassi, Leonardo, Tubino, Riccardo, Meinardi, Francesco
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 23.11.2009; WILEY‐VCH Verlag; Wiley
• Subjects: Chemistry; Chemistry, Multidisciplinary; excimers; luminescence; nanostructures; Physical Sciences; Science & Technology; siloxanes; thiophenes; POLYMERS; thiophenes; luminescence; FLUORESCENCE; siloxanes; CHROMOPHORES; OPTICAL-PROPERTIES; STATE; SPECTRA; nanostructures; excimers
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200901307

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. What excitement! 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 and modeled theoretically. In contrast to the classical systems, an excimer is formed only when two branches of the same cyclotetrasiloxane scaffold are close enough together when the excitation takes place (see scheme).