Mono- and Bis(pyrrolo)tetrathiafulvalene Derivatives Tethered to C60: Synthesis, Photophysical Studies, and Self-Assembled Monolayers

• Published in: Chemistry : a European journal 2014-08, Vol.20 (32), p.9918-9929
• Main Authors: Solano, Marta Vico, Della Pia, Eduardo Antonio, Jevric, Martyn, Schubert, Christina, Wang, Xintai, van der Pol, Cornelia, Kadziola, Anders, Nørgaard, Kasper, Guldi, Dirk M., Nielsen, Mogens Brøndsted, Jeppesen, Jan O.
• Format: Article
• Language: English
• Subjects: Chemistry; cycloaddition; donor-acceptor systems; fullerenes; monolayers; Spectrum analysis; tetrathiafulvalenes
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201402623

A series of mono‐ (MPTTF) and bis(pyrrolo)tetrathiafulvalene (BPTTF) derivatives tethered to one or two C60 moieties was synthesized and characterized. The synthetic strategy for these dumbbell‐shaped compounds was based on a 1,3‐dipolar cycloaddition reaction between aldehyde‐functionalized MPTTF/BPTTF derivatives, two different tailor‐made amino acids, and C60. Electronic communication between the MPTTF/BPTTF units and the C60 moieties was studied by a variety of techniques including cyclic voltammetry and absorption spectroscopy. These solution‐based studies indicated no observable electronic communication between the MPTTF/BPTTF units and the C60 moieties. In addition, femtosecond and nanosecond transient absorption spectroscopy revealed, rather surprisingly, that no charge transfer from the MPTTF/BPTTF units to the C60 moieties takes place on excitation of the fullerene moiety. Finally, it was shown that the MPTTF–C60 and C60–BPTTF‐C60 dyad and triad molecules formed self‐assembled monolayers on a Au(111) surface by anchoring to C60. Communication breakdown: Dyads and triads composed of fullerenes and pyrrolotetrathiafulvalenes were prepared by Prato cycloaddition reactions and subjected to detailed electrochemical and photophysical studies, including absorption and fluorescence spectroscopy, as well as femtosecond and nanosecond transient absorption studies, which indicated no observable electronic communication between the tetrathiafulvalene and the C60 moieties (see figure). The dyad and triad molecules form self‐assembled monolayers on gold surfaces.