Synthesis, Photophysical Studies, and Self-Assembled Monolayers
A series of mono- (MPTTF) and bis(pyrrolo) tetrathiafulvalene (BPTTF) derivatives tethered to one or two C-60 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 C-60. Electronic communication between the MPTTF/BPTTF units and the C-60 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 C-60 moieties. In addition, femtosecond and nanosecond transient absorption spectroscopy revealed, rather surprisingly, that no charge transfer from the MPTTF/BPTTF units to the C-60 moieties takes place on excitation of the fullerene moiety. Finally, it was shown that the MPTTF-C-60 and C-60-BPTTF-C-60 dyad and triad molecules formed self-assembled monolayers on a Au(111) surface by anchoring to C-60.
Chemistry: a European Journal, 2014, Vol 20, Issue 32, p. 9918-9929