Dithiafulvenyl-Extended N-Heterotriangulenes and Their Interaction with C₆₀ : Cooperative Fluorescence

We describe the synthesis as well as the electronic and photophysical characterization of novel N-heterotriangulene derivatives decorated with methoxycarbonyl- and methyl-sulfanyl-substituted dithiafulvenyl moieties. The association of these electron-rich compounds with fullerene C₆₀ as electron acceptor was investigated by means of photophysical, voltammetric, and mass spectrometric methods and rationalized by DFT calculations. Importantly, light-induced interactions between the dithiafulvene-substituted N-heterotriangulene bearing methoxycarbonyl substituents with C₆₀ leads to cooperative fluorescence. Quantitative Job plot analyses by means of fluorescence spectroscopy and voltammetry confirm a 1:1 association with binding constants in the order of 10⁴  m^-1 . Supportive results for the supramolecular assembly of both N-heterotriangulenes with C₆₀ were obtained by ESI mass spectrometric investigations in the gas phase.