- Maity, S.; Bhosale, R.; Banerji, N.; Vauthey, E.; Sakai, N.; Matile, S. “Optoelectronically Mismatched Oligophenylethynyl-Naphthalenediimide SHJ Architectures” Org. Biomol. Chem. 2010, 8, 1052-1057
The objective of this study was to evaluate the possibility of photodinduced stack/rod electron transfer in surface “zipper” architectures composed of stacks of blue (B) naphthalenediimides (NDIs) along strings of oligophenylethynyl (OPE) rods. Synthesis and characterization of anionic and cationic multichromophoric OPE-B systems are reported. Absorption spectra suggest that in OPE-B systems, planarity and thus absorption and conductivity of the OPE can possibly be modulated by intramolecular stacking of the surrounding NDIs, although interfering contributions from aggregation remain to be differentiated. Among surface architectures constructed with OPE-B and POP-B systems by zipper and layer-by-layer (LBL) assembly, photocurrents generated by OPE-B zippers exhibit best critical thickness and fill factors. These findings confirm existence and functional relevance of topologically matching zipper architectures. In OPE-B zippers, OPEs generate much more photocurrent than the blue NDIs. Ultrafast electron transfer from OPEs to NDIs accounts for these photocurrents, providing wavelength-controlled access to rod-stack charge separation and thus to formal supramolecular n/p-heterojunctions (SHJs). NDI excitation is not followed by the complementary hole transfer to the OPE rod. Scaffolds with higher HOMO will be needed to integrate blue NDIs into SHJ photosystems.