- Bolag, A.; Sakai, N.; Matile, S. “Dipolar Photosystems: Engineering Push-Pull Components into Double- and Triple-Channel Surface Architectures” Chem. Eur. J. 2016, 22, 9006-9014
Push–pull aromatics are not popular as optoelectronic materials because their supramolecular organization is difficult to control. However, recent progress with synthetic methods has suggested that the directional integration of push–pull components into multicomponent photosystems should become possible. In this study, we report the design, synthesis, and evaluation of double- or triple-channel architectures that contain π stacks with push–pull components in parallel or mixed orientation. Moreover, the parallel push–pull stacks were uniformly oriented with regard to co-axial stacks, either with inward or outward oriented push–pull dipoles. Hole-transporting (p) aminoperylenemonoimides (APIs) and aminonaphthalimides (ANIs) are explored for ordered push–pull stacks. For the co-axial electron-transporting (n) stacks, naphthalenediimides (NDIs) are used. In double-channel photosystems, mixed push–pull stacks are overall less active than parallel push–pull stacks. The orientation of the parallel push–pull stacks with regard to the co-axial NDI stacks has little influence on activity. In triple-channel photosystems, outward-directed dipoles in bridging stacks between peripheral p and central n channels show higher activity than inward-directed dipolar stacks. Higher activities in response to direct irradiation of outward-directed parallel stacks reveal the occurrence of quite remarkable optical gating.
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