Cyanobuta-1,3-dienes as Novel Electron Acceptors for Photoactive Multicomponent Systems

The synthesis, electrochemical, and photophysical properties of five multicomponent systems featuring a ZnII porphyrin (ZnP) linked to one or two anilino donor‐substituted pentacyano‐ (PCBD) or tetracyanobuta‐1,3‐dienes (TCBD), with and without an interchromophoric bridging spacer (S), are reported: ZnP‐S‐PCBD (1), ZnP‐S‐TCBD (2), ZnP‐TCBD (3), ZnP‐(S‐PCBD)2 (4), and ZnP‐(S‐TCBD)2 (5). By means of steady‐state and time‐resolved absorption and luminescence spectroscopy (RT and 77 K), photoinduced intramolecular energy and electron transfer processes are evidenced, upon excitation of the porphyrin unit. In systems equipped with the strongest acceptor PCBD and the spacer (1, 4), no evidence of electron transfer is found in toluene, suggesting ZnP→PCBD energy transfer, followed by ultrafast (