Phenothiazinyl‐Substituted Cyanines: Model Compounds for Molecular Switches

Almost orthogonal to the vinamidinium system, the phenothiazine unit in salts of type 1 is electronically “disconnected” from the conjugated system. By flash excitation of 1 an electron is transferred from the phenothiazine to the vinamidinium moiety, which gives rise to a relatively long-lived T1 state, most likely corresponding to the radical dication in 2. Compounds of type 1 are thus models for a molecular switch. X− = BF, ClO.