Photochemical and Electrochemical Triggered Bis(hydrazone) Switch

Herein, we report the synthesis of a double hydrazone capable of undergoing photochemical E/Z isomerization through the imine double bonds. The bis(hydrazone) 1‐E,E can be considered as a “two‐arm” system in which the controlled movement of each arm is obtained by photo‐modulation, making possible the appearance of two isolable metastable isomeric states 1‐E,Z and 1‐Z,Z. Such states are characterized by very specific structural, optical, and electrochemical properties. The latter allows the reversible return from either 1‐E,Z or 1‐Z,Z to the 1‐E,E state. Our results are of great importance in the further development of molecular machines and photochemically controlled reactions by introducing for the first time double hydrazones as tunable photochemical switches. Translation En este trabajo presentamos la síntesis de una doble hidrazona capaz de experimentar isomerización fotoquímica E/Z a través de los dobles enlaces imina. La bis(hidrazona) 1‐E,E puede ser considerada como un sistema de “dos brazos” en el cual el movimiento controlado de cada brazo es obtenido por foto‐modulación, siendo posible la aparición de dos estados isoméricos metaestables 1‐E,Z y 1‐Z,Z. Los 3 isómeros están caracterizados por sus propiedades estructurales, ópticas y electroquímicas. El estudio de estas últimas, muestra el retorno de manera reversible de los estados 1‐E,Z o 1‐Z,Z al estado 1‐E,E. Nuestros resultados son de gran importancia para el desarrollo de máquinas moleculares y reacciones controladas fotoquímicamente, presentando por primera vez hidrazonas dobles como interruptores fotoquímicos manipulables. Switching sides: The synthesis of a double hydrazone capable of undergoing photochemical E/Z isomerization through the imine double bonds is reported. The bis(hydrazone) 1‐E,E can be considered as a “two‐arm” system in which the controlled movement of each arm is obtained by photo‐modulation, making possible the appearance of two isolable metastable isomeric states 1‐E,Z and 1‐Z,Z (see scheme).