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Updated: May 18, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
The importance of the rotor in hydrazone-based molecular switches
Xin Su1, Timo Lessing, Ivan Aprahamian
1Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States.
Abstract:
The pH-activated E/Z isomerization of a series of hydrazone-based systems having different functional groups as part of the rotor (R = COMe, CN, Me, H), was studied. The switching efficiency of these systems was compared to that of a hydrazone-based molecular switch (R = COOEt) whose E/Z isomerization is fully reversible. It was found that the nature of the R group is critical for efficient switching to occur; the R group should be a moderate H-bond acceptor in order to (i) provide enough driving force for the rotor to move upon protonation, and (ii) stabilize the obtained Z configuration, to achieve full conversion.
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