Year: 2026
Type: preprint
Abstract: Photoswitches based on E/Z isomerism around a C=N bond have found wide-reaching applications in materials science and biology. Herein, we report a new class of hydrazone photoswitch based on aminated nitrogen heterocycles, the N-aminated N-heterocyclic hydrazones (NaNs). These photoswitches can be synthesised in a single step, achieve near quantitative photoswitching, offer visible light (470 nm) response, have thermal half-lives of up to 958 hours at room temperature and quantum yields of up to 70%. We have investigated the impact of different structural features on switch properties by studying a library of 30 derivatives with varied N-amino N-heterocyclic components and varied aldehyde components. These have been extensively studied in the solution and solid state, towards understanding structure-activity relationships for rational NaN photoswitch design. The stability of the metastable state facilitated the growth of the Z-isomer crystals for an anthracene derived NaN, and we observed both E/Z isomerisation and dimerisation of the anthracene, depending on irradiation duration. Furthermore, we demonstrate a member of the library undergoes E→Z photoisomerisation in the solid state, displaying single crystal to single crystal switching. We anticipate that the simple synthesis of these compounds, combined with their tuneable properties, will ensure that they find widespread application across numerous fields.
Source: ChemRxiv
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220736169