Manipulating Photoisomerization Rate of Triphenylethylene Derivative Through Metal Coordination for Irradiation Time-Dependent Information Encryption

Achieving on-demand control of responsive behaviors of photochromic molecules is important for advanced photonic applications, but it remains a challenge. In this work, a triphenylethylene-based molecule, 5-(2,2-bis(4-fluorophenyl)vinyl)-5 ''-methyl-2,2 ''-bipyridine (1), which can undergo open-to-closed isomerization under 365 nm irradiation, is designed and synthesized. Importantly, on-demand acceleration or deceleration of photoisomerization rate over a wide range (k(UV) = 0.00584-0.06299 s(-1)) is achieved by coordination of 1 with different metal salts. Furthermore, more precise manipulation of the photoisomerization rate is achieved by changing the counterions of the 1-based metal complex. Eventually, taking advantage of distinctly different photoisomerization rates of 1 and its corresponding metal complexes, high-level irradiation time-dependent information encryption and anticounterfeiting applications have been demonstrated.