Halogen-dependent photoinduced electron transfer and chromism of three protonated nicotinohydrazide halozincates

Abstract

Three isostructural halozincates, [HNH][ZnX₄]·H₂O (HNH²⁺ = protonated nicotinohydrazide, X = I (1), Br (2), Cl (3)), have been synthesized and exhibit halogen-dependent photoinduced electron transfer and chromic properties. Due to the different electron-donating nature of halogen atoms, only iodozincate hybrid 1 can easily undergo photoinduced electron transfer and eye-detectable photochromic behavior, revealing a unique matching rule between a moderate electron acceptor and halozincates.