Polyoxometalate/s-triazine hybrid heterostructures with ultrafast photochromic properties

Abstract

As an emerging class of hybrid complexes, donor–acceptor (D–A) hybrid heterostructures, which combine the advantages of both organic and inorganic photoactive components, provide excellent platforms for the fabrication of photochromic materials with enhanced photo-responsive performances. Herein, four novel hybrid heterostructures, namely H₃TPT·(PW₁₂O₄₀)·2NMP (1), (H_1.5TPT)₂·(PW₁₂O₄₀) (2), (H₃TPT)₂·(SiW₁₂O₄₀)·2Cl·2MeCN (3), and H₃TPT·(HPMo₁₂O₄₀)·Cl·3NMP (4) (TPT is tri(4-pyridyl)-s-triazine, NMP is N-methylpyrrolidone), have been synthesized and characterized. Benefitting from the strong interactions (anion–π interactions) and matching electron energy levels between the donors and acceptors, some of them exhibited ultrafast photochromic behaviour even up to 1 second. Furthermore, based on experimental and theoretical calculations, the plausible PIET process and structure–activity relationship have been discussed in detail.