Zinc(II)–Organic Framework Films with Thermochromic and Solvatochromic Applications

Multiple‐stimuli‐responsive photoluminescence films based on a Zn II –organic framework, {[Zn 2 (Htpim)(3,4‐pydc) 2 ] ⋅ 4 DMF ⋅ 4 H 2 O} n ( 1 , Htpim=2,4,5‐tri(4‐pyridyl)imidazole, 3,4‐H 2 pydc=3,4‐pyridinedicarboxylic acid), were fabricated. This compound consisted of a 2D corrugated layer, {Zn(3,4‐pydc)} n , which was further pillared using a Y‐shaped pillar N‐donor ligand (Htpim) to form a 3D‐pillared‐layer framework with 1D open channels. The rectangular channels in the as‐synthesized compound are fully occupied by guest DMF and H 2 O molecules. The framework exhibits instant and reversible thermochromic properties corresponding to the removal of different H 2 O and DMF guest molecules as temperature increases. The pale‐yellow crystal undergoes significant redshifting to a greenish emission centered at 530 nm. Compound  1 also showed remarkable solvatochromic effects in the presence of various organic solvents without affecting its structural integrity. In addition, polycrystalline MOF films were grown on an α‐Al 2 O 3 support for switchable and fast‐response thermochromic and solvatochromic sensors.