Ultrafast visible-light photochromic properties of naphthalenediimide-based coordination polymers for the visual detection/filtration of blue light

Two novel naphthalenediimide-based (NDI-based) coordination polymers (CPs), namely [Cd(3-PMNDI)(HNDC) 2 (DMF)] ( 1 ) and [Cd(4-PMNDI)(NDC)]·DMF ( 2 ) (H 2 NDC = 1,4-naphthalenedicarboxylic acid, 3-/4-PMNDI = N , N ′-bis(3-/4-pyridylmethyl)-1,4,5,8-naphthalenediimide, DMF = N , N ′-dimethylformamide), have been designed and synthesized here from positional isomeric electron-deficient PMNDI (electron acceptors, EAs) and electron-rich H 2 NDC (electron donors, EDs) in the presence of cadmium ions. The usage of the positional isomeric PMNDI ligands leads to the generation of a one-dimensional (1D) chain in 1 and a two-fold interpenetrated three-dimensional (3D) framework in 2 . Interestingly, both compounds exhibit outstanding ultrafast visible-light photochromic properties based on photoinduced intermolecular electron transfer (PIET). The higher sensitivity of 1 and 2 to visible light relative to UV light could be ascribed to the typical arrangements of EDs/EAs in the interfacial contacts (ED-EA-ED in 1 vs. ED-EA-EA-ED in 2 ). Furthermore, the difference in the number and strength of weak interactions (lone pair-π and π-π interactions) between EDs and EAs might be responsible for the discriminative photoresponsive rates (5 s for 1 vs. 10 s for 2 ). Meanwhile, the different coloration states might be contributed by the distinct concentrations of the [PMNDI]&z.rad; − anionic radicals and their delicately different matrices or surrounding environments. Notably, both 1 and 2 are highly photosensitive to blue-light wavelengths, which can be viewed as typical of photochromic materials for the detection and filtration of blue light. Two naphthalenediimide-based coordination polymers exhibit ultrafast visible-light photochromic properties for blue light detection/filtration.