Construction of Dimension-Dependent Naphthalenediimide-Based MOF Materials with Free Hydroxyl Active Sites: Stimulation Responses of Ionochromism, Electrochromism, and Visual Artificial Film Labeled on Cations

Smart metal–organic framework (MOF) chromic materials that respond to chemical or electrical stimuli are highly desirable for daily life and optoelectronic applications. Three novel MOFs: [Mn(H 2 NDISA)(DMF) 2 ] ( 1 ), [Zn(H 2 NDISA)(DMF) 2 ] ( 2 ), and [Cd(H 2 NDISA)(DMF) 2 ] ( 3 ) are first synthesized and characterized, based on a H 4 NDISA ligand (H 4 NDISA ( N, N ′-bis(3-carboxy-4-hydroxyphenyl)-1,4,5,8-naphthalenetetradicarboximide)) with free hydroxyl active sites. Structural analysis reveals that complexes 1 – 3 display a 3D supramolecular network, a 2D layered structure, and a 1D chain structure, respectively, because of different intermolecular interactions, affording them with dimension-dependent multistimulus-responsive chromism behaviors. Alkali metal ion-induced chromism is related to topological structures of the complexes, as well as the type and concentration of ions. Regarding alkaline earth metal ions, complexes 1 – 3 change from yellow to red in Be 2+ . As for fourth-period transition-metal ions, complexes 1 – 3 display deep red and brown colors in Fe 3+ and Cu 2+, respectively, rendering these complexes as selective and sensitive visual ion detectors when fabricated as portable polyvinylidene difluoride-polyethylene glycol@ 1 – 3 films (PVDF–PEG@ 1 – 3 films). Furthermore, complexes 1 – 3 exhibit electrochromic switching properties, and chromic voltages are related to dimension of MOFs, which may provide proof-of-concept for low-energy electrochromic applications. This study might enrich the potential application of naphthalenediimide-based MOF materials in cation detection and optoelectronic devices.