Multiple stimulus responsive of a novel naphthalenediimide-based 2D alkaline-earth metal MOF material: Hydrochromism, amine-/acid-induced chromism and ionochromism as well as visual artificial film application.

The NDISA-based 2D MOF constructed from alkali-earth metal ion have been firstly synthesized. Ca-NDISA showed multiple stimulus responsive chromic behaviors including hydrochromism, amine-/acid-induced chromism, and ionochromism, as well as had multifunctional applications. In addition, the PMMA@ Ca-NDISA film was applied as humidity sensor and acids/amines detector. [Display omitted] • The NDISA-based 2D MOF was firstly synthesized and its structural characterized. • Ca-NDISA possesses hydrochromism performance and multifunctional applications. • Ca-NDISA can recognize acids and amines through amine-/acid-induced chromism. • Ca-NDISA can naked-eye discriminated and detected I− through ionochromism. • PMMA@ Ca-NDISA film was applied as humidity sensor and acids/amines detector. Metal–organic frameworks (MOFs) with naphthalene-1,4,5,8-tetracarboxylic dianhydride (H 4 NDISA) chromophoric unit provide an intriguing platform for the design of multiple stimulus responsive materials. Herein, the first NDISA-based 2D MOF [Ca(H 2 NDISA)(DMF) 3 ]∙H 2 O (Ca-NDISA) constructed from alkaline-earth metal ion was successfully synthesized. The structural analysis shown that a binuclear secondary building unit (SBU) [Ca 2 (COO) 2 (DMF) 6 ] is extended to generate a 2D planar network structure with abundant open-activity sites, endowing Ca-NDISA with multiple stimulus responsive chromic behaviors. Ca-NDISA could undergo a color change from yellow to red in hydrochromism, rendering it with the applications in detecting the water content of organic solvents, as a humidity sensor when fabricating a PMMA@ Ca-NDISA film, and a potential hydrochromic imaging material. In amine-/acid-induced chromism, Ca-NDISA respectively changed its color to red and brown when exposed to strong acid and some small size ammonia/organic amines vapors environment, which makes the PMMA@ Ca-NDISA film as a visual and portable recognition detector for acids and amines. In ionochromism, Ca-NDISA is suitable for the naked-eye discrimination and detection of I− with obvious color change to black brown. Our work not only provide a facile way to obtain NDISA-based 2D MOF with multi-stimulus responsive chromic properties, but also present some convenient chromism devices, which will enrich the family of multifunctional chromic materials for practical applications. [ABSTRACT FROM AUTHOR]