A fluorescent, photochromic and thermochromic trifunctional material based on a layered metal–viologen complex

Abstract

The azide anion as an energy acceptor and an electron donor has been introduced into a metal-viologen compound to form a 2D layered viologen-based trifunctional material, which exhibits the rare discolored function of reversible photochromism and thermochromism. Interestingly, its fluorescence can be switched by visible light irradiation and heating in air.

Cu(ii)/Ni(ii)–organic frameworks constructed from the homometallic clusters by 5-(2-carboxyphenoxy)isophthalic acid and N-ligand: synthesis, structures and visible light-driven photocatalytic properties

“…6,11,12 For example, Zn(II), Cd(II), Cu(II), Ni(II), and Co(II), with different electron congurations and coordination numbers, may form compounds in various architectures, which can be applied to catalysis and luminescence. [13][14][15][16][17][18] Among them, Cu (II) and Ni(II) complexes have shown to be effective chemical photocatalysts under visible light irradiation. [19][20][21][22] The development of MOFs has provided more opportunities for new photocatalysts, because of their diverse structures containing variable valence electrons and empty orbits of the metal center, high thermal and chemical stability.…”

A Barrel‐Shaped Metal–Organic Blue‐Box Analogue with Photo‐/Redox‐Switchable Behavior

“…The more mild nature of UV irradiation, compared with chemical reduction or heat, allows the retention of crystallinity,e ven if less radicals are likely to be generated. [54,55] The structures of the photochemically reduced nanocapsules, wherein at least part of the V 2 + units have been converted into the one-electron-reduced V + C have been retained, yet examination of some key bond lengths suggestatrend towards the presence of viologen-based radicals (Figure 3). To further highlight this, we have synthesized the diamagneticy ttrium analogue (2), the solid-states tructure of which was identical to that of 1 (Table S1 in the Supporting Information).…”

The photochromic behaviour of two viologen salts modulated by the distances between the halide anions and the cationic N atoms of viologen

“…Photochromic materials exhibit potential applications in many fields, including electrochemistry, photochemistry, supramolecular chemistry, synthetic chemistry and biochemistry (Wu et al, 2015;Ebbesen et al, 1982;Michaelis & Hill, 1933), which can be used in the design of flow batteries, solar-energy conversion, photocatalytic hydrogen evolution, displays, anticounterfeiting guarantees, smart windows, information storage and optical switches (Janoschka et al, 2015;Wang et al, 2014;Kotani et al, 2006;Wu et al, 2011;Rogez et al, 2010;Yang et al, 2016;Gong et al, 2017Gong et al, , 2018Gong & Lu, 2013;Wan et al, 2015, Li, Xu et al, 2018. Most of the known photochromic systems may undergo cis-trans configurational rearrangements, structural changes from open-loop to closedloop or electron transfer (Zhu et al, 2011;Chen et al, 2012).…”