Photochromism and photocatalysis of organic–inorganic hybrid iodoargentates modulated by argentophilic interactions

Abstract

Four organic–inorganic hybrid iodoargentates, [MDMBI]₂[Ag₂I₄] (1), [HDMBI]₄[Ag₄I₈] (2), [MBI][Ag₂I₃] (3), and [MDMBI][Ag₂I₃] (4) (MBI⁺ = N,N-dimethylbenzimidazolium, MDMBI⁺ = N,N-dimethyl-5,6-dimethylbenzimidazolium, HDMBI⁺ = N-proton-5,6-dimethylbenzimidazolium), have been synthesized with combination of benzimidazolium cations and iodoargentate anions. 1 presents a typical 1-D [Ag₂I₄]²⁻ inorganic chain, 2 exhibits a novel 2-D [Ag₄I₈]⁴⁺ inorganic layer, and both 3 and 4 possess a 1-D [Ag₂I₃]⁻ inorganic chain with different bonding modes. Importantly, the absence of Ag⋯Ag contacts in 1 and 2 leads to an optically inert response, and the distinct number and strength of argentophilic interactions in 3 and 4 give rise to completely different photochromic behaviors based on the photolysis of iodoargentate frameworks and photocatalytic degradation of rhodamine B (RhB) molecules, exhibiting a delicate modulating effect of argentophilic interactions on the electronic behaviors including the photochromic and photocatalytic properties.