Stoichiometry-controlled structural and functional variation in two photochromic iodoargentates with a fast and wide range response

Abstract

By using 1-methyl-4-(carbomethoxy)pyridinium (MCMP⁺) as counterions, two iodoargentate hybrids, 1D [MCMP][AgI₂] (1) and 3D [MCMP][Ag₃I₄] (2) have been synthesized and they exhibit rare electron transfer photochromism with a fast response rate, a wide response range and a long-lived charge-separated state in iodometallate systems. Noteworthily, the marked differences in the structure and photochromic performance of 1 and 2 are largely ascribed to the different aggregating behavior of electron-deficient MCMP⁺ counterions (C–H⋯O hydrogen bonded trimer in 1 and π–π/C–H⋯π chain in 2).