Silver ion integrated organically functionalized Anderson-type polyoxometalate exhibiting photochromism and sensitive ultraviolet detection

Abstract

Photochromic materials are considered ideal candidates for precise photodetection; however, their practical applications are often limited by issues such as insufficient stability and non-linear chromic behavior. In this study, a novel silver ion integrated organically functionalized Anderson-type polyoxometalate compound, featuring a three-dimensional (3D) framework of [Ag₈H{MnMo₆O₁₈[(OCH₂)₃CNHCOHNC₄H₉]₂}₃(CH₃CN)₁₅·18CH₃CN]_n (1), was synthesized. The incorporation of Ag⁺ confers marked photoresponsive activity on 1. Under ultraviolet (UV) light irradiation, Ag⁺ ions are rapidly reduced to Ag⁰ and undergo aggregation. This reduction process induces a pronounced colorimetric change, characterized by a transition from light orange to black. The absorbance of 1 at 600 nm exhibits a favorable linear correlation with UV light intensity, enabling sensitive detection of ultraviolet light. The unique 3D framework architecture of 1 enhances structural stability while effectively stabilizing photoreduction products, thereby ensuring long-term signal response stability. This work not only provides a novel model compound for designing functionalized polyoxometalate-based photochromic materials but also establishes a pioneering technical approach for detecting ultraviolet radiation.