Luminescent Detection of Photomagnetic Effect in a Near-Infrared Emissive Neodymium(III)-Octacyanidotungstate(IV) Framework

Abstract

Photomagnetic materials form a class of magnetic systems, in which light irradiation changes their magnetization. Photomagnetic behavior is often observed in spin transition materials, including spin-crossover complexes, and can lead to long-range magnetic ordering. Photo-induced magnetization can affect different physical properties, including second harmonic generation. Still, despite a growing number of luminescent spin-crossover systems, the simultaneous switching of both magnetism and luminescence was not yet explored. In this regard, we present systematic studies for a novel coordination polymer composed of anionic Nd^III-[W^IV(CN)₈]^4- layers, crystallizing with chiral organic cations embedded in the interlayer space. Not only we observe and rationalize theoretically near-infrared emission of Nd^III centers sensitized by [W^IV(CN)₈]^4- units, but we also found a plausible pathway to track the photomagnetic effect throughout the analysis of the Nd³⁺ excitation spectra and their temperature dependence. The observed thermally reversible effects in luminescence were correlated with the results of photomagnetic studies, providing an attractive pathway to monitor the light-induced magnetization changes through a photoluminescent read-out.

Keywords: Cyanides; Luminescence; Molecule‐based magnets; Near‐infrared emission; Photo‐switching.