Fresh Look on the Nature of Dual-Band Emission of Octahedral Copper-Iodide Clusters—Promising Ratiometric Luminescent Thermometers

Abstract

For the first time, the 3(X + M)LCT origin of both the lowest excited triplet states of dual-emissive tetranuclear copper(I)-iodide complexes with the octahedral Cu4I4 core has been revealed using quantum chemical computations in contrast to the conventional assignment of the lowest-energy emission to the 3CC state. The unusual thermochromic behavior shown for dual emission from these states of Cu4I4 clusters stabilized by P,N-ligands allows optical ratiometric thermal sensing in a broad temperature range.