Phosphinine vs Pyridine in Luminescent CuI Complexes and Application in Lifetime‐Based Molecular Thermometer

Abstract

AbstractLuminescent CuI complexes have attracted significant interest due to their adjustable emission properties, diverse structures, and reasonable cost. In this work, two class of complexes, namely phosphinine and pyridine ligated CuI complexes that differ by only one atom, were synthesized and characterized. Photophysical analysis and theoretical studies reveal an emissive phosphinine‐localized triplet states for CuI phosphinine complexes, and a temperature‐dependent interplay between metal‐to‐ligand charge‐transfer (MLCT) singlet and triplet states for CuI pyridine complexes. In general, the CuI phosphinine complexes exhibit a longer lifetime and greater temperature‐dependent lifetime changes than the pyridine complexes. A molecular thermometer incorporating CuI phosphinine complexes 2 c as indicator was fabricated. This thermometer exhibits a rare linear correlation between temperature and lifetime ranging from 77–297 K with a high sensitivity of −13.5 μs K−1.