Photoluminescent Cu(I) Assemblies with High‐Temperature Solid‐State Transitions as a New Class of Thermic History Tracers

The preparation of a new series of luminescent one dimensional coordination polymers based on the association of a photoactive tetrametallic metallacycle Cu(I) precursor with pyridyl‐caped ditopic linkers is reported. In spite of related molecular architectures, these coordination polymers present upon Ultraviolet visible light photoexcitation markedly contrasted solid‐state luminescence behaviors including eye‐perceived colors of the emitted light spanning all over the visible spectrum. Solid‐state temperature‐dependent photophysical measurements and Time‐dependent density‐functional theory calculations have been conducted to identify the relaxation pathways lying in these assemblies. Very importantly, thermal stability studies at high temperature for all these derivatives reveal an irreversible post‐synthetic solid‐state transition that impacts dramatically the photophysical properties of these newly obtained phases, highlighting an innovative family of stimuli‐sensitive materials that can witness the exceeding of critical temperatures in their environment.