Triboluminescence of Lanthanide Coordination Polymers with Face‐to‐Face Arranged Substituents

Luminescence upon the grinding of solid materials (triboluminescence, TL) has long been a puzzling phenomenon in natural science and has also attracted attention because of its broad application in optics. It has been generally considered that the TL spectra exhibit similar profiles as those of photoluminescence (PL), although they occur from distinct stimuli. Herein, we describe for the first time a large spectral difference between these two physical phenomena using lanthanideIII coordination polymers with efficient TL and PL properties. They are composed of emission centers (TbIII and EuIII ions), antenna (hexafluoroacetylacetonate=hfa), and bridging ligands (2,5‐bis(diphenylphosphoryl)furan=dpf). The emission color upon grinding (yellow TL) is clearly different from that upon UV irradiation (reddish‐orange PL) in TbIII/EuIII‐mixed coordination polymers [Tb,Eu(hfa)3(dpf)]n (Tb/Eu=1). The results directly indicate the discrete excitation processes of PL and TL. Polymers that spark in the dark: Lanthanide coordination polymers with strong tribo‐ and photoluminescence properties were successfully fabricated by introducing a face‐to‐face arrangement of substituents between single polymer chains. These compounds exhibited large spectral differences upon grinding and UV irradiation.