Synthesis and characterization of the firstly observed two brilliantly triboluminescent lanthanide complexes: 2-hydroxyethylammonium and pyrrolidinium tetrakis(dibenzoylmethide) europate(III). Crystal structure of one brilliantly triboluminescent acentric

Triboluminescent phenomena of 2-hydroxyethylammonium tetrakis (dibenzoylmethide)europate (1) and pyrrolidonium tetrakis(dibenzoylmethide)europate (2) were firstly observed, and the crystal structure of dimethylbenzylammonium tetrakis(dibenzoylmethide)europate (3) was successfully determined after more than 35 years later. Crystal data for 3: orthorhombic, space group Pca21 (No.29), a=25.697(2), b=9.462(3), c=15.023(3) Å, Z=4. The Eu atom exhibits an eight-coordinate tetragonal antiprismatic geometry with an average Eu–O bond distance of 2.42(2) Å. Triboluminescent spectra of 1–3 are basically similar to that of their fluorescent spectra, and the observed triboluminescent emission correlates well with their acentric space group.