Neodymium(iii)-containing solids are the most popular luminescent materials for application in laser systems. [1] Inorganic Nd III compounds such as oxides, fluorides, phosphates, and their mixed matrices were investigated for the capability of high power laser radiation by controlling the Nd III density in matrices. The construction of strongly luminescent Nd III materials in organic media would be desirable for developing applications in novel organic Nd III devices, such as organic liquid lasers, optical-fiber polymers, organic electroluminescent devices, and near-IR immunoassays. [2] However, the energy gap theory shows that the presence of CΓH or OΓH bonds in the vicinity of Nd III leads to effective radiationless transitions by vibrational excitation of CΓH or OΓH bonds, and this results in negligible emission quantum yields. [3] Suppression of such vibrational excitation in the Nd III system requires deuteration of CΓH and OΓH bonds or replacement of CΓH bonds with CΓF bonds in ligating molecules, and the use of deuterated solvents with low vibrational frequencies. By using these strategies, various researchers recently observed effective emission in certain organic/Nd III systems. [4] However, an emission quantum yield on the order of 10 Γ5 was never observed in solvents that contain H atoms. Here we report on the luminescence of novel Nd III complexes and the first observation of enhanced luminescence of Nd III in a solvent of high vibrational frequency, namely, undeuterated acetone, by using bis(perfluoroalkylsulfonyl)aminates as bulky ligands with low vibrational frequencies.
Bis(perfluorooctylsulfonyl)amine (posH) was synthesized by treating the corresponding perfluorooctylsulfonylamine with perfluorooctylsulfonyl fluoride in the presence of triethylamine (TEA) as base in THF, followed by acidification with 10 % aqueous H 2 SO 4 . [Nd(pos) 3 ] was prepared by treating posH with neodymium oxide in water. For comparison, we prepared [Nd(pbs) 3 ] (pbs bis-perfluorobutylsulfo-