Spectroscopic Investigation of Anhydrous Solutions of Europium Perchlorate and Europium Nitrate in N, N‐Dimethylformamide

Abstract

AbstractAnhydrous solutions of Eu(ClO4)3 and Eu (NO3)3 0.05m in N, N‐dimethyl formamide (DMF) are investigated by means of conductometric measurements, vibrational spectroscopy, electronic absorption and emission spectra, and fluorescence lifetime determinations. Eu (ClO4)3 is completely dissociated and no inner‐sphere interaction takes place between ClO4 and Eu3+ ions. The solvated species Eu (DMF) has a C2v‐symmetry and x is probably equal to 8.A more complicated situation occurs for Eu (NO3)3, the solutions of which contain at least three different solvates; the predominant species is [Eu (NO3)2 (DMF)x−4]+ (≈80% of the total Eu‐concentration) and it is more stable than the mononitrato complex [Eu (NO3) (DMF) X−2]2+; the neutral complex Eu (NO3)3 (DMF) x−6 is also present, as can be inferred from a high‐resolution analysis of the 5D0→7F0 emission band. The absence of emission from the excited 5D1‐level can be rationalized in terms of an efficient non‐radiative deexcitation path through a vibrational mode of the DMF‐molecules bonded to the central metal ion.