Relation between Ligand Design and Transition Energy for the Praseodymium Ion in Crystals

Abstract

Ten substituted benzoate complexes of Pr(3+) of the type [Pr(XC6H4COO)3(H2O)n(DMF)m]p·(DMF)q (X = OCH3, NO2, OH, F, Cl, NH2) have been synthesized, and for eight of these crystallographic data are available. The electronic absorption and emission spectra of the complexes have been recorded and interpreted at temperatures down to 10 K for transitions involving the (3)P0 and (1)D2 J-multiplet terms. Generally, the electron-withdrawing groups X in the benzoate moiety lead to higher (3)P0 energy than electron-donating groups. Empirical relations have been found between the energies of the (3)P0 and (1)D2(1) levels and the Hammett sigma constants for substituents and the unit cell volume per Pr(3+) ion. The latter relationship is indicative of a correlation between the electronic state energy and the ligand dipole polarizability. This has been confirmed by reference to literature data for the LaX3:Pr(3+) systems, so that the ligand dipole polarizability is a key factor in determining the nephelauxetic shifts of 4f(N) ions in crystals.

Embedded lanthanoid ions modulated the periodic luminescence of transition metal dichalcogenide monolayers prepared from an aqueous orecursor

“…[13][14][15] From another view, the optical transition, energy transfer, lifetime, and efficiency of the photoluminescence (PL) of the lanthanoid ions are heavily dependent on the structure of the host lattice. 16,17 In terms of mechanism, the 4f configuration of lanthanoids will be split under the coulombic field, spin-orbital coupling, and crystal field, whose effects decrease in turn. 18 However, whether the law of lanthanoids can be maintained in the surroundings in consideration of all the above factors has not been investigated.…”