Praseodymium β-diketonates and luminescence properties of their solutions

Abstract

The luminescence intensity of Pr(III) in a series of complexes with alkyl and thienyl fluoroacetylacetone derivatives has been shown to increase not only with an increase in the length of the fluoroalkyl radical but also with the introduction of an oxygen heteroatom into this radical. The luminescence intensity of Pr(III) increases by about two orders of magnitude when a donor ligand (an organic solvent) is introduced into the complex. In some cases, the triplet level of β-diketone become higher due to interligand energy transfer and the Pr(III) luminescence occurs from two emitting levels 1D2 (the 1D2 → 3H4 transition, λlum = 605 nm) and 3P0 (the 3P0 → 3H6 transition, λ = 612 nm). Heteroleptic Pr(III) β-diketonates have short lifetimes (τ); for example, the lifetime of the Pr(III) complex with thenoyltrifluoroacetone and diantipyrylmethane is shorter than 1 µs.