Structural characterization, magnetic and luminescent properties of praseodymium(III)-4,4,4-trifluoro-1- (2-naphthyl)butane-1,3-dionato(1-) complexes

Abstract

Four new Pr(III) mononuclear complexes of formula [Pr(ntfa)3(MeOH)2] (1), [Pr(ntfa)3(bipy)2] (2), [Pr(ntfa)3(4,4'-Mt2bipy)] (3) and [Pr(ntfa)3(5,5'-Me2bipy)] (4), where ntfa = 4,4,4- trifuoro-1-(naphthalen-2-yl)butane-1,3-dionato(1-), 5,5'-Me2bipy = 5,5'-dimethyl-2,2'-dipyridine, 4,4'-Mt2bipy = 4,4'-dimethoxy-2,2'-dipyridine, have been synthesized and structurally characterized. The complexes display the coordination numbers 8 for 1, 3 and 4, and 10 for 2. Magnetic measurements of complexes 1-4 were consistent with a magnetically uncoupled Pr3+ ion in the 3H4 ground state. The solid state luminescence studies showed that the ancillary chelating bipyridyl ligands in the 2-4 complexes greatly enhance the luminescence emission in the visible and NIR regions through efficient energy transfer from the ligands to the central Pr3+ ion; behaving as “antenna” ligands.