| Summary: | Four new Pr(III) mononuclear complexes of formula [Pr(ntfa)<sub>3</sub>(MeOH)<sub>2</sub>] (<b>1</b>), [Pr(ntfa)<sub>3</sub>(bipy)<sub>2</sub>] (<b>2</b>), [Pr(ntfa)<sub>3</sub>(4,4′-Mt<sub>2</sub>bipy)] (<b>3</b>) and [Pr(ntfa)<sub>3</sub>(5,5′-Me<sub>2</sub>bipy)] (<b>4</b>), 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 <b>1, 3</b> and <b>4</b>, and 10 for <b>2</b>. Magnetic measurements of complexes <b>1–4</b> were consistent with a magnetically uncoupled Pr<sup>3+</sup> ion in the <sup>3</sup>H<sub>4</sub> ground state. The solid state luminescence studies showed that the ancillary chelating bipyridyl ligands in the <b>2</b>–<b>4</b> complexes greatly enhance the luminescence emission in the visible and NIR regions through efficient energy transfer from the ligands to the central Pr<sup>3+</sup> ion; behaving as “antenna” ligands.
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