Slow magnetic relaxation and luminescence properties in neodymium(III)-4,4,4-trifluoro-1-(2-naphthyl)butane-1,3-dionato complexes incorporating bipyridyl ligands

Five new eight-coordinated Nd(iii) mononuclear complexes with the formulae [Nd(ntfa)(3)(EtOH)(2)] (1), [Nd(ntfa)(3)(phen)] (2), [Nd(ntfa)(3)(bipy)] (3), [Nd(ntfa)(3)(5,5'-Me(2)bipy)] (4) and [Nd(ntfa)(3)(4,4'-Mt(2)bipy)] (5), where ntfa = 4,4,4-trifluoro-1-(naphthalen-2-yl)butane-1,3-dionate, phen = phenanthroline, bipy = 2,2'-dipyridine, 5,5'-Me(2)bipy = 5,5'-dimethyl-2,2'-dipyridine, and 4,4'-Mt(2)bipy = 4,4'-dimethoxy-2,2'-dipyridine, were synthesized and structurally characterized. Magnetic measurements were carried out on complexes 2-5. Dynamic magnetic studies revealed single-molecule magnet (SMM) behavior for complexes 2, 4 and 5 with anisotropy energy barriers and preexponential factors of U-eff = 18 cm(-1), tau(0) = 2.2 x 10(-7) s; U-eff = 31 cm(-1), tau(0) = 1.0 x 10(-9) s and U-eff = 19 cm(-1), tau(0) = 8.7 x 10(-8) s, respectively. The ancillary chelating bipyridyl ligands in complexes 2-5 greatly enhance the solid state luminescence emission in the visible and NIR regions through efficient energy transfer from the ligands to the central Nd3+ ion. This study highlights the bifunctionality of the Nd(iii) complexes.

Automated summary

In this study, five new eight-coordinated Nd(iii) mononuclear complexes were synthesized and characterized. Three of these complexes exhibit single-molecule magnet behavior with significant anisotropy energy barriers. The use of ancillary chelating bipyridine ligands greatly enhances solid state luminescence emission in the visible and NIR regions.