The conjugate base of methyl 3-oxobutanoate as an antenna ligand in visible-emitting photoluminescent lanthanide complexes

Coordination compounds with the formulae [Y(MAA)(3)](x) (1(Y)), [Ln(MAA)(3)](x) (1(Ln)), [Y(MAA)(3)(phen)] (2(Y)) and [Ln(MAA) (3)(phen)] (2(Ln)) (Ln = Sm, Eu, Tb, Dy, Yb; MAA = conjugate base of methyl 3-oxo-butanoate; phen = 1,10-phenantroline) were synthesized and characterized, and X-ray diffraction data were collected for [Tb(MAA)(3)(phen)] (2(Tb)) and [Yb(MAA)(3)(phen)] (2(Yb)). Most of the lanthanide derivatives showed appreciable luminescence in the solid state upon excitation with near-UV light. Strong emissions were observed in particular for complexes of lanthanide ions with high-energy resonance levels. Visibleemitting [Ln(MAA)(3)(phen)] compounds were successfully used as dopants for the preparation of luminescent poly(methylmethacrylate) samples. Similar derivatives of the conjugate base of dimethyl malonate (DMM), with formulae [Y(DMM) (3)(phen)] (3(Y)) and [Ln(DMM) (3)(phen)] (3(Ln)) (Ln = Eu, Tb, Dy), were also synthesized and their photoluminescence behaviour was compared to that of the analogous methyl 3-oxo-butanoato-complexes.