No abstract

Novel yttrium, europium and terbium coordination compounds having formulae [AsPh4][Ln(BrMA)4] (6LN), Ln(BrMA)3(bipyO2) (7Ln), Ln(NMA)3(phen) (8Ln) and Ln(NMA)3(terpy) (9Ln) (Ln = Y, Eu, Tb; BrMA = conjugate base of bromomalonaldehyde; bipyO2 = 2,2'-bipyridine-N,N'-dioxide; phen = 1,10-phenantroline; terpy = 2,2':6',2''-terpyridine) were synthesized and characterized by using spectroscopic and electrochemical techniques. Uncharged europium and, to a lesser extent, terbium complexes showed appreciable luminescence in the solid state upon excitation with UV light. Polymeric materials and ionic liquids containing BrMA and lanthanides were prepared and photoluminescence measurements were carried out. From an electrochemical point of view, europium(III) BrMA-complexes showed a quasi-reversible one-electron reduction process. The one electron transfer reaction Eu(III) to Eu(II) allowed the photoluminescence tuning of 8Eu deposited on the surface of a glassy carbon electrode.

Coordination compounds having formulae [AsPh4][Ln(NMA)4] (1(Ln)), Ln(NMA)3(tppo)2 (2(Ln)), Ln(NMA)3(bipyO2) (3(Ln)), Ln(NMA)3(phen) (4(Ln)) and Ln(NMA)3(terpy) (5(Ln)) (Ln = Y and some lanthanides; NMA = conjugate base of nitromalonaldehyde; tppo = triphenylphosphine oxide; bipyO2 = 2,2'-bipyridine-N,N'-dioxide; phen = 1,10-phenanthroline; terpy = 2,2':6',2''-terpyridine) were synthesized and characterized and X-ray diffraction data were collected for [AsPh4][Y(NMA)4] (1(Y)). The neutral europium derivatives showed appreciable luminescence in the solid state upon excitation with UV light and photoluminescence measurements were carried out. These compounds were used as dopants for the preparation of luminescent poly(methyl methacrylate). Luminescent polyvinylpyrrolidone samples were obtained by reacting the pure polymer with water solutions containing NMA and trivalent europium ions.