Seven- and eight-coordinate lanthanide(III) amidophosphate complexes: synthesis, characterization and photoluminescence

Abstract

Diphenyl N-dimethylamidophosphate, O=P(OPh)2(NMe2), was introduced in the coordination sphere of trivalent lanthanide ions in combination with ß-diketonates, to obtain seven- and eight-coordinated complexes having general formula [Ln(ß-dike)3{O=P(OPh)2(NMe2)}n] (Ln = Eu, ß-dike = dibenzoylmethanate, n = 1; Ln = Eu, ß-dike = tenoyltrifluoroacetonate, n = 2; Ln = Tb, ß-dike = acetylacetonate, n = 2). The compounds were characterized spectroscopically and, in the case of the dibenzoylmethanate derivative, by means of single-crystal X-ray diffraction. The Eu(III) complexes exhibited bright red emission associated to the 5D0→7FJ transitions of the metal centre, with noticeable antenna-effect from the coordinated ligands and lifetimes strongly dependent upon the coordination number. The Tb(III) derivative showed intense green photoluminescence, related to the 5D4→7FJ transitions of the metal ion