Spectroscopy and structure of [LnL3bipy] and [LnL3phen] complexes with CAPh type ligand dimethylbenzoylamidophosphate

Coordination compounds with general formulas [LnL(3)bipy] (Ln1) and [LnL(3)phen] (Ln2), where Ln=La-Nd, Sm-Yb, L- -phosphoro-azo beta-diketone analog anion: [C6H5CONPO(OCH3)(2)](-) phen=1,10-phenan-throline, bipy=2,2'-bipyridine, were synthesized and characterized by means of IR, H-1 NMR and high resolution UV-vis absorption and luminescence spectroscopy (emission, excitation spectra and emission decay times) at 300, 77 and 4.2 K. The thermal behavior and stability of Eu-III and Tb-III complexes were studied by thermogravimetric and differential thermal analyses. Single-crystal X-ray diffraction data showed that Pr1, Yb1 and La2, Eu2, Gd2, Yb2 crystalize in the monoclinic and triclinic systems, respectively with eight-coordinated lanthanide ions. The relation between the crystal structure and spectroscopic properties of the complexes are discussed. The Eu-III and Tb-III complexes exhibited a strong metal-centered emission with decay time 1.5-1.8 ms. Intrinsic quantum yields (Q(Ln)(Ln)) equal 57 (Eu1) and 55% (Eu2). The Tb-III complexes revealed a very efficient ligand-to-metal energy transfer at room and low temperatures. (C) 2016 Elsevier B.V. All rights reserved.