Synthesis, sparkle model, intensity parameters and spectroscopic studies of the new Eu(fod)3phen-NO complex

We report the synthesis, characterization, spectroscopic properties, structure prediction and intensity parameters of the Eu(fod)(3)phen-NO (fod=6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate and phen-NO=1,10-phenanthroline N-oxide). Both the elementary analysis and the IR vibrational data are consistent with the formula of the cited complex. The absorption spectrum in ethanol shows a maximum at 272 nm, which is shifted from 293 nm in relation to Eu(fod)(3). This is an indication of the coordination of phen-NO. The emission spectra at room temperature and at 77 K show a very high intensity for the hypersensitive D-5(0) --> F-7(2) transition, pointing to a highly polarizable chemical environment around the Eu3+ ion. The complex has a decay time, tau, lower than the Eu(fod)(3)2H(2)O. It can be attributed to a considerable resonance of the ligand triplet with the excited levels of the lanthanide ion. The sparkle and INDO/S-CI models were used to calculate the structure and electronic spectrum of this complex. Good agreement between theoretical and experimental UV absorption spectra has been obtained. Structural data were used to perform theoretical predictions of the Judd-Ofelt intensity parameters (Omega(lambda),lambda = 2, 4), the D-5(0) --> F-7(0)/D-5(0) --> F-7(2) intensity ratio and D-5(0) --> F-7(1) transition splitting using the simple overlap model. The satisfactory results obtained are an indication that the models used can lead to reliable prediction of the structure and 4f-4f intensities. (C) 2003 Elsevier Science (USA). All rights reserved.