Eu3+ and Tb3+ organophosphonates:: synthesis, characterization and luminescent properties

This paper reports the results for the synthesis, characterization and photophysical properties of EuH(O3PR)(2) and ToH(O3PR)(2) (R=CH3 or C6H5). The Eu3+ luminescence data revealed highly red emissive materials where the characteristic transitions D-5(0)-->F-7(J) (J=1, 2, 3, and 4) of Eu3+ were observed when they were excited at 378 nm. The lifetime (lambda(EXC) = 378 nm) for EuH(O3PC6H5)(2) (lambda(EM)=614.5 nm) is 1.95 ms and for EuH(O3PCH3)(2) (lambda(EM)=610.5 nm) is 1.75 ms. Tb3+ compounds presented a highly green luminescence when excited at 368 nm due to the Tb3+ D-5(4)-->F-7(J) (J=6, 5, 4, and 3) transitions. The Tb3+ lifetime (lambda(EXC)=368 nm, lambda(EM)=544 nm) for TbH(O3PC6H5)(2) is 2.59 and 2.88 ms for TbH(O3PCH3)(2). The emission spectra of the solids resulting from TGA/DTA showed a Eu3+ D-5(0)-->F-7(1) transition more intense than the D-5(0)-->F-7(2) one. The decrease in the 0-->2/0-->1 ratio from 2.92 to 0.503 for EuH(O3PCH3)(2) and from 3.19 to 0.881 for EuH(O3PC6H5)(2), is consistent with a higher symmetry around Eu3+. (C) 1998 Elsevier Science S.A.