IN-SITU SYNTHESIS AND FLUORESCENCE CHARACTERIZATION OF 2,2'-DIPYRIDYL-EU(III) COMPLEX IN SILICA XEROGEL PREPARED BY THE SOL-GEL PROCESS

The complex of Eu(III) with 2,2'-dipyridyl is decomposed by water, and thus cannot be doped in gel glasses prepared by the sol-gel process. This paper presents a novel technique of homogeneous doping of the 2,2 '-dipyridyl-Eu(III) complex in silica gel glass. By co-doping of 2,2'- dipyridyl and Eu(III) in silica xerogel, an in situ complex of Eu(III) with 2,2'-dipyridyl is synthesized in the transparent monolithic gel glass by suitable heat treatment. Compared with a sample undergoing no heat treatment, the fluorescence intensity of Eu(III) in the xerogel heated at 100 degrees C for 24 h increases by a factor of about ten du e to the formation of the in situ 2,2'-dipyridyl-Eu(III) complex. From the fluorescence spectrum, it is suggested that the in situ complex m ay be Eu(C10H8N2)Cl-3.4H(2)O. (C) 1997 Elsevier Science S.A.