The antenna effect of Eu(III) cryptate entrapped in xerogel matrices

The europium(III) complex with [biq,2.2] cryptand, where big is 3.3'-biisoq uinoline-2.2'-dioxide and complexes with additional secondary ligands such as L,10-phenanthroline (phen) or triphenylphosphine oxide (TPPO) were entra pped by the sol-gel method in silica or silicate xerogel organically modifi ed with methyl groups. The photophysical properties of such materials were studied. The luminescence behaviour of the complexes in the rigid matrix wa s studied by means of emission, excitation spectra and lifetime measurement s. The results indicated that the Eu(III)-[biq,2.2] complex in the methylat ed silicate xerogel displayed a distinctly higher emission intensity and lo nger lifetime than in the silica matrix, whereas in the case of the complex es with the secondary ligands these changes were not so pronounced. It was also observed for the silica xerogel with Eu(LII) complex that the emission intensity increased up to 110 degreesC with temperature.