X. Li et al., Crystal structure and luminescence of a europium nitrate complex with furancarboxylic acid and 2,2 '-bipyridine, J COORD CH, 51(2), 2000, pp. 115-123
A quaternary mixed ligand europium complex, [Eu(FA)(2)NO(3)bipy](2), has be
en synthesized, where FA = alpha-furancarboxylic acid anion and bipy = 2,2'
-bipyridine. The europium complex crystallizes in the triclinic system, spa
ce group <P(1)over bar>. Its structure was determined by X-ray diffraction
methods. The two europium ions in the dimer are held together by four carbo
xylate groups of furancarboxylic acid and each europium ion is further bond
ed to one chelated bidentate nitrate and one 2,2'-bipyridine molecule. The
coordination modes of the four carboxylate groups are divided into two type
s, bidentate bridging and tridentate bridging, making a coordination number
of 9. Excitation and luminescence spectra observed at 77 K show that the e
uropium ion site in the crystal has low symmetry and emission D-5(1) --> F-
7(J) of the Eu3+ ion disappears after 20 mu s.