Hydrothermal synthesis, crystal structure and luminescence of a europium complex with phenylmalonic acid and 1, 10-phenanthroline

A new complex Eu2(PA)6(phen)2 was prepared with hydrothermal reaction using EuCl3·6H2O, phenylmalonic acid (H2phma), and 1, 10-phenanthroline (phen), where PA was the decarboxylated product of H2phma, phenylacetate. The crystal structure of the title complex was determined with the X-ray diffraction. The title complex was a binuclear molecule with an inversion center. Each Eu3 ion was nine-coordinated with two nitrogen atoms from one phen molecule and seven oxygen atoms from five PA ligands. The carboxylic groups were bonded to the Eu3 ion in three modes, the chelating bidentate, the bridging bidentate, and the bridging-chelating tridentate. The complex emits intense red fluorescence under ultraviolet lighL The luminescence peaks correspond to the characteristic emission 5Do→7F,(J=0-4) transitions of the Eu3 ion.