Structural and PhotophysicalStudies on Geometric(Er2Yb2/Yb2Er2) and Configurational(EuTb3/Eu3Tb) Isomers of HeterotetranuclearLanthanide(III) Complexes.

Heterotetranuclear geometrical (Er2Yb2/Yb2Er2) and configuational (EuTb3/Eu3Tb) isomeric lanthanide(III) complexes havebeen synthesizedand characterized by spectroscopy as well as X-ray crystallography.The geometric Er2Yb2/Yb2Er2isomers exhibit dual emissions from both erbium(III) and ytterbium(III)ions. For the EuTb3/Eu3Tb configurational isomers,the TbIIIsubunits transfer energy to the EuIIIcenters in the EuTb3complex, whereas the TbIIIion in the TbEu3complex serves mainly as a structuralstabilizer. [ABSTRACT FROM AUTHOR]