Structural and Photophysical Studies on Geometric (Er2Yb2/Yb2Er2) and Configurational (EuTb3/Eu3Tb) Isomers of Heterotetranuclear Lanthanide(III) Complexes

Heterotetranuclear geometrical (Er2Yb2/Yb2Er2) and configuational (EuTb3/Eu3Tb) isomeric lanthanide­(III) complexes have been synthesized and characterized by spectroscopy as well as X-ray crystallography. The geometric Er2Yb2/Yb2Er2 isomers exhibit dual emissions from both erbium­(III) and ytterbium­(III) ions. For the EuTb3/Eu3Tb configurational isomers, the TbIII subunits transfer energy to the EuIII centers in the EuTb3 complex, whereas the TbIII ion in the TbEu3 complex serves mainly as a structural stabilizer.