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

Heterotetranuclear geometrical (Er 2 Yb 2 /Yb 2 Er 2 ) and configuational (EuTb 3 /Eu 3 Tb) isomeric lanthanide(III) complexes have been synthesized and characterized by spectroscopy as well as X-ray crystallography. The geometric Er 2 Yb 2 /Yb 2 Er 2 isomers exhibit dual emissions from both erbium(III) and ytterbium(III) ions. For the EuTb 3 /Eu 3 Tb configurational isomers, the Tb III subunits transfer energy to the Eu III centers in the EuTb 3 complex, whereas the Tb III ion in the TbEu 3 complex serves mainly as a structural stabilizer.