Guanidinium as powerful cation for the design of lanthanate tris-dipicolinate crystalline materials:: Synthesis, structure and photophysical properties

This article reports the synthesis, the structures and the photophysical properties of various lanthanate tris-dipicolinate complexes featuring guanidinium (Gua) as counter-cation (Ln = La, Ce, Eu, Tb, Dy, Tm). The X-rays crystal structure of [Gua](3)[Ce(DPA)(3)]center dot 3H(2)O is described and compared to that of [Na](3)[Ce(DPA)(3)]center dot 14H(2)O. The particular case of Cerium, the only yellow complex, is studied by absorption spectroscopy and cyclic voltammetry, and finally the emission properties of lanthanides complexes emitting in the visible spectral range (Eu, Tb, Dy, Tm) are studied in solution as in crystalline materials. (c) 2007 Elsevier B.V. All rights reserved.