Study of new lanthanide complexes of 2,6-pyridinedicarboxylate: synthesis, crystal structure of Ln(Hdipic)(dipic) with Ln = Eu, Gd, Tb, Dy, Ho, Er, Yb, luminescence properties of Eu(Hdipic)(dipic)

This paper presents the hydrothermal synthesis of a series of new isomorphous bis-dipicolinato lanthanide complexes: Ln(Hdipic)(dipic) with Ln = Eu, Gd, Tb, Dy, Ho, Er, Yb, and dipic = 2,6-pyridinedicarboxylate. A structural study has been realised for the Ho3+ complex. It crystallises in a two-dimensional network, where sheets are parallel to the (100) plane. The luminescent properties of the analogous Eu3+ complex have been investigated. The composition of the F-7(J) levels is consistent with a true C-1 local symmetry: six oxygen and two nitrogen atoms forming a distorted square antiprism. The D-5(0) emission lifetime is only slightly shorter than in [Eu(dipic)(3)](3-) in solution, but the ligand to metal energy transfer is much less efficient. (C) 2001 Elsevier Science Ltd. All rights reserved.