Hydrothermal synthesis and structural characterization of three novel lanthanide coordination polymers with fumarate and 1,10-phenanthroline

Three novel lanthanide complexes, [Ln(2)(fum)(3)(phen)(2)(H2O)2](n) (Ln = La, 1; Pr, 2. turn = fumarate dianion; phen = 1,10-phenanthroline) and [Er-2(fum)(3)(phen)(2)](n) (3), were synthesized hydrothermally and characterized by X-ray crystallography. Single crystal X-ray diffraction analysis shows that complex I is isostructural with 2. Ln(III) centers are nine-coordinated in I and 2 but eight-coordinated in 3 duo to lanthanide contraction. The coordination modes of fumarate and phen ligands are identical in three complexes. So structures of three complexes are very similar. In three structures, Ln(III) ions are bridged by fumarate anions in two modes, forming polymeric sheets. These sheets are further assembled into 3D supramolecular network by different intermolecular hydrogen bonding and pi-pi stacking interactions duo to the lack of coordinated water in 3. IR spectra are assigned based on the molecular structures. (C) 2004 Elsevier B.V. All rights reserved.