Synthesis, structures and luminescent properties of 4d-4f heterometallic coordination frameworks based on lanthanide oxalate substructures with nicotinate bridging ligands

Four transition-lanthanide metal-organic coordination polymers, namely [Ag(2)Ln(nic)(4)(H2O)(4)center dot(ClO4)center dot H2O] [Ln = Eu (1), Gd (2)] and [AgLn(nic)(2)(ox)(0.5)(H2O)(2)center dot(ClO4)center dot H2O] [Ln = Tb(3), Yb (4)) (nic = nicotinate; ox = oxalate) have been synthesized by the hydrothermal reactions of 4d and 4f metal salts with N-/O-donor ligands. The isostructural complexes 1 and 2 exhibit novel 2D wave-like heterometallic layers constructed by the assembly of 1D chains of lanthanide-carboxylate with Ag(nic)(2) subunits. Complexes 3 and 4 show another unusual 3D heterometallic coordination framework constructed from 2D lanthanide-oxalate layers and pillar-like Ag(nic)2 Subunits. Furthermore, the luminescent properties of complexes 1 and 3 were studied. (C) 2008 Elsevier Ltd. All rights reserved.