A Two-dimensional Gadolinium(Ⅲ)Coordination Polymer with 5-Hydroxynicotinatic Acid and Oxalate Ligands and Magnetic Property

摘要

A new coordination polymer, [Gd(Ⅲ)(3-H-5-hydroxynicotinato)(ox)1.5(H2O)2]n, has been synthesized by a hydrothermal reaction of gadolinium nitrate with 5-hydroxynicotinic acid and ammonium oxalate, and its structure has been determined by X-ray crystallography with the following data: triclinic space group Pī, C9H9NO11Gd, Mr=464.42, a=7.5545(11), b=8.1094(12), c=10.6947(16),α=103.493(2), β=98.385(2),γ=92.117(2)°, Z=2, V=628.57(16)3 , F(000)=444, Dc=2.454g.cm-3 ,μ=5.341 mm-1 , the final R=0.0188 and wR=0.0392 for 2634 observed reflections (I>2σ(I)). In the asymmetric unit of the compound, each GdⅢ ion is bonded to nine oxygen atoms from 3-H-5-hydroxynicotinato and oxalate groups and terminal-coordinated water molecules, respectively, resembling a highly distorted three-capped trigonal geometry. Adjacent GdO9 coordination polyhedra are bridged by three identical independent oxalate groups in a side-by-side manner forming brickwall-like 2D grids, and then further linked through intermolecular hydrogen bonds generating a 3D supramolecular network. Magnetic analysis of the compound shows that weak antiferromagnetic coupling exists among the adjacent GdⅢ ions.