Two novel erbium (III) coordination polymers with 5-nitroisophthalic acid: Syntheses and crystal structures and thermal stabilities

Two new coordination polymers, {[Er(5-nip)1.5(2,2′-bipy)](H2O)2}n (1) and {[Er(5-nip)2] (4,4′-H2bipy)0.5}n (2) (5-nip = 5-nitroisophthalic acid, 2,2′-bipy = 2,2′-bipyridyl, 4,4′-bipy = 4,4′-bipyridyl), have been synthesized by the hydrothermal reactions of erbium nitrate, 5-nitroisophthalic acid (5-H2nip) and 2,2′-bipyridyl (for 1), and erbium nitrate, 5-nitroisophthalic acid and 4,4′-bipyridyl (for 2). X-ray diffraction analysis indicates that complex 1 exhibits a two-dimensional layer structure, while complex 2 displays a 3D architecture sustained by the strong hydrogen-bond interactions between the protonated 4,4′-bipyridyl and the carboxyl oxygen atom from [Er2(5-nip)4]2− with 2D layer structure, and 4,4′-bipyridyl as the guest molecules exist in bilayer channel. They are characterized by the elemental analysis and IR spectroscopy. The studies for the thermal stabilities of the two complexes show that complex 2 is more stable than complex 1.

Graphical abstractTwo new coordination polymers {[Er(5-nip)1.5(2,2′-bipy)](H2O)2}n (1) and {[Er(5-nip)2] (4,4′-H2bipy)0.5}n (2) have been synthesized by the hydrothermal reactions, in which complex 1 exhibits a two-dimensional layer structure, while complex 2 displays a 3D architecture sustained by the strong hydrogen-bond interactions between the protonated 4,4′-bipyridyl as the guest molecules and the carboxyl oxygen atom from [Er2(5-nip)4]2− with 2D layer structure.Figure optionsDownload full-size imageDownload as PowerPoint slide