Mei-Hong Chen

A 1-D chain praseodymium complex with chelidamic acid: synthesis, structure, and optical properties

The title compound [Pr(C7H3NO5)(C7H4NO5)(H2O)2] n · 1.25nH2O (1) or [Pr(HChel)(H2Chel)(H2O)2] n · 1.25nH2O, where H3Chel is 4-hydroxypyridine-2,6-dicarboxylic (chelidamic) acid, was synthesized by reaction of chelidamic acid, PrCl3 · 6H2O and H2O under hydrothermal conditions, and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that Pr is nine-coordinate with distorted tricapped trigonal prismatic coordination. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Fluorescence spectra exhibit strong green luminescence with maximum emission at 530 nm when excited with λ ex = 475 nm, originating from π–π* of the ligand.

Syntheses, structures, and optical properties of two cadmium complexes with chelidamic acid

[Cd2(C7H3NO5)2 · 4(H2O)] n · 3nH2O · 0.5n(CH3OH) (1) and [Cd3(C7H2NO5)2 · 10(H2O)] · 2H2O ·0.5CH3OH (2) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that both Cds are seven-coordinate with pentagonal bipyramid geometries. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Complex 2 is a discrete structure, then independent [Cd3(C7H2NO5)2 · 10(H2O)] are linked by hydrogen bonds into a 3-D network. The optical properties of 1 and 2 were investigated with fluorescent spectra; both exhibit strong green luminescence probably originating from π–π* transition of the ligand.

3-D Hydrogen-bonded networks of metal complexes with chelidamic acid and 1,10-phenanthroline: syntheses, structures, and optical properties

The title complexes, (C12H8N2) ⋅ [La(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 1.75H2O (1), (C12H8N2) ⋅ [Pr(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 2H2O (2), (C12H8N2)[Nd(C7H3NO5)(C7H4NO5) ⋅ 3H2O] ⋅ 2.25H2O (3), and (C12H8N2) ⋅ [Fe(C7H3NO5)(C7H4NO5)] ⋅ 2H2O (4), were synthesized and characterized by single-crystal X-ray diffraction. The crystal structures of 1–3 reveal that they are isomorphous, among which the metal atoms are all nine-coordinate with distorted tricapped trigonal prismatic coordination geometries. The Fe is six-coordinate with a distorted octahedron by two chelidamic acid ligands in 4. Complexes 1–4 are formed into 3-D networks by H-bonds and π–π stacking interactions. The fluorescence spectra of 1–3 were investigated and all exhibit strong luminescence.