Synthesis, crystal structures and photoluminescence of Zn–Ln heterometallic polymers based on pyridine-2,3-dicarboxylic acid

• Published in: Inorganic chemistry communications 2009-08, Vol.12 (8), p.761-765
• Main Authors: Chen, Li, Lin, Xiao-Ming, Ying, Yin, Zhan, Qing-Guang, Hong, Ze-Hong, Li, Jun-Yong, Weng, Ng Seik, Cai, Yue-Peng
• Format: Article
• Language: English
• Subjects: 3d–4f heterometallic complex; Crystal structures; Luminescence; Pyridine-2,3-dicarboxylic acid; Synthesis and characterization
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2009.06.009

Three new two-dimensional 3d–4f isostructural heterometallic coordination polymers, namely [Ln 2Zn(2,3-pydc) 4(H 2O) 4·4H 2O] n (Ln = Sm ( 1), Eu ( 2), Gd ( 3), 2,3-pydcH 2 = pyridine-2,3-dicarboxylic acid) have been successfully synthesized by the hydrothermal reactions of Ln 2O 3, Zn(NO 3) 2·6H 2O, H 2pydc and H 2O. X-ray diffraction analyses reveal that they possess a 2D heterometallic framework containing 1D lanthanide chains based on dimeric [Ln(2,3-pydc) 2(H 2O) 2] 2 unit. The Zn(II) ion, which is six-coordinated by four oxygen and two nitrogen atoms from four 2,3-pydc 2− ligands, as a inter-chain spacer, links the lanthanide chains to make the 1D chains further extend into 2D layer framework. Furthermore, the neighboring layers are assembled into three-dimensional supramolecular network through inter-layer O–H⋯O and C–H⋯O hydrogen-bond interactions. In addition, the solid-state luminescent property of complex 2 was investigated. Three new two-dimensional 3d–4f isostructural heterometallic coordination polymers, namely [Ln 2Zn(2,3-pydc) 4(H 2O) 4·4H 2O] n (Ln = Sm ( 1), Eu ( 2), Gd ( 3), 2,3-pydcH 2 = pyridine-2,3-dicarboxylic acid) have been successfully synthesized by the hydrothermal reactions of Ln 2O 3, Zn(NO 3) 2·6H 2O, H 2pydc and H 2O. X-ray diffraction analyses reveal that they possess a 2D heterometallic framework containing 1D lanthanide chains based on dimeric [Ln(2,3-pydc) 2(H 2O) 2] 2 unit. The Zn(II) ion, which is six-coordinated by four oxygen and two nitrogen atoms from four 2,3-pydc 2− ligands, as a bridge, links the lanthanide chains to make the 1D chains further extend into 2D layer framework. Furthermore, the neighboring layers are assembled into three-dimensional supramolecular network through inter-layer O–H⋯O and C–H⋯O hydrogen-bond interactions. In addition, the solid-state luminescent property of complex 2 was investigated.