Abstract The synthesis, spectral characterization, crystal structure and properties of [Ba(H2O)2(NMF)2(4-nba)2], 1 (NMF = N-methylformamide; 4-nba = 4-nitrobenzoate), are reported. 1H and 13C NMR spectral data reveal the presence of NMF in 1. A strong band at 1660 cm−1 in the infrared spectrum indicates the binding of amide oxygen to Ba(II) which is confirmed by the single crystal structure. The unique Ba(II) in 1 situated on a mirror plane exhibits nine coordination and is bonded to two symmetry related monodentate terminal NMF ligands via the amide oxygen, and a terminal aqua ligand. The μ2-monoatomic bridging binding mode of each of a crystallographically independent 4-nba ligand and a unique water ligand link the Ba(II) cations into an infinite chain extending along a, leading to the formation of a 1D coordination polymer with Ba···Ba separations of 4.2522(3) Å. In the chain, the {BaO9} polyhedra are linked in a face sharing fashion. Thermal decomposition of 1 results in the formation of BaCO3 residue. A comparative study of the structural chemistry of several barium coordination polymers is described. Graphical Abstract

中文翻译：

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基于 μ2-单原子桥连 4-硝基苯甲酸酯的钡配位聚合物的合成和结构表征

摘要 报道了[Ba(H2O)2(NMF)2(4-nba)2], 1 (NMF = N-甲基甲酰胺；4-nba = 4-硝基苯甲酸酯)的合成、光谱表征、晶体结构和性质。1H 和 13C NMR 光谱数据显示 1 中存在 NMF。红外光谱中 1660 cm-1 处的强带表明酰胺氧与 Ba(II) 结合，这由单晶结构证实。位于镜面上的独特 Ba(II) in 1 具有九个配位，并通过酰胺氧与两个对称相关的单齿末端 NMF 配体和一个末端水配体键合。晶体学上独立的 4-nba 配体和独特的水配体的 μ2-单原子桥接结合模式将 Ba(II) 阳离子连接成沿 a 延伸的无限链，导致形成一维配位聚合物，Ba…Ba 分离度为 4.2522(3) Å。在链中，{BaO9} 多面体以面部共享的方式链接。1 的热分解导致形成 BaCO3 残留物。描述了几种钡配位聚合物的结构化学的比较研究。图形概要