Functionalized Pentamolybdodiphosphate-Based Inorganic–Organic Hybrids: Synthesis, Structure, and Properties

Three inorganic–organic hybrid compounds based on functionalized pentamolybdodiphosphonopropionate anion [(HO2CC2H4PO3)2Mo5O15]4–, [Co3(bipy)4(H2O)6{(HO2CC2H4PO3)2Mo5O15}2]·(H2bipy)2·18H2O (1), [Fe3(bipy)4(H2O)6{(HO2CC2H4PO3)2Mo5O15}2]·(H2bipy)2·18H2O (2), and [Cu­(bipy)­(H2O)2{(HO2CC2H4PO3)2Mo5O15}]·(H2bipy)·4H2O (3), where bipy = 4,4′-bipyridine, have been successfully synthesized at different pH values in aqueous solutions. In compound 1, [(HO2CC2H4PO3)2Mo5O15]4– acts as a tridentate ligand and coordinates to the Co2+ ions of trimeric complex cations [Co3(bipy)4(H2O)6]6+ forming a layer. In 3 [(HO2CC2H4PO3)2Mo5O15]4– acts as a bidentate ligand and coordinates to the Cu2+ ions of complex chains [Cu­(bipy)­(H2O)2]n2n+, forming a different layer from that in 1. The three compounds were characterized by elemental analysis, IR spectra, and TGA. In addition, their fluorescent properties and magnetic properties have also been investigated.以官能化五钼二膦酸丙酸根阴离子[(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]⁴⁻为结构基元的三种无机-有机杂化化合物，即[Co₃(bipy)₄(H₂O)₆{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}₂]·(H₂bipy)₂·18H₂O(1)、[Fe₃(bipy)₄(H₂O)₆{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}₂]·(H₂bipy)₂·18H₂O(2)与[Cu(bipy)(H₂O)₂{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}]·(H₂bipy)·4H₂O(3)（其中bipy为4,4'-联吡啶(4,4'-bipyridine)），已在水溶液体系中通过调控不同pH值成功合成。在化合物1中，[(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]⁴⁻作为三齿配体，与三聚配合物阳离子[Co₃(bipy)₄(H₂O)₆]⁶⁺中的Co²+离子配位，进而形成层状结构。在化合物3中，[(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]⁴⁻作为双齿配体，与配合物链[Cu(bipy)(H₂O)₂]ₙ²ⁿ⁺中的Cu²+离子配位，构筑得到与化合物1不同的层状结构。采用元素分析、红外光谱(IR)及热重分析(TGA)对上述三种化合物进行了结构表征；此外，还对其荧光性能与磁学性能开展了相关研究。