pH-Dependent Assembly of 1D to 3D Octamolybdate Hybrid Materials Based on a New Flexible Bis-[(pyridyl)-benzimidazole] Ligand

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• 作者：Hai-Yan Liu ; Hua Wu ; Jin Yang ; Ying-Ying Liu ; Bo Liu ; Yun-Yu Liu ; Jian-Fang Ma
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：July 6, 2011
• 年：2011
• 卷：11
• 期：7
• 页码：2920-2927
• 全文大小：1117K
• 年卷期：v.11,no.7(July 6, 2011)
• ISSN：1528-7505

文摘

Four octamolybdate hybrid materials based on a new flexible multidentate ligand, namely, H₄L(纬-Mo₈O₂₆)路2H₂O (1), [Cu(H₂L)(尾-Mo₈O₂₆)(H₂O)₂]路3H₂O (2), [Cu(H₂L)(纬-Mo₈O₂₆)]路3H₂O (3), and Cu(HL)₂(尾-Mo₈O₂₆) (4), where L is 1,1鈥?(1,4-butanediyl)bis[2-(4-pyridyl)benzimidazole], have been synthesized at different pH values under hydrothermal conditions. Compound 1, which is hydrothermally prepared at pH 鈮?1, exhibits a rare one-dimensional (1D) molybdenum oxide chain. Compounds 2 and 3 are hydrothermally obtained at pH 鈮?2.5. In 2, Cu^II cations are bridged by H₂L²⁺ ligands and (尾-Mo₈O₂₆)^{4鈥?/sup> anions to form an interesting two-dimensional (2D) layer. In 3, the H₂L2+ ligands and (纬-Mo₈O₂₆)4鈥?/sup> clusters bridge adjacent CuII cations to form a 3D framwork. When the pH value is adjusted to 3.5, compound 4 is obtained. Because the HL+ cation acts as a monodentate ligand, compound 4 only exhibits a 1D chain structure. The structural diversities of 1鈥?b>4 reveal that the pH value of the reaction system plays a crucial role in the assembly of POM-based metal鈥搊rganic frameworks (MOFs). In addition, the electrochemical property of compound 4 has also been investigated in 1 M H₂SO₄ aqueous solution.}