Self-Assembly of Discrete M6L8 Coordination Cages Based on a Conformationally Flexible Tripodal Phosphoric Triamide Ligand

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• 作者：Xing-Jun Li ; Fei-Long Jiang ; Ming-Yan Wu ; Shu-Quan Zhang ; You-Fu Zhou ; Mao-Chun Hong
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：April 2, 2012
• 年：2012
• 卷：51
• 期：7
• 页码：4116-4122
• 全文大小：441K
• 年卷期：v.51,no.7(April 2, 2012)
• ISSN：1520-510X

文摘

Reactions of a tripodal ligand, N,N鈥?N鈥?tris(3-pyridinyl)phosphoric triamide (TPPA), and a series of transition-metal ions result in the assembly of five discrete M₆L₈ coordination cages [M₆(TPPA)₈(H₂O)₁₂](ClO₄)₁₂路57H₂O [M = Ni²⁺ (1), Co²⁺ (2), Zn²⁺ (3), Cd²⁺ (4)] and [Pd₆(TPPA)₈]Cl₁₂路22H₂O (5). X-ray structural analyses reveal that the cages have large internal cavities and flexible windows. The flexible ligand TPPA adopts the syn conformation in cages 1鈥?b>4, but it transforms to the anti conformation in cage 5. Because of the conformational transformation, the sizes of the windows and the volume of the internal cavity of cage 5 are increased. ¹H NMR and electrospray mass spectrometric studies show that cage 5 maintains its structural integrity in solution. Additionally, compounds 3 and 4 exhibit strong blue fluorescent emissions, which are 1 order of magnitude higher than that of the free ligand.