Self-assembly of a copper-ligating dendrimer that provides a new non-heme metalloprotein mimic:: "Dendrimer effects" on stability of the bis(μ-oxo)dicopper(III) core
Self-assembly of a copper-ligating dendrimer that provides a new non-heme metalloprotein mimic:: "Dendrimer effects" on stability of the bis(μ-oxo)dicopper(III) core
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DOI：
10.1021/ja982282x
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发表时间：
1999-02-03
影响因子：
15
通讯作者：
Aida, T
中科院分区：
文献类型：
--
作者：
Enomoto, M;Aida, T
树枝状聚合物是具有明确三维形状的纳米级超支化大分子，有望作为构建有组织的功能材料的基础材料。 1 最近，人们通过利用范德华力、疏水性、氢键、金属配位和静电相互作用来研究树枝状大分子的自组装，以产生明确的纳米级结构，2, 3 这些在生物超分子组装中发挥着重要作用。然而，迄今为止，表现出生物相关功能的自组装树枝状聚合物的例子非常有限。在此，我们报告了通过O2驱动的铜连接树枝状大分子自组装来模拟树状非血红素金属蛋白的第一个例子，并希望强调对焦点双（μ-氧代）二铜物种氧化自分解稳定性的明显“树枝状大分子效应”。双（μ-氧）桥双金属配合物作为甲烷单加氧酶和核糖核苷酸还原酶等多核金属蛋白活性位点的合成模型引起了广泛关注。 4 举个例子，托尔曼等人。据报道，N-取代的1,4,7-三氮杂环壬烷的Cu(I)络合物，例如[Bn3TACNCu(MeCN)]PF6(1b;Bn)苄基[图1])与O2反应形成[(Bn3TACNCu)2(μ-O)2]2+(1c)。 5 然而，由于 N-Bn 键处的氧化自分解，1c 具有热稳定性，在 10℃ 下半衰期仅为 7 s。一系列三胺核芳基醚树枝状聚合物 (Ln3TACN, n [树枝状亚基的芳香层数]) 2 (2a)、3 (3a) 和 4 (4a)；图 1) 是通过相应的氯化树枝 7 与 1, 4, 7-三氮杂环壬烷 (TACN) 的碱介导偶联合成的，并通过 1 H NMR、MALDI-TOF-MS 和元素分析进行表征。 8 抗磁性 Cu (I) 配合物 ([Ln3TACNCu (MeCN)] PF6, n) 2 (2b), 3 (3b), 4 (4b)) 是通过 2a-4a (12 mM) 与 [Cu (MeCN) 4] PF6 (12 mM) 在 CH2Cl2 中于氩气下于 20 C 反应制备的
Dendrimers are nanosized hyperbranched macromolecules with well-defined three-dimensional shapes, which are expected to serve as building blocks for the construction of organized functional materials. 1 Recently, self-assembly of dendrimers to generate well-defined nanoscale architectures have been investigated by utilization of van der Waals, hydrophobic, hydrogenbonding, metal-ligating, and electrostatic interactions, 2, 3 which play important roles in biological supramolecular assemblies. However, examples of self-asembled dendrimers which exhibit bio-related functions have been very limited to date. Herein we report the first example of a dendritic non-heme metalloprotein mimic by O2-driven self-assembly of a copper-ligating dendrimer and wish to highlight a clear “dendrimer effect” on stability of the focal point bis (μ-oxo) dicopper species toward oxidative selfdecomposition. Bis (μ-oxo)-bridged bimetallic complexes have attracted a great deal of attention as synthetic models of active sites of multinuclear metalloproteins such as methane monooxygenase and ribonucleotide reductase. 4 As an example, Tolman et al. have reported that Cu (I) complexes of N-substituted 1, 4, 7-triazacyclononanes such as [Bn3TACNCu (MeCN)] PF6 (1b; Bn) benzyl [Chart 1]) react with O2 to form [(Bn3TACNCu) 2 (μ-O) 2] 2+(1c). 5 However, 1c is thermally unstable with a half-life of only 7 s at-10 C because of an oxidative self-decomposition at the N-Bn bonds.A series of triamine-core aryl ether dendrimers (Ln3TACN, n [number of the aromatic layers of the dendron subunits]) 2 (2a), 3 (3a), and 4 (4a); Chart 1) was synthesized by alkaline-mediated coupling6 of the corresponding dendron chlorides7 with 1, 4, 7-triazacyclononane (TACN) and characterized by means of 1H NMR, MALDI-TOF-MS, and elemental analysis. 8 The diamagnetic Cu (I) complexes ([Ln3TACNCu (MeCN)] PF6, n) 2 (2b), 3 (3b), 4 (4b)) were prepared by the reaction of 2a-4a (12 mM) with [Cu (MeCN) 4] PF6 (12 mM) in CH2Cl2 under argon at 20 C