Self-Recognition of Structurally Identical, Rod-Shaped Macroions with Different Central Metal Atoms during Their Assembly Process

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• 作者：Panchao Yin ; Jin Zhang ; Tao Li ; Xiaobing Zuo ; Jian Hao ; Anna Marie Warner ; Soma Chattopadhyay ; Tomohiro Shibata ; Yongge Wei ; Tianbo Liu
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：March 20, 2013
• 年：2013
• 卷：135
• 期：11
• 页码：4529-4536
• 全文大小：494K
• 年卷期：v.135,no.11(March 20, 2013)
• ISSN：1520-5126

文摘

Two rod-shaped macroanions, ((C₄H₉)₄N)₇[Mo₆O₁₈NC(OCH₂)₃XMo₆O₁₈(OCH₂)₃CNMo₆O₁₈] (X = Mn^III (1), Fe^III (2)), with almost identical charge densities and morphologies except for their different encapsulated central metal atoms were each observed to self-assemble into 鈥渂lackberry鈥?type supramolecular structures in their dilute solution, driven by the counterion-mediated attraction. Amazingly, the two macroions remained self-sorted and self-assembled into homogeneous assemblies in their mixed solutions, demonstrating a self-recognition behavior between two highly similar macroions during their assembly process, as confirmed by DLS, SLS, and TEM/EDS analysis. This self-recognition behavior can be explained by the slightly different charge distributions of the macroanions resulting from their different central atoms (confirmed by theoretical DFT calculations and dissociation experiments) and the high activation energy of the slow assembly process, which suppresses the formation of hybrid oligomers at the beginning of the self-assembly process. This work confirms that the long-range counterion-mediated electrostatic attraction is sensitive to the small difference in macroions and consequently offers the possibility for delicate selectivity and preference among different macroions. This phenomenon might be directly related to (and be the important reason for) some recognition behaviors in biological systems.