【作者】 李洪光； 郝京诚； Weimin Liu；

【Author】 Hongguang Li;Weimin Liu;Jingcheng Hao;State Key Laboratory of Solid Lubrication & Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences;Key Laboratory of Colloid and Interface Chemistry & Key Laboratory of Special Aggregated Materials, Shandong University, Ministry of Education;

【机构】 中国科学院兰州化学物理研究所固体润滑国家重点实验室&清洁能源化学与材料实验室； 山东大学化学与化工学院胶体与界面化学教育部重点实验室；

【摘要】 富勒烯C₆₀是一个全碳笼分子,既疏水又疏油,结构高度对称,是构筑两亲分子的理想基元。与烷基链之间仅存在范德华力和疏水相互作用不同,C₆₀球体之间还存在较强的p-p相互作用,因此基于C₆₀的两亲分子往往表现出与传统的含烷基链两亲分子迥异的自组装特性。不仅如此,由于C₆₀自身具有优异的物理化学性能,含C₆₀两亲分子还能够自组装形成具有特定功能的超分子体系。我们以C₆₀为疏水（油）组分,通过[3+2]环加成反应,将其与多种亲水、亲油或亲极性有机溶剂的功能基团连接,构筑了一系列结构新颖的两亲分子,如Fig. 1所示。以亲水的寡聚氧乙烯修饰C₆₀,得到了六种C₆₀中性两亲分子（Fig.1A）;通过进一步季铵化,得到了季铵阳离子和寡聚氧乙烯共修饰的C₆₀两亲分子（Fig. 1B）,进一步提高了其水溶性。研究发现,此类分子在水溶液中能够形成囊泡、纳米片、纤维等自组装结构[1]。以具有刚性骨架的金刚烷来修饰C₆₀,制备了1:1和2:1型金刚烷-C₆₀两亲分子（Fig.1C）,由于金刚烷与C₆₀疏水性的差异,金刚烷-C₆₀两亲分子在有机溶剂如氯仿中亦能够形成纳米圆盘、纳米球等有序聚集结构。同时,若以DMSO、丙酮等不良溶剂进行调控,还能够获得纳米花、纳米纤维、具有粗糙表面的纳米球等丰富的超分子自组装结构。此外,我们以具有磁性的纳米团簇多金属氧酸盐（POMs）来修饰C₆₀,得到了一类结构新颖的含C₆₀有机-无机两亲分子（Fig. 1D）,发现在多种极性有机溶剂中,此类两亲分子可以自组装形成具有磁性和光动力活性的多层囊泡[2]。上述工作拓宽了两亲分子结构的多样性,对深刻理解具有特殊结构两亲分子的自组装行为提供了素材,为含C₆₀超分子体系在信息存储、光电器件、生物医药等领域的应用奠定了基础。更多还原

【Abstract】 Fullerene C₆₀ is a cage molecule formed solely by carbon atoms. Being both hydrophobic and oleophobic as well as highly symmetric, C₆₀ can be viewed as an ideal building block for the construction of amphiphiles. Unlike the alkyl chains among which van der Waals forces and hydrophobic-hydrophobic interactions are dominant, additional p-p interaction exists among the C₆₀ moieties. Thus, the self-assembly characteristics of C₆₀-based amphiphiles could differ from those exhibited by traditional amphiphiles containing alkyl chains. In addition, due to the exciting physicochemical properties from C₆₀, it is possible to construct supramolecular systems with specific functions by using C₆₀-based amphiphiles through self-assembly. In our work, C₆₀ is selected as a hydrophobic and/or oleophobic part, to which a variety of functional groups that are hydrophilic, oleophilic or compatible with polar organic solvents were grafted through [3+2] cycloaddition to yield a series of amphiphiles with novel molecular structures, as shown in Fig. 1. By attaching oligo-poly（ethylene oxide）（o-PEO） chain（s） to C₆₀, six C₆₀-based neutral amphiphiles can be obtained（Fig. 1A）. To further improve the water solubility, C₆₀-based amphiphiles co-functionalized by o-PEO and quaternary ammonium cation are synthesized via one-step quaternization. It was found that the neutral and ionic o-PEO-C₆₀ amphiphiles can self-assembly into vesicles, nanoplates and fibers in aqueous solutions. Being a rigid molecule, adamantane（Ad） can be also selected as the functional group to modify C₆₀, yielding 1:1 and 2:1 Ad-C₆₀ amphiphiles（Fig. 1C）. Driven by the different hydrophobicity between Ad and C₆₀, the Ad-C₆₀ amphiphiles can self-assembly into nanodiscs and nanospheres in a given organic solvent such as chloroform. If tuned by poor solvent such as DMSO and acetone, more superstructures can be obtained including nanoflowers, nanofibers and nanospheres with rough surfaces. We have also used polyoxometallates（POMs） to functionalize C₆₀, which leads to the formation of a novel type of C₆₀-based organic-inorganic amphiphiles（Fig. 1D）. It was found that such amphiphiles can self-assembly into multilamellar vesicles with magnetic and photodynamic properties in a variety of polar organic solvents. The work mentioned above enriches the family of amphiphiles and provides necessary materials to deep understanding the characteristics involved in the self-assembly of amphiphiles with unique structures. It can also lay the foundation for the applications of C₆₀-based supramolecular systems in information storage, photoelectronic devices and biological medicine.更多还原