Institut de Química Computacional and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain.
Phys Chem Chem Phys. 2011 Mar 7;13(9):3585-603. doi: 10.1039/c0cp01594f. Epub 2010 Nov 25.
The last two decades have witnessed major advances in the synthesis and characterization of endohedral fullerenes. These species have interesting physicochemical properties with many potential interesting applications in the fields of magnetism, superconductivity, nonlinear optical properties, radioimmunotherapy, and magnetic resonance imaging contrast agents, among others. In addition to the synthesis and characterization, the chemical functionalization of these species has been a main focus of research for at least four reasons: first, to help characterize endohedral fullerenes that could not be well described structurally otherwise; second, to generate materials with fine-tuned properties leading to enhanced functionality in one of their multiple potential applications; third, to produce water-soluble endohedral fullerenes needed for their use in medicinal sciences; and fourth, to generate electron donor-acceptor conjugates that can be used in solar energy conversion/storage. The functionalization of these species has been achieved through different types of reactions, the most common being the Diels-Alder reactions, 1,3-dipolar cycloadditions, Bingel-Hirsch reactions, and free-radical reactions. It has been found that the performance of these reactions in endohedral fullerenes may be quite different from that of the empty fullerenes. Indeed, encapsulated species have a large influence on the thermodynamics, kinetics, and regiochemistry of these reactions. A detailed understanding of the changes in chemical reactivity due to incarceration of atoms or clusters of atoms is essential to assist the synthesis of new functionalized endohedral fullerenes with specific properties. This Perspective seeks to highlight the key role played by computational chemistry in the analysis of the chemical reactivity of these systems. It is shown that the information obtained through calculations is highly valuable in the process of designing new materials based on endohedral fullerenes.
在过去的二十年中,内包富勒烯的合成和表征取得了重大进展。这些物种具有有趣的物理化学性质,在磁性、超导性、非线性光学性质、放射性免疫治疗和磁共振成像对比剂等领域具有许多潜在的有趣应用。除了合成和表征外,这些物种的化学功能化一直是研究的主要焦点,原因至少有四个:首先,帮助描述其他结构方法无法很好描述的内包富勒烯;其次,生成具有微调性质的材料,从而增强其多种潜在应用中的功能;第三,生产用于医学科学的水溶性内包富勒烯;第四,生成可用于太阳能转换/存储的电子供体-受体轭合物。这些物种的功能化是通过不同类型的反应实现的,最常见的是 Diels-Alder 反应、1,3-偶极环加成反应、Bingel-Hirsch 反应和自由基反应。已经发现,这些反应在内包富勒烯中的性能可能与空富勒烯中的性能有很大不同。事实上,被包裹的物种对这些反应的热力学、动力学和区域化学有很大的影响。深入了解由于原子或原子团的囚禁而导致的化学反应性变化,对于协助合成具有特定性质的新型功能化内包富勒烯至关重要。本文旨在强调计算化学在分析这些体系的化学反应性方面所起的关键作用。结果表明,通过计算获得的信息在基于内包富勒烯设计新材料的过程中具有很高的价值。