内嵌放射性金属同位素富勒烯的制备及生物学研究

综述了内嵌放射性金属同位素富勒烯的制备及医用研究现状。内嵌金属富勒烯的制备目前主要采用电弧放电法,但产率还较低;而放射性内嵌金属富勒烯的合成,主要是利用镧系区域的钬、钐和镥等具有合适的中子捕获截面及适当的半衰期的元素首先由电弧法制备,然后在中子的辐照下形成。因中子辐照会破坏碳笼,故放射性内嵌金属富勒烯的产率更低。动物实验是利用BALB/c小鼠和Fischer大鼠进行活体代谢实验,结果表明,放射性钬内嵌金属富勒烯主要分布于骨骼和肝脏,毒性低而靶向性高。放射性内嵌金属富勒烯有望成为新型放射性药物或示踪剂。     

GdNi2合金选择性合成Gd金属包合物和单壁碳纳米管

以GdNi2合金为金属源,采用电弧放电法,控制不同的He压选择性地合成了Gd金属富勒烯包合物和单壁碳纳米管.当He压为16kPa时,主要得到Gd金属富勒烯包合物,当He压为80kPa时,选择性获得单壁碳纳米管.     

大碳笼内嵌钆氧化物团簇金属富勒烯Gd_2O@C_(88):实验和理论研究

利用改进的电弧放电技术合成及多步高效液相色谱(HPLC)分离方法,得到了大碳笼含钆氧化物团簇的金属富勒烯Gd_2O@C_(88).激光解吸电离碰撞诱导解离质谱/质谱的研究结果表明,氧化钆团簇位于碳笼内部.密度泛函理论计算结果表明,金属富勒烯结构为Gd_2O@D_2(35)-C_(88).内嵌团簇向碳笼转移4个电子,价态+4,碳笼-4价,金属富勒烯的电子结构表示为[Gd_2O]~(4+)@[D_2(35)-C_(88)]~(4-).     

内嵌金属富勒烯的电子自旋研究进展

内嵌金属富勒烯(EMFs)由于其独特的笼状嵌套结构而受到研究者的关注,富勒烯碳笼的保护使得内嵌金属离子或团簇显示出与众不同的电子结构及自旋特性,在量子信息处理、高密度信息存储及量子调控等方面具有重要的应用价值。主要介绍了具有电子自旋活性的内嵌金属富勒烯的研究进展,分析了其电子结构及自旋特性;进一步讨论了目前进行金属富勒烯电子自旋调控的方法,如改变温度、笼外修饰及构筑自组装体等,通过研究富勒烯分子的电子自旋特性来探究分子的运动状态,为构筑基于富勒烯的量子体系奠定基础。     

金属氮化物合成方法的研究进展

介绍了近年来金属氮化物的5种主要合成方法：程序升温法、热分解法、固态反应法、电化学法和球磨制备法，着重阐述了每种合成方法的研究现状及其优缺点，并对金属氮化物合成方法的发展前号进行了展望，认为开发工艺简单、操作条件温和、氮化产物成本低廉、产物结构易于控制的合成方法是未来发展的必然趋势。     

中科院化学所在富勒烯衍生化研究方面取得系列新进展

对富勒烯和金属富勒烯进行笼外修饰能够调控这类功能分子的电子结构性能,是富勒烯化学重要的研究领域之一。最近,在中国科学院、国家自然科学基金委和科技部973项目的大力支持下,中科院化学所分子纳米结构与纳米技术院重点实验室科研人员与厦门大学科学家合作,在富勒烯和内嵌金属富勒烯衍生化方面取得了系列新研究成果,     

金属富勒烯包合物衍生物的合成进展

综述了近年来对合成金属富勒烯包合物衍生物的研究进展.Diels-Alder、1,3-偶极、硅烷化、羟基化、Bingel-Hirsch等是合成金属富勒烯包合物衍生物的主要方法,而碳笼内包合的簇的种类不同程度上影响着化学反应过程和金属富勒烯包合物衍生物的性能,这些金属富勒烯包合物衍生物所具有的新性能,在医药、材料和电子器件具有广阔的应用前景,同时展望了今后的工作.     

碳纳米洋葱制备方法的研究进展

碳纳米洋葱是继富勒烯与碳纳米管之后的又一新型碳纳米材料,在润滑剂、磁性材料等领域具有广阔的应用前景.综述了碳纳米洋葱的主要合成方法(电弧放电法、等离子体法、电子束照射法、热处理法、热解法和化学气相沉积法)及其特点,讨论了碳洋葱的形成机理,并简单介绍了碳纳米洋葱的性能及其应用.     

富勒烯C60的制备研究Ⅰ最佳制备条件的确定

以石墨、煤基炭为原料,电弧法制备富勒烯。考察了富勒烯的最佳制备条件,并对电弧蒸发下富勒烯的形成机理进行了讨论。实验结果表明,在电弧法制备富勒烯的过程中,一个适宜的温度场分布对于提高富勒烯的产率是很重要的,在本实验条件下,富勒烯的最佳制备条件为：氦气压力Ｐ＝ ０．０１８ ＭＰａ～０．０２ ＭＰａ,直流电流强度Ｉ＝ ８０ Ａ～１００ Ａ。     

静态氮气氛中合成金属氮化物

提出了在高温和静态氮气氛下利用金属与氮气直接反应制取金属氮化物的合成方法.通过选择不同的反应条件,用该方法合成了从活泼金属(如Li、Mg、La、Ce和Al)到过渡金属(如Ti、Zr、V、Nb和Cr)等10种二元氮化物.时所得氮化物进行XRD物相分析表明,所得产物均以二元氮化物为主相,杂相含量很少.用扫描电镜(SEM)观察了AIN、TiN和VN样品的表面形貌,EDX分析表明,它们的化学组成与名义成分基本一致.与其它氮化物合成方法相比,静态氮气中直接氮化的合成方法具有节省资源和环境友好的优点.     

Metal nitride cluster fullerenes: their current state and future prospects

The world of endohedral fullerenes was significantly enlarged over the past seven years by the cluster fullerenes, which contain structures such as the M(2)C(2) carbides and the M(3)N nitrides. While the carbide clusters are generated under the standard arc-burning conditions according to stabilization conditions, the nitride cluster fullerenes (NCFs) are formed by varying the composition of the cooling gas atmosphere in the arc-burning process. The special conditions for NCF synthesis is described in detail and the optimum conditions for the production of NCFs as the main product in fullerene syntheses are given. A general review of all NCFs reported to date consists of the structures, properties, and stability of the NCFs as well as the abundance of the NCFs in the fullerene soot. It is shown that all cages with even carbon atoms from C(68) to C(98) are available as endohedral nitride cluster structures (with the exception of C(72), C(74), and C(76)). Specifically, the NCFs form the largest number of structures that violate the isolated pentagon rule (IPR). Finally some practical applications of these cluster fullerenes are illustrated and an outlook is given, taking the superior stability of these endohedral fullerenes into account.     

A density functional theory investigation for the open-shell metal-carbide endofullerene Lu3C2@C88(D2:35) and closed-shell metal-nitride endofullerene Lu3N@C88(D2:35)

By means of the density functional theory calculations, two C88(D2:35)-based endohedral fullerenes, Lu3C2@C88(D2:35) and Lu3N@C88(D2:35) which encapsulate tri-lutetium carbide and tri-lutetium nitride cluster were investigated. For the cores in Lu3C2@C88 and Lu3N@C88, the trivalent C2 and N respectively template a butterfly-shaped endohedral moiety and a planar tri-lutetium cluster within the same D2-symmetric C88 cage. Moreover, Lu3N@C88 - D2 has a closed-shell electronic structure but for LuC3C2@C88 - D2, it owns an unpaired electron mainly localized on the internal Lu3C2 cluster. These results clearly showed that the core unit C2(3) as well as N3- play an important role in constructing molecular structures and electronic features of metallofullerenes. Furthermore, the electrochemical redox potentials, and vibrational frequencies of the two endofullerenes agree well with our experimental results. The electronic structures, ionization energies, electron affinities, inner clusters' dynamic motions of them have been predicted to further disclose the characters of these two metallofullerenes.     

内包金属富勒烯C_(66)-C_(84)团簇的结构特征

从富勒烯笼五六元环的分布情况评述了内包单金属、双金属、三金属以及三金属氮化物(M_3N)和碳化物(M_2C_2)富勒烯C_(66)～C_(84)团簇的结构特征.富勒烯满足五元环最大分离规则,内包不同类型的金属团簇不仅改变了笼的稳定性顺序,也使C_(66)、C_(68)、C_(70)、C_(72)、C_(74)、C_(78)和C_(84)的部分异构体违背五元环最大分离规则 .     

Controlled synthesis of fullerenes and endohedral metallofullerenes in high frequency arc discharge

The article presents the high-frequency arc discharge setup operating in helium atmosphere and applicable for the syntheses of carbon condensate with different dispersion and structure, along with fullerenes and endohedral metallofullerenes. It also highlights how the change of helium pressure in chamber can control the amount and composition of products in carbon condensate. The setup can be applied for the purposes of analysis, for instance in order to obtain information about the process of fullerenes and endohedral met-allofullerenes formation. Also, the fact that the yield of higher fullerenes is increasing with the pressure rise, whereas the yield of endohedral metallofullerenes is decreasing suggests different formation mechanisms.     

Modeling the structure of fulleranes and their endohedral complexes involving small molecules with nontrivial topological properties

'In' and 'out' isomers of perhydrogenated fullerenes and endohedral fullerene complexes have only recently been incorporated into the realm of topological chemistry. The 'in' isomers are, until now, purely hypothetical while for the latter group mostly studied are the complexes with metal ions that can be obtained during the fullerenes manufacturing. Much more difficult to obtain are the complexes with small molecules buried inside fullerene cages produced by laborious synthesis involving opening the cage, inserting the guest into it, and closing the cage chemically. This complicated procedure has only recently been accomplished for a hydrogen molecule put in the C60. Two H2 molecules inside the opened C70 cage and H2O in the opened C60 have been also reported recently. Model calculations, when carefully applied, allow one to predict the possibility of obtaining endohedral fullerene complexes with small molecules and 'in' isomers of perhydrogenated fullerenes. However, such systems are too large to be reliably handled by quantum calculations. Interestingly, such a simple method as molecular mechanics seems much more trustworthy.     

Water-soluble fullerenes for medical applications

Research on fullerenes occupies a unique position in the scientific arena. Synthesis and characterisation of this nanomaterial blur the line between materials science and chemistry; careful tuning of the processing methods gives birth to a whole family of molecules and their functionalised derivatives, whose unusual properties at this nanoscopic scale can be exploited in cutting-edge technological applications. This review focuses on the functionalisation of fullerenes for use in medical applications. The first half gives an introduction to the fullerenes themselves and how their fundamental properties lead to a very rich chemistry, enabling both exohedral (external) and endohedral (internal) functionalisations of the cage. Emphasis is placed on the need for safe and reproducible synthesis routes if fullerenes are ever going to make it to the pharmaceutical market. In line with this, a selection of exohedral functionalisation protocols receives particular attention. Coverage of endohedral fullerene synthesis routes is limited to the endohedral metallofullerenes. In the second half, myriad applications of fullerenes in biomedical contexts are introduced and certain synthesis routes are critically evaluated. Discussion of the need to water solubilise the hydrophobic fullerene cages precedes an overview of fullerene-based diagnostic and therapeutic technologies. A final moment is spent on toxicity studies of fullerenes. The concluding remarks emphasise the positive effects of incorporating fullerenes into biomedical technologies, while looking at how these are perceived by the general public. A case is made for fullerenes being the optimal choice as standard bearers in the advance of nanomaterials into the medical field.

This is the winning review of the 2016 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining, run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged.     

A method and apparatus for high-throughput controlled synthesis of fullerenes and endohedral metal fullerenes

A method for synthesis of carbon nanostructures in a high-frequency arc discharge in the flow of helium (3–4 L/min) is presented. It is shown that the plasma-chemical synthesis of fullerenes and endohedral metal fullerenes (EMFs) can be controlled by changing helium pressure in the chamber. Temperature and electron concentration along the line normal to the discharge axis decrease upon moving away from the axis to the periphery; the larger the pressure, the sharper is the decrease in these parameters. The optimal helium pressure of 98 kPa was found in obtaining the Gd@C₈₂ EMF which corresponds to the maximal EMF yield of 5 wt %.     

NMR Studies of the Dynamic Motion of Encapsulated Ions and Clusters in Fullerene Cages: A Wheel Within a Wheel

Nuclear magnetic resonance (NMR) has provided an important approach to investigate the structure and dynamics of encapsulated metal ions and clusters in endohedral metallofullerenes (EMFs). In this paper, we review NMR studies of the environment and dynamics of dimetallic, trimetallic nitride, metal carbide and metal cyanide clusters encapsulated in EMFs. The NMR chemical shielding parameter is a sensitive probe for monitoring the carbon cage (¹³C) and encapsulated clusters (¹³C, ¹⁴N, ¹³⁹La, ⁴⁵Sc, and ⁸⁹Y). Future NMR EMF studies could be very fruitful and help elucidate coupled motion between the carbon cage and encapsulated cluster or other “wheel within a wheel” motional processes.     

Radiochemical approaches for formation of endohedral fullerenes and MD simulation

The formation of atom-doped fullerenes has been investigated by using several types of radionuclides produced by nuclear reactions. From the trace of the radioactivities after a high performance liquid chromatography, it was found that formation of endohedral fullerenes (or heterofullerenes) of small atoms (Be, Li), noble-gas atoms (Kr, Xe) and 4B–6B elements (Ge, As, Se, Sb, Te, etc.) is possible by a recoil process following the nuclear reaction. In order to show the possibility of creating endohedral fullerenes with a suitably high kinetic energy of foreign atoms, we have carried out large-scale ab initio molecular dynamics simulations on the basis of the all-electron mixed-basis approach with atomic orbitals and plane waves for several atoms.