Structures, Properties, and Growth Process of Endohedral Metallofullerenes

内嵌金属富勒烯的结构、性质和生长过程

基本信息

批准号：
09440204
负责人：
NAGASE Shigeru
金额：
$ 8.77万
依托单位：
TOKYO METROPOLITAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

1. Structures, Electronic States, and Bonding Features of Endohedral MetallofullerenesThe endohedral structures of monometallofullerenes M@C_<82>(M=Ca, Sc.Y.La, Ce, Pr, Nd, Eu, Gd, Yb, and Lu) and dimetallofullerenes Sc_2@C_<84> and La_2@C_<80> have been disclosed through a close interplay between theoretical prediction and experiment. In addition, a topological analysis of electron density and its Laplacian has been carried out to reveal the general features of chemical bonding in metallofullerenes. The structural and bonding study of the trimetallfullerene Sc_3@C_<82> is still in progress.2. The Dynamic Behaviors of Encapsulated Metal AtomsFrom the variable-temperature 13CNMR measurement of La_2@C_<80>, it has been for the first time found that the two La atoms circulate with +3 charge inside the round C_<80> cage even at room temperature. This finding has been also confirmed by the variab1e-temperature 139La NMR measurement and theoretical calculations.3. Unconventional Cage Structures of Endohedral MetallofullerenesMetal atoms can stabilize unconventional structures which violate the isolated pentagon rule established in fullerene chemistry and contain heptagonal rings (thereby not obeying the traditional definition of fullerenes), during growth and annealing processes. This has been shown for Ca@C_<72> and Sc_2@C_<74>, as representative examples.4. Endohedrallly Metal-Doped Heterofullerenes.An experimental attempt to substitute one cage carbon in La@C_<82> and La_2 by one nitrogen atom has been performed to prepare La@C_<81>N and La_2@C_<79>N.it is noteworthy that these La-doped heterofullerenes have no significant radical character on the cages, unlike C_<81>N and C_<79>N.5. SummaryThe cage structures of metallofullerenes do not necessary coincide with those of the most stable fullerene isomers, because of significant electron transfer from metal to carbon cages. Most Probably, endohedral structures are formed during the annealing process.

1。内膜金属的结构，电子状态和键合的特征，单元叶列列列列列内he骨结构M@c_ c_ <82>（m = ca，sc.y.la，ce，ce，pr，nd，nd，eu，eu，eu，gd，yb，yb，yb，yb，yb，yb，yb和lu）and dimetallofullerenes sc_2@c_2@c_2@c_2@c_2@84>和la <84>和la <84>和la <84>和la <84>和cc_ <84>和cc_ <84>理论预测与实验之间的相互作用。此外，已经对电子密度及其拉普拉斯式进行了拓扑分析，以揭示金属氟烯中化学键的一般特征。 Trimetallfulerene SC_3@C_ <82>的结构和键合研究仍在进行中。2。封装金属原子的动态行为从LA_2@C_ <80>的可变温度13CNMR测量中，它首次发现两个LA原子在圆形C_ <80>笼子内，即使在室温下也有+3电荷。这一发现也通过variaB1e-temperature 139LA NMR测量和理论计算证实。3。内膜甲基叶叶烯烯基原子的非常规的笼子结构可以稳定非常规结构，这些结构违反了在富勒烯化学中建立的孤立的五角大楼规则，并含有七型环（因此，在生长和退火过程中都不遵守富勒烯的传统定义）。这已显示为CA@c_ <72>和sc_2@c_ <74>，作为代表性示例4。 Endohedrallly Metal-Doped Heterofullerenes.An experimental attempt to substitute one cage carbon in La@C_<82> and La_2 by one nitrogen atom has been performed to prepare La@C_<81>N and La_2@C_<79>N.it is noteworthy that these La-doped heterofullerenes have no significant radical character on the cages, unlike C_<81>N和C_ <79> N.5。总结金属氟烯的笼子结构与最稳定的富勒烯异构体的笼子结构不一定是由于从金属到碳笼的显着转移而相吻合的。在退火过程中很可能形成了内膜结构。