Krause Matthias, Liu Xianjie, Wong Joanna, Pichler Thomas, Knupfer Martin, Dunsch Lothar
Leibniz-Institute for Solid State and Materials Research Dresden, Institute of Solid State Research, Group of Electrochemistry and Conducting Polymers, P. O. box 27 01 16, D-01171 Dresden, Germany.
J Phys Chem A. 2005 Aug 18;109(32):7088-93. doi: 10.1021/jp0525080.
The electronic and vibrational structure of the nitride clusterfullerene Tm3N@C80 (I) was investigated by cyclic voltammetry, FTIR, Raman, and X-ray photoemission spectroscopy. The electrochemical energy gap of Tm3N@C80 (I) is 1.99 V, which is 0.13 V larger than that of Sc3N@C80 (I). FTIR spectroscopy showed that the C80:7 (I(h)) cages in Tm3N@C80 (I), Er3N@C80 (I), Ho3N@C80 (I), Tb3N@C80 (I), Gd3N@C80 (I), and Y3N@C80 (I) have the same bond order. The analysis of low-energy Raman spectra points to two uniform force constants which can be used to describe the interaction between the encaged nitride cluster and the C80:7 (I(h)) cage in M3N@C80 (I) (M = Tm, Er, Ho, Tb, Gd, and Y). Because the M3N-C80 bond strength is strongly dependent on the charge of the metal ions, this is a direct hint for a 3+ formal valence state of the metal ions in these nitride clusterfullerene series, including Tm3N@C80 (I). Photoemission spectra of the Tm 4d core level and the Tm 4f valence electrons provided a direct proof for a (4f)12 electronic configuration of the encapsulated thulium. In conclusion, thulium in Tm3N@C80 (I) has a formal electronic ground state of +3, in contrast to the +2 state found in Tm@C82. It is demonstrated that the valence state of metal atoms encaged in fullerenes can be controlled by the chemical composition of the endohedral fullerene.
通过循环伏安法、傅里叶变换红外光谱（FTIR）、拉曼光谱和X射线光电子能谱对氮化物团簇富勒烯Tm3N@C80 (I)的电子结构和振动结构进行了研究。Tm3N@C80 (I)的电化学能隙为1.99 V，比Sc3N@C80 (I)的电化学能隙大0.13 V。FTIR光谱表明，Tm3N@C80 (I)、Er3N@C80 (I)、Ho3N@C80 (I)、Tb3N@C80 (I)、Gd3N@C80 (I)和Y3N@C80 (I)中的C80:7 (I(h))笼具有相同的键级。低能量拉曼光谱分析指出了两个统一的力常数，可用于描述包封的氮化物团簇与M3N@C80 (I)（M = Tm、Er、Ho、Tb、Gd和Y）中的C80:7 (I(h))笼之间的相互作用。由于M3N-C80键强度强烈依赖于金属离子的电荷，这直接暗示了这些氮化物团簇富勒烯系列（包括Tm3N@C80 (I)）中金属离子的形式价态为3+。铥4d芯能级和铥4f价电子的光电子能谱为包封铥的(4f)12电子构型提供了直接证据。总之，与Tm@C82中发现的+2价态相比，Tm3N@C80 (I)中的铥具有形式电子基态+3价。结果表明，富勒烯包封的金属原子的价态可通过内包富勒烯的化学成分来控制。
