Koyasu Kiichirou, Atobe Junko, Akutsu Minoru, Mitsui Masaaki, Nakajima Atsushi
Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522, Japan.
J Phys Chem A. 2007 Jan 11;111(1):42-9. doi: 10.1021/jp066757f.
Silicon clusters mixed with a transition metal atom, MSin, were generated by a double-laser vaporization method, and the electronic and geometric stabilities for the resulting clusters with transition metal encapsulated by silicon were examined experimentally. By means of a systematic doping with transition metal atoms of groups 3, 4, and 5 (M = Sc, Y, Lu, Ti, Zr, Hf, V, Nb, and Ta), followed by changes of charge states, we explored the use of an electronic closing of a silicon caged cluster and variations in its cavity size to facilitate metal-atom encapsulation. Results obtained by mass spectrometry, anion photoelectron spectroscopy, and adsorption reactivity toward H2O show that the neutral cluster doped with a group 4 atom features an electronic and a geometric closing at n = 16. The MSi(16) cluster with a group 4 atom undergoes an electronic change in (i) the number of valence electrons when the metal atom is substituted by the neighboring metals with a group 3 or 5 atom and in (ii) atomic radii with the substitution of the same group elements of Zr and Hf. The reactivity of a halogen atom with the MSi(16) clusters reveals that VSi(16)F forms a superatom complex with ionic bonding.
通过双激光蒸发法生成了与过渡金属原子混合的硅团簇MSin，并对所得硅包裹过渡金属团簇的电子稳定性和几何稳定性进行了实验研究。通过对3、4、5族过渡金属原子（M = Sc、Y、Lu、Ti、Zr、Hf、V、Nb和Ta）进行系统掺杂，随后改变电荷状态，我们探索了利用硅笼状团簇的电子封闭及其腔尺寸变化来促进金属原子封装。通过质谱、阴离子光电子能谱以及对H2O的吸附反应性获得的结果表明，掺杂4族原子的中性团簇在n = 16时具有电子封闭和几何封闭特性。掺杂4族原子的MSi(16)团簇在以下两种情况下会发生电子变化：(i) 当金属原子被3族或5族相邻金属原子取代时，价电子数量发生变化；(ii) 当用Zr和Hf的同组元素取代时，原子半径发生变化。卤素原子与MSi(16)团簇的反应性表明，VSi(16)F形成了具有离子键的超原子络合物。
