Catalytic isomerization of 1-hexene to 2-hexene by halide clusters of Nb, Mo, Ta and W possessing an octahedral metal core
Catalytic isomerization of 1-hexene to 2-hexene by halide clusters of Nb, Mo, Ta and W possessing an octahedral metal core
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具有八面体金属核的 Nb、Mo、Ta、W 卤化物团簇催化 1-己烯异构化为 2-己烯
DOI：
10.1016/s1381-1169(02)00546-0
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发表时间：
2003
影响因子：
--
通讯作者：
T. Chihara
中科院分区：
文献类型：
--
作者：
S. Kamiguchi;M. Noda;Yuka Miyagishi;Satoru Nishida;M. Kodomari;T. Chihara
具有八面体金属骨架的卤化物团簇[(M6Cl12)Cl2(H2O)4]·4H2O （M: Nb, Ta）和（h30）2[(M6Cl8)Cl6]·6H2O （M: Mo， W）在高温氢流中处理时，对烯烃双键的异构化和轻微氢化具有催化活性。在Nb簇的情况下，高于200°C的处理产生催化活性。喇曼光谱表明，nb6的笼状呼吸运动保持不变，而[Nb6Cl12]的边缘桥接Nb-Cl的呼吸振动消失。以W簇为例，催化活性在300℃时出现，在该温度下[(W6Cl8)Cl4(H2O)2]结构开始衰变形成W6Cl12。450℃时，w6cl12的活性达到最大值，在此温度下，w6cl12的结构开始衰变。两个簇的元素分析表明Cl原子的损失。因此，这些团簇的激活发生在卤素配体的部分损失，使团簇框架完好无损。
Halide clusters, [(M6Cl12)Cl2(H2O)4]·4H2O (M: Nb, Ta) and (H3O)2[(M6Cl8)Cl6]·6H2O (M: Mo, W) with an octahedral metal framework, develop catalytic activity for the isomerization and slight hydrogenation of olefinic double bonds when the halide clusters are treated in a stream of hydrogen at elevated temperatures. In the case of Nb clusters, treatment above 200°C produces the catalytic activity. Raman spectra of such heat-treated clusters show that the cage breathing motion of Nb6remains intact, whereas the breathing vibrations of the edge bridging Nb–Cl of [Nb6Cl12] disappear. In the case of W clusters, the catalytic activity appears at 300°C, at which temperature the structure of [(W6Cl8)Cl4(H2O)2] begins to decay to form W6Cl12. Maximum activity emerges at 450°C, at which temperature the structure of W6Cl12begins to decay. Elemental analyses of both clusters show the loss of Cl atoms. Thus, activation of these clusters occurs by partial loss of the halogen ligands, leaving the cluster framework intact.