Partial substitution of polyoxometalate (POM) is an efficient route to modulate the catalytic property of maternal POM. In this work, a new Keggin type POM involving {Ni₆} cluster, {[Ni(H₂O)₂(Dach)₂][Ni(Dach)₂]₂}{[Ni₆Cl(μ-OH)₃(H₂O)(Dach)₃(WO₄)(PW₉O₃₄)][Ni₆(μ-OH)₃(H₂O)₂(Dach)₃(WO₄)(PW₉O₃₄)]}Cl·27H₂O, (1, Dach = 1,2-diaminocyclohexane) was synthesized. Compounds 1 shows excellent catalytic performance in the selective oxidation of aniline to azoxybenzene (AOB) in water. The apparently different results from that with the matrix {PW₉O₃₄} ({PW₉}) suggest the successful regulation of the catalytic property of {PW₉} by the introduction of the {Ni₆} cluster into the skeleton. The experimental results indicate that the highlighted performance of 1 is contributed by the synergy of W and Ni sites, which are respectively responsible for the oxidation and condensation steps in the production of AOB. The good selectivity to AOB is essentially attributed to the effective modulation of the reaction rates of oxidation and condensation steps by W and Ni sites, respectively.

多金属氧酸盐 (POM) 的部分取代是调节母体 POM 催化性能的有效途径。在这项工作中，一种新的Keggin型POM涉及{Ni ₆ }簇，{[Ni(H ₂ O) ₂ (Dach) ₂ ][Ni(Dach) ₂ ] ₂ }{[Ni ₆ Cl( μ -OH) ₃ (H ₂ O)(Dach) ₃ (WO ₄ )(PW ₉ O ₃₄ )][Ni ₆ ( μ -OH) ₃ (H ₂ O) ₂ (Dach) ₃ (WO ₄ )(PW ₉ O ₃₄ )]合成了}Cl·27H ₂ O,( 1 ,Dach=1,2-二氨基环己烷)。化合物1在水中苯胺选择性氧化为氧化苯(AOB)方面表现出优异的催化性能。与基质{PW ₉ O ₃₄ } ({PW ₉ })明显不同的结果表明通过将{Ni ₆ }簇引入到骨架中成功调节了{PW ₉ }的催化性能。实验结果表明，1的突出性能是由W和Ni位点的协同作用贡献的，它们分别负责AOB生产中的氧化和缩合步骤。对 AOB 的良好选择性本质上归因于 W 和 Ni 位点分别对氧化和缩合步骤的反应速率的有效调节。