Homotopic sites in a well-controlled environment are not only ideal systems for mechanistic studies, but also allow optimal control of catalytic transformations. Sites having only a single metal cation and sites consisting of metal oxo complexes with few nickel (Ni) cations supported on the nodes of UiO-66 metal–organic framework (Ni-UiO-66) are studied for 1-butene dimerization. Monomeric Ni sites, which bind to the Zr₆ node via two Zr-OH(μ3) linkages, are active and selective for the dimerization of 1-butene to linear and mono-branched C₈ isomers. Ni oxo complexes with few Ni cations show lower activity and promote the oligomerization of transiently formed C8 isomers. Kohn-Sham density function theory calculations combined with spectroscopic measurements and kinetic analyses indicate that dimerization follows a Cossee-Arlman reaction mechanism.

控制良好的环境中的同伦位点不仅是机理研究的理想系统，而且还允许对催化转化进行最佳控制。研究了在 UiO-66 金属-有机骨架 (Ni-UiO-66) 节点上仅具有单一金属阳离子的位点和由具有少量镍 (Ni) 阳离子的金属氧代络合物组成的位点用于 1-丁烯二聚化。单体 Ni 位点通过两个 Zr-OH(μ3) 键与 Zr ₆节点结合，对 1-丁烯二聚成直链和单支链 C _{8具有活性和选择性}异构体。Ni 阳离子很少的 Ni 氧代络合物表现出较低的活性并促进瞬时形成的 C8 异构体的低聚。Kohn-Sham 密度函数理论计算结合光谱测量和动力学分析表明二聚化遵循 Cossee-Arlman 反应机制。