Copper(I)−Olefin Complexes: The Effect of the Trispyrazolylborate Ancillary Ligand in Structure and Reactivity

The spectroscopic and structural characteristics and the relative reactivity of several TpMsCu(olefin) (olefin = ethylene, 1, 1-hexene, 2, allyl ethyl ether, aee, 3, cyclohexene, 4, and styrene, 5) complexes bearing the bulky hydrotris(3-mesitylpyrazolyl)borate ligand have been examined. Experimental data, including an unusual high-field chemical shift in the 1H and 13C NMR spectra, and DFT theoretical calculations support the proposal that the copper−olefin linkage is mainly sustained by σ-donation, lacking a substantial degree of π-back-donation.

本研究考察了一系列带有大位阻氢三(3-均三甲苯基吡唑基)硼酸盐配体的TpMsCu(烯烃)配合物（其中烯烃配体分别为乙烯（1）、1-己烯（2）、烯丙基乙基醚（aee，3）、环己烯（4）以及苯乙烯（5））的光谱与结构特征，以及其相对反应活性。实验数据，包括1H与13C核磁共振谱中观测到的反常高场化学位移，结合密度泛函理论（Density Functional Theory，DFT）计算结果，均支持该铜-烯烃键主要通过σ配位作用维系、且不具备显著π反馈配位程度的结论。