Alférez Macarena G, Moreno Juan J, Hidalgo Nereida, Campos Jesús
Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC), University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain.
Angew Chem Int Ed Engl. 2020 Nov 16;59(47):20863-20867. doi: 10.1002/anie.202008442. Epub 2020 Sep 9.
The use of cyclopentadienyl ligands in organometallic chemistry and catalysis is ubiquitous, mostly due to their robust spectator role. Nonetheless, increasing examples of non-innocent behaviour are being documented. Here, we provide evidence for reversible intramolecular C-H activation at one methyl terminus of CMe in [(η-CMe)Rh(PMe)] to form a new Rh-H bond, a process so far restricted to early transition metals. Experimental evidence was acquired from bimetallic rhodium/gold structures in which the gold center binds either to the rhodium atom or to the activated Cp* ring. Reversibility of the C-H activation event regenerates the Rh and Au monometallic precursors, whose cooperative reactivity towards polar E-H bonds (E=O, N), including the N-H bonds in ammonia, can be understood in terms of bimetallic frustration.
环戊二烯基配体在有机金属化学和催化中的应用十分广泛，这主要归功于它们强大的旁观作用。尽管如此，越来越多关于非无辜行为的例子被记录下来。在这里，我们提供了证据，证明在[(η-CMe)Rh(PMe)]中，CMe的一个甲基末端发生了可逆的分子内C-H活化，形成了一个新的Rh-H键，这一过程迄今为止仅限于早期过渡金属。实验证据来自双金属铑/金结构，其中金中心要么与铑原子结合，要么与活化的Cp*环结合。C-H活化事件的可逆性使Rh和Au单金属前体再生，它们对极性E-H键（E=O、N），包括氨中的N-H键的协同反应性，可以用双金属受挫来解释。
