Stephan Johannes, Bühler Raphael, Napoli Fabrizio E, Gemel Christian, Fischer Roland A
Chair of Inorganic and Metal-Organic Chemistry, Department of Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching, Germany.
Catalysis Research Center, Technical University of Munich, Ernst-Otto-Fischer-Straße 1, D-85748 Garching, Germany.
Inorg Chem. 2025 Aug 4;64(30):15707-15714. doi: 10.1021/acs.inorgchem.5c02296. Epub 2025 Jul 18.
Synergistic effects in mixed-metal complexes can lead to small-molecule activation and intriguing reactivity patterns. Herein, we report the dimerization of acetonitrile to a nacnac-type β-diketiminate ligand at the nickel/gallium complex fragment [Ni(GaCp*)] (Cp* = η-C(CH)). The coordination of GaCp* to the Ni(II) center leads to strong Lewis acidity at the initially Lewis basic Ga(I) ligand, which resembles an "umpolung" of the Ga center. The electrophilic Ga serves as the site of bond activation. DFT calculations indicate that the proximity of Ni and Ga and a Ga-rich coordination sphere around the Ni atom are essential for facilitating the reaction. Interestingly, we discovered an abnormally large kinetic isotope effect of 28 assigned to proton tunneling.
混合金属配合物中的协同效应可导致小分子活化和有趣的反应模式。在此，我们报道了乙腈在镍/镓配合物片段[Ni(GaCp*)]（Cp* = η-C(CH)）处二聚形成nacnac型β-二酮亚胺配体。GaCp*与Ni(II)中心的配位导致最初呈路易斯碱性的Ga(I)配体具有很强的路易斯酸性，这类似于Ga中心的“极性翻转”。亲电的Ga作为键活化位点。密度泛函理论计算表明，Ni和Ga的 proximity以及Ni原子周围富含Ga的配位球对于促进该反应至关重要。有趣的是，我们发现了一个归因于质子隧穿的异常大的动力学同位素效应，其值为28 。
