Ahrens Alexander, Lustosa Danilo M, Karger Leonhard F P, Hoffmann Marvin, Rudolph Matthias, Dreuw Andreas, Hashmi A Stephen K
Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Im Neuenheimer Feld 205A, 69120 Heidelberg, Germany.
Dalton Trans. 2021 Jun 29;50(25):8752-8760. doi: 10.1039/d1dt01315g.
The reactivity of cationic (C^C)gold(iii) carbonyl complexes was investigated. While the in situ-formed IPrAu(bph)CO+ complex (bph = biphenyl-2,2'-diyl) does not undergo a migratory insertion of CO into the neighboring gold-carbon bond, nucleophiles can attack the coordinated CO moiety intermolecularly. Water as a nucleophile initiates a CO2 extrusion combined with a reductive C,H bond formation. The rapid formation of a gold(i) species from an intermediary gold(iii) carbonyl has not been observed before and shows a significant difference in reactivity between (C^C) and (C^N^C)gold(iii) carbonyls. The latter have been reported to form stable gold(iii) hydrides via the WGS reaction. In the case of methanol acting as a nucleophile attacking the gold(iii) carbonyl, no extrusion of CO2 is observed. Instead an intermediary gold(iii) carboxyl complex forms an aryl carboxylate via reductive C-C bond elimination. Experimental and theoretical studies on the mechanism explain the observed selectivities and give new insights into the reactivity of elusive gold(iii) carbonyls.
研究了阳离子（C^C）金（III）羰基配合物的反应活性。虽然原位形成的IPrAu（bph）CO⁺配合物（bph = 联苯-2,2'-二基）不会发生CO向相邻金-碳键的迁移插入，但亲核试剂可以分子间攻击配位的CO部分。作为亲核试剂的水引发了CO₂的挤出并伴随着还原性C-H键的形成。以前从未观察到中间体金（III）羰基快速形成金（I）物种，这表明（C^C）和（C^N^C）金（III）羰基在反应活性上存在显著差异。据报道，后者通过水煤气变换反应形成稳定的金（III）氢化物。在甲醇作为亲核试剂攻击金（III）羰基的情况下，未观察到CO₂的挤出。相反，中间体金（III）羧基配合物通过还原性C-C键消除形成芳基羧酸盐。对该机理的实验和理论研究解释了观察到的选择性，并为难以捉摸的金（III）羰基的反应活性提供了新的见解。
