Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
ACTI, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
Inorg Chem. 2023 Jan 30;62(4):1708-1718. doi: 10.1021/acs.inorgchem.2c04166. Epub 2023 Jan 19.
The reactions leading to the formation of C-heteroatom bonds in the coordination sphere of Au(III) complexes are uncommon, and their mechanisms are not well known. This work reports on the synthesis and reductive elimination reactions of a series of Au(III) methyl complexes containing different Au-heteroatom bonds. Complexes [Au(CF)(Me)(X)(PR)] (R = Ph, X = OTf, OClO, ONO, OC(O)CF, F, Cl, Br; R = Cy, X = Me, OTf, Br) were obtained by the reaction of -[Au(CF)(Me)(PR)] (R = Ph, Cy) with HX. The cationic complex -[Au(CF)(Me)(PPh)]OTf was obtained by the reaction of [Au(CF)(Me)(OTf)(PPh)] with PPh. Heating these complexes led to the reductive elimination of MeX (X = Me, PhP, OTf, OClO, ONO, OC(O)CF, F, Cl, Br). Mechanistic studies indicate that these reductive elimination reactions occur either through (a) the formation of tricoordinate intermediates by phosphine dissociation, followed by reductive elimination of MeX, or (b) the attack of weakly coordinating anionic (TfO or ClO) or neutral nucleophiles (PPh or NEt) to the Au-bound methyl carbon. The obtained results show for the first time that the nucleophilic substitution should be considered as a likely reductive elimination pathway in Au(III) alkyl complexes.
在 Au(III) 配合物的配位球中形成 C-杂原子键的反应并不常见，其机制也不为人知。本工作报道了一系列含有不同 Au-杂原子键的 Au(III) 甲基配合物的合成及还原消除反应。通过 -[Au(CF)(Me)(PR)]（R = Ph，Cy）与 HX 的反应得到了配合物 [Au(CF)(Me)(X)(PR)]（R = Ph，X = OTf，OClO，ONO，OC(O)CF，F，Cl，Br；R = Cy，X = Me，OTf，Br）。通过 [Au(CF)(Me)(OTf)(PPh)] 与 PPh 的反应得到了阳离子配合物 -[Au(CF)(Me)(PPh)]OTf。加热这些配合物导致 MeX（X = Me，PhP，OTf，OClO，ONO，OC(O)CF，F，Cl，Br）的还原消除。机理研究表明，这些还原消除反应通过（a）膦配体的解离形成三配位中间体，然后进行 MeX 的还原消除，或者（b）弱配位阴离子（TfO 或 ClO）或中性亲核试剂（PPh 或 NEt）进攻 Au 键合的甲基碳来发生。所得结果首次表明，亲核取代反应应被视为 Au(III) 烷基配合物中可能的还原消除途径。
