Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States.
J Am Chem Soc. 2015 Oct 21;137(41):13425-32. doi: 10.1021/jacs.5b07998. Epub 2015 Oct 12.
In search of new platforms that support redox-controlled catalysis, we have investigated the noninnocent behavior of chlorostibine ligands coordinated to gold. The gold chlorostibine complex ((o-(Ph2P)C6H4)2SbCl)AuCl (1-Cl) undergoes a clean oxidation reaction on treatment with PhICl2. This oxidation reaction affords the corresponding trichlorostiborane complex ((o-(Ph2P)C6H4)2SbCl3)AuCl (2-Cl), which can be converted into the more tractable trifluoride analogue ((o-(Ph2P)C6H4)2SbF3)AuCl (3-Cl) by treatment with a fluoride source. As supported by experimental and computational results, these complexes possess a Au→Sb donor-acceptor interaction which is distinctly stronger in the oxidized complexes 2-Cl and 3-Cl. Both 1-Cl and 3-Cl undergo a clean chloride abstraction reaction to afford the corresponding cationic gold species ((o-(Ph2P)C6H4)2SbCl)Au (1) and ((o-(Ph2P)C6H4)2SbF3)Au (3), which have been isolated as SbF6(-) salts. As a result of a stronger Au→Sb interaction, cation 3 features a more Lewis acidic gold center. It forms an isolable water adduct and also activates terminal alkynes toward hydroamination with arylamines. These results demonstrate that the redox state of noninnocent Z-ligands can be used to control the catalytic activity of the adjoining metal center.
在寻找支持氧化还原控制催化的新平台时，我们研究了与金配位的氯代膦配体的非中心行为。金氯代膦配合物((o-(Ph2P)C6H4)2SbCl)AuCl(1-Cl)在与 PhICl2 处理时发生干净的氧化反应。该氧化反应提供相应的三氯代硼酸酯配合物((o-(Ph2P)C6H4)2SbCl3)AuCl(2-Cl)，其可通过用氟源处理转化为更易处理的三氟化物类似物((o-(Ph2P)C6H4)2SbF3)AuCl(3-Cl)。实验和计算结果表明，这些配合物具有 Au→Sb 供体-受体相互作用，在氧化配合物 2-Cl 和 3-Cl 中明显更强。1-Cl 和 3-Cl 都经历了干净的氯化物抽提反应，得到相应的阳离子金物种((o-(Ph2P)C6H4)2SbCl)Au(1)和((o-(Ph2P)C6H4)2SbF3)Au(3)，它们已被分离为 SbF6(-)盐。由于更强的 Au→Sb 相互作用，阳离子3具有更路易斯酸性的金中心。它形成可分离的水加合物，并可激活末端炔烃进行芳胺的氨化反应。这些结果表明，非中心 Z-配体的氧化还原状态可用于控制相邻金属中心的催化活性。
