As part of our efforts toward the discovery of new late transition metal catalysts, we synthesized [(o-(Ph₂P)C₆H₄)₂(o-C₆Cl₄O₂)SbPh)Au]⁺ (3⁺) and [(o-(iPr₂P)C₆H₄)₂(o-C₆Cl₄O₂)SbPh)Au]⁺ (4⁺), two cationic bis(phosphino)gold stiborane complexes, which were isolated as their hexafluorophosphate salts and fully characterized. Structural and computational studies indicate that the cores of these two complexes are almost structurally and electronically identical. Despite these similarities, these two complexes exhibit different catalytic activities in the hydroamination of phenylacetylene using anilines or in the cyclization of N-(prop-2-yn-1-yl)benzamide. Indeed, whereas 3⁺ catalyzes both reactions, we found that 4⁺ is inactive. The data collected on these two complexes suggest that the origin of this contrasting behavior is steric, rather than electronic, with the relatively bulky iPr₂P ancillary ligands blocking access to the reactive gold center.

中文翻译：

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T型金→丁硼烷配合物作为嗜碳催化剂：外围取代基的影响。

作为我们发现新的晚期过渡金属催化剂的努力的一部分，我们合成了[（o-（Ph ₂ P）C ₆ H ₄）₂（o -C ₆ Cl ₄ O ₂）SbPh）Au] ⁺（3 ⁺）和[（o-（i Pr ₂ P）C ₆ H ₄）₂（o -C ₆ Cl ₄ O ₂）SbPh）Au] ⁺（4 ⁺），分离出两种阳离子双（膦基）金stiborane配合物，将其分离为六氟磷酸盐，并进行了充分表征。结构和计算研究表明，这两个复合物的核心在结构和电子方面几乎相同。尽管有这些相似性，这两种络合物在使用苯胺进行苯乙炔的加氢胺化或在N-（prop-2-yn-1-yl）苯甲酰胺的环化反应中表现出不同的催化活性。确实，尽管3 ⁺催化了两个反应，但我们发现4 ⁺没有活性。在这两个复合物中收集的数据表明，这种相对行为的起源是立体的，而不是电子的，而i Pr相对较大。₂ P辅助配体阻止进入反应性金中心。