Effect of Copper Salts on Amide Hydrothermal Formation and Reactivity
Effect of Copper Salts on Amide Hydrothermal Formation and Reactivity
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DOI：
10.1021/acsearthspacechem.0c00150
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发表时间：
2020-09-17
影响因子：
3.4
通讯作者：
Yang, Ziming
中科院分区：
文献类型：
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作者：
Fu, Xuan;Liao, Yiju;Yang, Ziming
与环境条件不同，高温高压下的水可以越来越有利于疏水性有机分子的溶解，充当酸/碱催化剂，并引发独特的水热途径。在最近的一项研究中，我们发现，在水热溶液中，可以很容易地从简单的胺和羧酸合成酰胺，这意味着在天然水热环境中的潜在的肽和生物分子的合成途径。酰胺键或肽键的形成对于在热液系统中产生肽和蛋白质的结构单元是至关重要的，肽和蛋白质是活生物体（例如极端微生物）所必需的。然而，在水热条件下酰胺的形成和降解途径仍然没有得到很好的理解，特别是这些途径如何受到周围矿物质或溶解金属的影响是未知的。在这里，我们描述了铜（II）盐，如氯化铜和硫酸铜，在250摄氏度和40巴（P-sat）下对酰胺的水热形成和反应性的影响。选择铜盐进行研究是因为它们通常分布在海水和热液流体中。我们发现铜盐极大地抑制了酰胺的形成，酰胺产率在2 h内降低高达90%。我们还观察到，通过铜氧化胺，醛迅速形成，并成为主导产品。与氯化铜/硫酸铜相比，乙酸铜也促进了胺的氧化，但不抑制酰胺的形成，这表明铜盐在酰胺水热合成中的不同作用。此外，我们发现酰胺的水热反应性强烈依赖于溶液的pH值，在中性pH值下的反应性低于在非常酸性或碱性的条件下。因此，我们的研究结果表明，铜和pH值是重要的因素，酰胺水热合成和反应性，这提供了新的见解预测在天然水热环境中的酰胺或肽键的合成。
Unlike ambient conditions, water at elevated temperature and pressure can increasingly favor dissolution of hydrophobic organic molecules, act as an acid/base catalyst, and trigger unique hydrothermal pathways. In a recent study, we found that amides could be readily synthesized from simple amines and carboxylic acids in hydrothermal solutions, which implied a potential peptide and biomolecule synthetic pathway in natural hydrothermal environments. Formation of amide or peptide bonds is critical in producing building blocks of peptides and proteins, which are essential to living organisms, such as extremophiles, in hydrothermal systems. However, amide formation and degradation pathways under hydrothermal conditions are still not well understood, particularly how these pathways would be influenced by surrounding minerals or dissolved metals is unknown. Here, we describe the effects of copper(II) salts, such as copper chloride and copper sulfate, on the hydrothermal formation and reactivity of amides at 250 degrees C and 40 bar (P-sat). The copper salts were chosen to be studied because they are commonly distributed in seawater and hydrothermal fluids. We found that the copper salts greatly inhibited the amide formation, with a decreased amide yield by up to 90% within 2 h. We also observed that aldehydes were quickly formed through the oxidation of amines by copper and became the dominant products. Compared to copper chloride/sulfate, copper acetate also facilitated the amine oxidation but did not suppress the amide formation, suggesting different roles of copper salts in amide hydrothermal synthesis. In addition, we found that hydrothermal reactivity of amides was strongly dependent on the solution pH, with lower reactivity at neutral pH than at very acidic or alkaline conditions. Our findings thus suggest that both copper and pH are important factors for amide hydrothermal synthesis and reactivity, which provide new insights into the prediction of amide or peptide bond synthesis in natural hydrothermal environments.