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首页> 外文期刊>Chemistry: A European journal >Thermal Behavior of d-Ribose Adsorbed on Silica: Effect of Inorganic Salt Coadsorption and Significance for Prebiotic Chemistry
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Thermal Behavior of d-Ribose Adsorbed on Silica: Effect of Inorganic Salt Coadsorption and Significance for Prebiotic Chemistry

机译：d-核糖吸附在硅胶上的热行为：无机盐共吸附的影响及其对益生元化学的意义

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Understanding ribose reactivity is a crucial step in the RNA world scenario because this molecule is a component of all extant nucleotides that make up RNA. In solution, ribose is unstable and susceptible to thermal destruction. We examined how ribose behaves upon thermal activation when adsorbed on silica, either alone or with the coadsorption of inorganic salts (MgCl2, CaCl2, SrCl2, CuCl2, FeCl2, FeCl3, ZnCl2). A combination of (CNMR)-C-13, in situ IR, and TGA analyses revealed a variety of phenomena. When adsorbed alone, ribose remains stable up to 150 degrees C, at which point ring opening is observed, together with minor oxidation to a lactone. All the metal salts studied showed specific interactions with ribose after dehydration, resulting in the formation of polydentate metal ion complexes. Anomeric equilibria were affected, generally favoring ribofuranoses. Zn2+ stabilized ribose up to higher temperatures than bare silica (180 to 200 degrees C). Most other cations had an adverse effect on ribose stability, with ring opening already upon drying at 70 degrees C. In addition, alkaline earth cations catalyzed the dehydration of ribose to furfural and, to variable degrees, its further decarbonylation to furan. Transition-metal ions with open d-shells took part in redox reactions with ribose, either as reagents or as catalysts. These results allow the likelihood of prebiotic chemistry scenarios to be evaluated, and may also be of interest for the valorization of biomass-derived carbohydrates by heterogeneous catalysis.
机译：了解核糖反应性是RNA世界中至关重要的一步，因为该分子是构成RNA的所有现有核苷酸的组成部分。在溶液中，核糖不稳定并且容易受到热破坏。我们研究了核糖在单独或与无机盐（MgCl2，CaCl2，SrCl2，CuCl2，FeCl2，FeCl3，ZnCl2）共吸附时在热活化后在二氧化硅上的行为。 （CNMR）-C-13，原位红外和TGA分析的组合揭示了多种现象。当单独吸附时，核糖在高达150摄氏度的温度下仍保持稳定，这时观察到开环，同时轻微氧化为内酯。所研究的所有金属盐在脱水后均显示出与核糖的特定相互作用，从而形成了多齿金属离子络合物。端粒平衡受到影响，通常有利于呋喃核糖核酸酶。 Zn2 +稳定的核糖的温度要高于裸露的二氧化硅（180至200摄氏度）。大多数其他阳离子对核糖的稳定性有不利影响，在70摄氏度下干燥时已经开环。此外，碱土金属阳离子催化核糖脱水成糠醛，并在不同程度上催化其进一步脱羰成呋喃。带有开放d壳的过渡金属离子参与了与核糖的氧化还原反应，无论是作为试剂还是作为催化剂。这些结果使得可以评估益生元化学场景的可能性，并且对于通过异质催化对生物质衍生的碳水化合物进行增值评估也可能是有意义的。

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