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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Solid state CP/MAS ~(13)C NMR of the insoluble organic matter of the Orgueil and Murchison meteorites: quantitative study
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Solid state CP/MAS ~(13)C NMR of the insoluble organic matter of the Orgueil and Murchison meteorites: quantitative study

机译：Orgueil和Murchison陨石的不溶有机物的固态CP / MAS〜（13）C NMR：定量研究

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摘要

Solid state CP/MAS ~(13)C nuclear magnetic resonance (NMR) study of the insoluble organic fraction isolated by HF/HCl treatment under an inert atmosphere from the Orgueil and Murchison carbonaceous meteorites is reported. Based on these spectra, eight different types of carbons (aro- and ali-linked CH_3, CH_2, aliphatic C-linked to heteroelements, protonated and non-protonated aromatic C, carboxyls and carbonyls) were identified, their relative amounts were determined and theoretical NMR-derived H/C atomic ratios were calculated. Comparison of these H/C ratios with those obtained from elemental analysis revealed that a large part of the carbons of the insoluble fraction of both meteorites are not detected by CP/MAS ~(13)C NMR. Taking into account these undetected carbons, the relative abundance of aromatic carbons (as % of the total carbons) was calculated as between 69 and 78% in Orgueil and 61 and 67% in Murchison and thus shown to be much higher than previously thought. In addition, the NMR data allowed to calculate the ratio of non-protonated and protonated aromatic carbons. Based on previous studies on chemical and thermal degradation, the present NMR data were interpreted as reflecting the occurrence of highly substituted rather small aromatic moieties in these insoluble organic materials. Along with FTIR data, NMR results also pointed to a relatively high branching level in the aliphatic chains, especially for Murchison. According to the above results, the insoluble organic matter in these meteorites did not suffer a marked thermal maturation during the late hydrothermalism of the parent body. Its synthesis involved a statistical combination of all the possible bonds between 0-CH_3, -CH_2 and -CH radicals, producing both the aliphatic and the aromatic moieties. This model explains not only the chemical features of the chondritic insoluble organic material but also the typical FTIR signature of the interstellar medium. Therefore, organic material found in the interstellar medium and that incorporated in the most primitive objects of the solar system seem to share a common organosynthesis.
机译：据报道，在惰性气氛下，由Orgueil和Murchison碳质陨石通过HF / HCl处理分离出的不溶有机物，进行了固态CP / MAS〜（13）C核磁共振（NMR）研究。根据这些光谱，鉴定了八种不同类型的碳（芳族和脂族连接的CH_3，CH_2，与杂元素连接的脂族C，质子化和非质子化的芳族C，羧基和羰基碳），确定了它们的相对量并从理论上计算了NMR衍生的H / C原子比。将这些H / C比与通过元素分析获得的H / C比进行比较后发现，CP / MAS〜（13）C NMR并未检测到两种陨石的不溶部分的大部分碳。考虑到这些未检测到的碳，计算出的芳族碳的相对丰度（占总碳的百分比）在Orgueil中为69％至78％，在Murchison中为61％至67％，因此比以前认为的要高得多。另外，NMR数据允许计算非质子化和质子化的芳族碳的比例。基于对化学和热降解的先前研究，当前的NMR数据被解释为反映了这些不溶有机材料中高度取代的相当小的芳族部分的出现。连同FTIR数据一样，NMR结果也表明脂肪族链中的支链水平较高，特别是对于Murchison。根据上述结果，这些陨石中的不溶性有机物在母体晚期热液化过程中并未经历明显的热成熟。它的合成涉及0-CH_3，-CH_2和-CH自由基之间所有可能键的统计组合，同时产生脂族和芳族部分。该模型不仅解释了软骨不溶性有机物质的化学特征，还解释了星际介质的典型FTIR标记。因此，星际介质中发现的有机物质和太阳系最原始物体中所包含的有机物质似乎具有共同的有机合成。

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