Considered one of the most promising building blocks of life on primitive Earth, cyanide and its complexes are likely to have played an important role in the emergence of life on the planet. Investigation into cyanide on Earth has primarily considered high concentrations, but the cyanide concentration in the oceans of prebiotic Earth was exceptionally low. Thus, Bernal's hypothesis has allowed investigators to work around this problem. We observed, however, that cyanide does not adsorb onto several minerals; therefore, ferrocyanide could be used as a cyanide source when adsorbed onto mineral surfaces to promote the synthesis of molecules of biological significance. When adsorbed onto bentonite, a mineral that has Fe³⁺ atoms in its interlayers, the formation of Prussian blue analog complexes occurs through endothermic reaction and with increased entropy. The adsorption of ferrocyanide onto kaolinite indicates an exothermic and outer-sphere interaction, which results in degeneracy breakdown for C ≡ N stretch energy into two new bands of FTIR-ATR spectrum. Magnetite, which has iron atoms in its structure, and ferrocyanide interactions have been observed by outer-sphere coordination as well as the formation of Prussian blue analogs, as confirmed by the appearance of a new doublet in the Mössbauer spectra and a broadband close to 750 nm at UV-visible spectroscopy. Magnetite and kaolinite experiments presented relevant results only when performed in seawater, which suggests the importance of seawater composition for prebiotic experiments. These obtained results prove that ferrocyanide interacts with minerals differently according to structure and composition and show that this complex, like the Prussian blue analogs, may have played a crucial role as a source of cyanide on primitive Earth.

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不同矿物质对亚铁氰化物的吸附作为益生元化学分析的研究

氰化物及其复合物被认为是原始地球上最有希望的生命基石之一，很可能在地球上生命的出现中发挥了重要作用。对地球上氰化物的调查主要考虑了高浓度，但前生物地球海洋中的氰化物浓度异常低。因此，伯纳尔的假设使研究人员能够解决这个问题。然而，我们观察到氰化物不会吸附在几种矿物上。因此，亚铁氰化物在吸附到矿物表面时可用作氰化物来源，以促进具有生物学意义的分子的合成。当吸附在膨润土上时，膨润土是一种含有 Fe ^3+的矿物在其夹层原子中，普鲁士蓝类似物复合物的形成通过吸热反应和熵增加发生。亚铁氰化物在高岭石上的吸附表明放热和外层相互作用，这导致 C ≡ N 拉伸能量简并分解成两个新的 FTIR-ATR 谱带。通过外球配位以及普鲁士蓝类似物的形成观察到结构中具有铁原子的磁铁矿和亚铁氰化物相互作用，这已通过穆斯堡尔光谱中出现新的双峰和接近 750 的宽带得到证实纳米紫外可见光谱。磁铁矿和高岭石实验仅在海水中进行时才呈现相关结果，这表明海水成分对于益生元实验的重要性。