Gorrell Ian B, Henderson Timothy W, Albdeery Kamal, Savage Philip M, Kee Terence P
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
Life (Basel). 2017 Nov 19;7(4):45. doi: 10.3390/life7040045.
It has been proposed that prebiotic chemical studies on the emergence of primitive life would be most relevant when performed in a hydrogel, rather than an aqueous, environment. In this paper we describe the ambient temperature coupling of phosphorus oxyacids [Pi] mediated by Fe(II) under aerobic conditions within a silica hydrogel (SHG) environment. We have chosen to examine SHGs as they have considerable geological precedence as key phases in silicification to rock formation. Following a description of the preparation and characterization studies on our SHG formulations, coupling experiments between Pi species are described across multiple permutations of (i) Pi compound; (ii) gel formulation; (iii) metal salt additive; and (iv) pH-modifying agent. The results suggest that successful Pi coupling, indicated by observation of pyrophosphate [PPi(V)] via P-NMR spectroscopy, takes place when the following components are present: (i) a mixture of mixture of Pi(III) and Pi(V) or pure PPi(III-V); (ii) Fe(II); (iii) acetic or formic acid (not hydrochloric acid); (iv) aerobic conditions or the presence of H₂O₂ as an oxidant; and (v) the presence of a gel system. On the basis of these, and aqueous control reactions, we suggest mechanistic possibilities.
有人提出，关于原始生命出现的益生元化学研究，在水凝胶而非水溶液环境中进行时最为相关。在本文中，我们描述了在二氧化硅水凝胶（SHG）环境中，有氧条件下由Fe(II)介导的含氧磷酸[Pi]的常温偶联。我们选择研究SHG，因为它们在硅化形成岩石的过程中作为关键阶段具有相当多的地质先例。在描述了我们的SHG配方的制备和表征研究之后，描述了在（i）Pi化合物；（ii）凝胶配方；（iii）金属盐添加剂；和（iv）pH调节剂的多种排列组合下Pi物种之间的偶联实验。结果表明，当存在以下成分时，通过P-NMR光谱观察到焦磷酸[PPi(V)]表明Pi成功偶联：（i）Pi(III)和Pi(V)的混合物或纯PPi(III-V)；（ii）Fe(II)；（iii）乙酸或甲酸（而非盐酸）；（iv）有氧条件或作为氧化剂的H₂O₂的存在；以及（v）凝胶系统的存在。基于这些以及水性对照反应，我们提出了可能的机理。
