Did Nature use Reduced Oxidation State Phosphorus in Prebiotic Chemistry? Strengthening the Case for a Non-Phosphate World prior to the RNA-World

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Phosphate is a key ingredient in all life on Earth. Phosphate is everywhere on Earth, we dig it out of the ground as a calcium salt, we use it to brush our teeth, we consume it in food and drink every day. However, despite it being a rather common chemical, it is by no means certain that Nature chose phosphate for the earliest forms of life on Earth. A large part of the problem is that phosphate chemicals are both extremely insoluble and very unreactive chemically. In 1955, the scientist Addison Gulick proposed that this phosphate problem could have been solved if other forms of phosphorus were available on the early Earth. These chemicals, called phosphonates and phosphinates, are close relatives of phosphate but are both more soluble and chemically reactive in water. The problem is that phosphonates and phosphinates are unknown on Earth today because over the millennia, the chemical environment of Earth has changed to such a degree that only phosphates are now stable. However, we have recently discovered that phosphinates and phosphonates could have been readily available to prebiotic chemistry on the early Earth through chemical reactions of iron-rich meteorites with water in the presence of light. This discovery allows us to explore in detail the potential of phosphonates and phosphinates in the origin-of-life problem for the first time with a degree of confidence that such chemistry could have been available on the early Earth.This project is built in two parts. In Part 1 we will look in detail at how exactly phosphonates and phosphinates were formed from the chemical modification of actual meteorite fragments. In Part 2, we explore potential chemical reactions which could have taken place on an early Earth with these two phosphorus species and which could have an impact in how some key biological molecules, such as prebiotic organic phosphorus polymers, might have emerged.