Spontaneous formation of autocatalytic sets with self-replicating inorganic metal oxide clusters

Abstract

Here we show how a simple inorganic salt can spontaneously form autocatalytic sets of replicating inorganic molecules that work via molecular recognition based on the {PMo₁₂} ≡ [PMo₁₂O₄₀]^3– Keggin ion, and {Mo₃₆} ≡ [H₃Mo₅₇M₆(NO)₆O₁₈₃(H₂O)₁₈]^22– cluster. These small clusters are able to catalyze their own formation via an autocatalytic network, which subsequently template the assembly of gigantic molybdenum-blue wheel {Mo₁₅₄} ≡ [Mo₁₅₄O₄₆₂H₁₄(H₂O)₇₀]^14–, {Mo₁₃₂} ≡ [Mo^VI₇₂Mo^V₆₀O₃₇₂(CH₃COO)₃₀(H₂O)₇₂]^42– ball-shaped species containing 154 and 132 molybdenum atoms, and a {PMo₁₂}⊂{Mo₁₂₄Ce₄} ≡ [H₁₆Mo^VI₁₀₀Mo^V₂₄Ce₄O₃₇₆(H₂O)₅₆ (PMo^VI₁₀Mo^V₂O₄₀)(C₆H₁₂N₂O₄S₂)₄]^5– nanostructure. Kinetic investigations revealed key traits of autocatalytic systems including molecular recognition and kinetic saturation. A stochastic model confirms the presence of an autocatalytic network involving molecular recognition and assembly processes, where the larger clusters are the only products stabilized by the cycle, isolated due to a critical transition in the network.