Pathway bias and emergence of quasi-irreversibility in reversible reaction networks: Extension of Curtin-Hammett principle

可逆な化学反応ネットワークにおける経路選択の原理 --準不可逆性の発現--. 京都大学プレスリリース. 2023-07-21.The Curtin-Hammett principle, which works in a reaction sequence where slow irreversible reactions are connected to a fast reversible reaction, determines the product distribution depending only on the relative energy barriers of the two irreversible reactions, resulting in kinetic pathway selection. A basic question is how the reaction pathway is selected in reaction networks composed of reversible reactions to generate a metastable state. Numerical simulations of model systems where reversible elementary reactions are connected linearly to an initial reversible reaction demonstrate that a metastable state far from equilibrium is transiently produced and that its lifetime is prolonged by increasing the number of connected reversible reactions. The pathway selection in the model systems originates from quasi-irreversibility, and a similar behavior was also observed in the molecular self-assembly of a Pd₆L₄ truncated tetrahedron, which supports the idea that the emergence of quasi-irreversibility is a key general concept underlining kinetic control in reversible reaction networks