We theoretically propose a photoinduced water-splitting cycle catalyzed by a binuclear Mn oxo complex. In our "bottom-up approach" to this problem, we once proposed a working minimal model of water-splitting cycle in terms of a mononuclear Mn oxo complex as a catalyst along with water clusters [K. Yamamoto and K. Takatsuka, Phys. Chem. Chem. Phys. 20, 6708 (2018)]. However, this catalyst is not self-contained in that the cycle additionally needs buffering molecules for electrons and protons in order to reload the Mn complex with electrons and protons, which are lost by photoinduced charge separation processes. We here show that a binuclear Mn oxo complex works as a self-contained photocatalyst without further assistant of additional reagents and propose another catalytic cycle in terms of this photocatalyst. Besides charge separation and proton relay transfer, the proposed cycle consists of other fundamental chemical dynamics including electron-proton reloading, radical relay-transfer, and Mn reduction. The feasibility of the present water-splitting cycle is examined by means of full dimensional nonadiabatic electron-wavepacket dynamics based on multireference electronic wavefunctions and energy profiles estimated with rather accurate quantum chemical methods for all the metastable states appearing in the cycle.

中文翻译：

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双核锰氧基络合物作为水分解循环中的自包含光催化剂：额外的锰氧化物作为电子和质子的缓冲剂的作用。

我们从理论上提出了双核锰氧配合物催化的光致水分解循环。在我们针对此问题的“自下而上的方法”中，我们曾经提出了一个有效的水分解周期最小模型，该模型以单核锰氧配合物作为催化剂以及水团簇[K. Yamamoto和K. Takatsuka，物理学 化学 化学 物理 20，6708（2018）]。然而，该催化剂不是自成一体的，因为该循环另外需要用于电子和质子的缓冲分子，以便用电子和质子重载Mn络合物，所述电子和质子由于光诱导的电荷分离过程而丢失。我们在这里表明，双核Mn羰基配合物可以作为自包含的光催化剂而无需其他试剂的进一步辅助，并且就该光催化剂提出了另一种催化循环。除了电荷分离和质子中继转移，拟议的循环还包括其他基本化学动力学，包括电子质子重载，自由基中继转移和Mn还原。通过基于多参考电子波函数和能量分布的全尺寸非绝热电子波动力学，用相当精确的量子化学方法对循环中出现的所有亚稳态进行了估算，从而检验了本次水分解循环的可行性。