Jump to main content
Jump to site search

Issue 21, 2017
Previous Article Next Article

The open-cubane oxo–oxyl coupling mechanism dominates photosynthetic oxygen evolution: a comprehensive DFT investigation on O–O bond formation in the S4 state

Author affiliations

Abstract

The dioxygen formation mechanism of biological water oxidation in nature has long been the focus of argument; many diverse mechanistic hypotheses have been proposed. Based on a recent breakthrough in the resolution of the electronic and structural properties of the oxygen-evolving complex in the S3 state, our density functional theory (DFT) calculations reveal that the open-cubane oxo–oxyl coupling mechanism, whose substrates preferably originate from W2 and O5 in the S2 state, emerges as the best candidate for O–O bond formation in the S4 state. This is justified by the overwhelming energetic superiority of this mechanism over alternative mechanisms in both the isomeric open and closed-cubane forms of the Mn4CaO5 cluster; spin-dependent reactivity rooted in variable magnetic couplings was found to play an essential role. Importantly, this oxygen evolution mechanism is supported by the recent discovery of femtosecond X-ray free electron lasers (XFEL), and the origin of the observed structural changes from the S1 to S3 state has been analyzed. In this view, we corroborate the proposed water binding mechanism during S2–S3 transition and correlate the theoretical models with experimental findings from aspects of substrate selectivity according to water exchange kinetics. This theoretical consequence for native metalloenzymes may serve as a significant guide for improving the design and synthesis of biomimetic materials in the field of photocatalytic water splitting.

Graphical abstract: The open-cubane oxo–oxyl coupling mechanism dominates photosynthetic oxygen evolution: a comprehensive DFT investigation on O–O bond formation in the S4 state

Back to tab navigation

Supplementary files

Publication details

The article was received on 14 Mar 2017, accepted on 03 May 2017 and first published on 03 May 2017


Article type: Paper
DOI: 10.1039/C7CP01617D
Citation: Phys. Chem. Chem. Phys., 2017,19, 13909-13923
  •   Request permissions

    The open-cubane oxo–oxyl coupling mechanism dominates photosynthetic oxygen evolution: a comprehensive DFT investigation on O–O bond formation in the S4 state

    Y. Guo, H. Li, L. He, D. Zhao, L. Gong and Z. Yang, Phys. Chem. Chem. Phys., 2017, 19, 13909
    DOI: 10.1039/C7CP01617D

Search articles by author

Spotlight

Advertisements