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Title: Assembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn sub 3 O sub 4 sup 4+ and Mn sub 2 O sub 2 sup 3+ complexes

Abstract

The aqueous chemistry of a binuclear mixed-valence cluster, ((bpy){sub 2}Mn(O){sub 2}Mn(bpy){sub 2})(ClO{sub 4}){sub 3} (1), has been investigated. The cluster exists in a pH-dependent equilibrium with a higher valent trinuclear species, (Mn{sub 3}O{sub 4}(bpy){sub 4}(OH{sub 2}){sub 2}){sup 4+} (2). The trinuclear cluster is favored at low pH, conditions that favor disproportionation of 1. Evaporation of a pH 1.9 solution of 1 leads to the precipitation of red crystals of 2 in the space group P{bar 1} with a = 14.902 (5) {angstrom}, b = 15.787 (5) {angstrom}, c = 12.676 (4) {angstrom}, {alpha} = 100.22 (2){degree}, {beta} = 93.45 (3){degree}, and {gamma} = 73.98 (3){degree}. The temperature-dependent magnetic susceptibility shows strong antiferromagnetic coupling. Electrochemistry and EPR show that the concentrations of 1 and 2 are governed by a pH-dependent equilibrium. The relevance of this quantitative equilibrium to the photoactivated assembly of the manganese tetramer in photosystem II is discussed.

Authors:
; ; ; ;  [1]
  1. Yale Univ., New Haven, CT (USA)
Publication Date:
OSTI Identifier:
5494400
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society; (United States)
Additional Journal Information:
Journal Volume: 112:20; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MANGANESE COMPOUNDS; CRYSTAL STRUCTURE; MAGNETIC SUSCEPTIBILITY; AQUEOUS SOLUTIONS; CHEMICAL PREPARATION; PH VALUE; PHOTOSYNTHESIS; TEMPERATURE DEPENDENCE; CHEMICAL REACTIONS; DISPERSIONS; MAGNETIC PROPERTIES; MIXTURES; PHOTOCHEMICAL REACTIONS; PHYSICAL PROPERTIES; SOLUTIONS; SYNTHESIS; TRANSITION ELEMENT COMPOUNDS; 140505* - Solar Energy Conversion- Photochemical, Photobiological, & Thermochemical Conversion- (1980-); 400500 - Photochemistry

Citation Formats

Sarneski, J E, Thorp, H H, Brudvig, G W, Crabtree, R H, and Schulte, G K. Assembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn sub 3 O sub 4 sup 4+ and Mn sub 2 O sub 2 sup 3+ complexes. United States: N. p., 1990. Web. doi:10.1021/ja00176a027.
Sarneski, J E, Thorp, H H, Brudvig, G W, Crabtree, R H, & Schulte, G K. Assembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn sub 3 O sub 4 sup 4+ and Mn sub 2 O sub 2 sup 3+ complexes. United States. https://doi.org/10.1021/ja00176a027
Sarneski, J E, Thorp, H H, Brudvig, G W, Crabtree, R H, and Schulte, G K. 1990. "Assembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn sub 3 O sub 4 sup 4+ and Mn sub 2 O sub 2 sup 3+ complexes". United States. https://doi.org/10.1021/ja00176a027.
@article{osti_5494400,
title = {Assembly of high-valent oxomanganese clusters in aqueous solution. Redox equilibrium of water-stable Mn sub 3 O sub 4 sup 4+ and Mn sub 2 O sub 2 sup 3+ complexes},
author = {Sarneski, J E and Thorp, H H and Brudvig, G W and Crabtree, R H and Schulte, G K},
abstractNote = {The aqueous chemistry of a binuclear mixed-valence cluster, ((bpy){sub 2}Mn(O){sub 2}Mn(bpy){sub 2})(ClO{sub 4}){sub 3} (1), has been investigated. The cluster exists in a pH-dependent equilibrium with a higher valent trinuclear species, (Mn{sub 3}O{sub 4}(bpy){sub 4}(OH{sub 2}){sub 2}){sup 4+} (2). The trinuclear cluster is favored at low pH, conditions that favor disproportionation of 1. Evaporation of a pH 1.9 solution of 1 leads to the precipitation of red crystals of 2 in the space group P{bar 1} with a = 14.902 (5) {angstrom}, b = 15.787 (5) {angstrom}, c = 12.676 (4) {angstrom}, {alpha} = 100.22 (2){degree}, {beta} = 93.45 (3){degree}, and {gamma} = 73.98 (3){degree}. The temperature-dependent magnetic susceptibility shows strong antiferromagnetic coupling. Electrochemistry and EPR show that the concentrations of 1 and 2 are governed by a pH-dependent equilibrium. The relevance of this quantitative equilibrium to the photoactivated assembly of the manganese tetramer in photosystem II is discussed.},
doi = {10.1021/ja00176a027},
url = {https://www.osti.gov/biblio/5494400}, journal = {Journal of the American Chemical Society; (United States)},
issn = {0002-7863},
number = ,
volume = 112:20,
place = {United States},
year = {Wed Sep 26 00:00:00 EDT 1990},
month = {Wed Sep 26 00:00:00 EDT 1990}
}