Non-aqueous chromium acetylacetonate electrolyte for redox flow batteries

Non-aqueous manganese acetylacetonate electrolyte for redox flow batteries

Liquid-Assisted Grinding Mechanochemistry in the Synthesis of Pharmaceuticals

https://apps.dtic.mil/sti/pdfs/ADA094307.pdf

Entropic and enthalpic contributions to the solvent dependence of the thermodynamics of transition-metal redox couples

Transition metals in inorganic systems and metalloproteins can occur in different oxidation states, which makes them ideal redox-active catalysts To gain a mechanistic understanding of the catalytic reactions, knowledge of the oxidation state of the active metals, ideally in operando, is therefore critical L-edge X-ray absorption spectroscopy (XAS) is a powerful technique that is frequently used to infer the oxidation state via a distinct blue shift of L-edge absorption energies with increasing oxidation state A unified description accounting for quantum-chemical notions whereupon oxidation does not occur locally on the metal but on the whole molecule and the basic understanding that L-edge XAS probes the electronic structure locally at the metal has been missing to date Here we quantify how charge and spin densities change at the metal and throughout the molecule for both redox and core-excitation processes We explain the origin of the L-edge XAS shift between the high-spin complexes MnII(acac)2 and MnIII(acac)3 as representative model systems and use ab initio theory to uncouple effects of oxidation-state changes from geometric effects The shift reflects an increased electron affinity of MnIII in the core-excited states compared to the ground state due to a contraction of the Mn 3d shell upon core-excitation with accompanied changes in the classical Coulomb interactions This new picture quantifies how the metal-centered core hole probes changes in formal oxidation state and encloses and substantiates earlier explanations The approach is broadly applicable to mechanistic studies of redox-catalytic reactions in molecular systems where charge and spin localization/delocalization determine reaction pathways

/pdf/probing-the-oxidation-state-of-transition-metal-complexes-a-vpfa40qf6g.pdf

H. Murauer

Papers

The polarographic and voltammetric behaviour of acetylacetonato and hexafluoroacetylacetonato complexes in acetonitrile

Solvent and salt effects on the redox behaviour of trisacetylacetonato manganese(III)