Abstract
With a view to developing multimetallic molecular catalysts that mimic the oxygen-evolving catalyst (OEC) in Nature's photosystem II, the synthesis of various dicubanoid manganese clusters is described and their catalytic activity investigated for water oxidation in basic, aqueous solution. Pyridinemethanol-based ligands are known to support polynuclear and cubanoid structures in manganese coordination chemistry. The chelators 2,6-pyridinedimethanol (H2L1) and 6-methyl-2-pyridinemethanol (HL2) were chosen to yield polynuclear manganese complexes;namely, the tetranuclear defective dicubanes [(Mn2Mn2III)-Mn-II(HL1)(4)(OAc)(4)(OMe)(2)] and [(Mn2Mn2III)-Mn-II(HL1)(6)(OAc)(2)] (OAc)(2).2 H2O, as well as the octanuclear-dicubanoid [(Mn6Mn2III)-Mn-II(L-2)(4)(O)(2)(OAc)(10)(HOMe/OH2)(2)].3MeOH.MeCN. In freshly prepared solutions, polynuclear species were detected by electrospray ionization mass spectrometry, whereas X-band electron paramagnetic resonance studies in dilute, liquid solution suggested the presence of divalent mononuclear Mn species with g values of 2. However, the magnetochemical investigation of the complexes' solutions by the Evans technique confirmed a haphazard combination of manganese coordination complexes, from mononuclear to polynuclear species. Subsequently, the newly synthesized and characterized manganese molecular complexes were employed as precursors to prepare electrode-deposited films in a buffer-free solution to evaluate and compare their stability and catalytic activity for water oxidation electrocatalysis.
Item Type: | Journal article |
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Faculties: | Chemistry and Pharmacy > Department of Chemistry |
Subjects: | 500 Science > 540 Chemistry |
ISSN: | 1864-5631 |
Language: | English |
Item ID: | 99081 |
Date Deposited: | 05. Jun 2023, 15:30 |
Last Modified: | 17. Oct 2023, 15:00 |