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Modeling the OEC with Two New Biomimetic Models: Preparations, Structural Characterization, and Water Photolysis Studies of a Ba--Mn Box Type Complex and a Mn4N6 Planar-Diamond Cluster.
- Source :
- Catalysts (2073-4344); Sep2018, Vol. 8 Issue 9, p382, 17p
- Publication Year :
- 2018
-
Abstract
- The oxygen-evolving complex (OEC) is the native enzyme that catalyzes the oxidation of water in natural photosynthesis. Two new classes of manganese cluster complexes of formula Ba<subscript>2</subscript>Mn<subscript>2</subscript>L¹<subscript>2</subscript>(H<subscript>3</subscript>L¹)<subscript>2</subscript>(CH<subscript>3</subscript>OH)<subscript>4</subscript>1 and Mn<subscript>4</subscript>L²<subscript>6</subscript>Cl<subscript>2</subscript> 2 were prepared (H4L¹ = N,N0-(ethane-1,2-diyl)bis (2-hydroxybenzamide); L² = methyl picolinimidate) and characterized by standard techniques including microanalysis, IR spectroscopy, ESI spectrometry, and magnetic susceptibility measurements. X-ray diffraction studies of these complexes revealed (i) a box-type structure for 1 formed by two redox-active manganese(III) ions and two barium(II) ions connected by two bridging bisamido-bisphenoxy ligand molecules; and (ii) a planar-diamond array for Mn<subscript>4</subscript>N<subscript>6</subscript> cluster 2 where the picolinimidates act as chelating ligands through the two nitrogen atoms. The ability of 1 and 2 to split water has been studied by means of water photolysis experiments. In these experiments, the oxygen evolution was measured in aqueous media in the presence of p-benzoquinone (acting as the hydrogen acceptor), the reduction of which was followed by UV-spectroscopy. The relevant photolytic activity found for 1 is in contrast to the inactivity of 2 in the photolytic experiments. This different behavior is discussed on the basis of the structure of the biomimetic models and the proposed reaction mechanism for this process supported by DFT calculations. [ABSTRACT FROM AUTHOR]
- Subjects :
- BIOMIMETIC chemicals
ARTIFICIAL photosynthesis
PHOTOCATALYSTS
Subjects
Details
- Language :
- English
- ISSN :
- 20734344
- Volume :
- 8
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Catalysts (2073-4344)
- Publication Type :
- Academic Journal
- Accession number :
- 131972286
- Full Text :
- https://doi.org/10.3390/catal8090382