Comparison of mononuclear and dinuclear copper() biomimetic complexes: spectroelectrochemical mechanistic study of their catalytic pathways
Two catecholase-like biomimetic catalysts, namely, two dinuclear copper complexes [Cu 2 (L1)(OH)(H 2 O)(EtOH)][ClO 4 ] 2 ( C1 ) and [Cu 2 Ac 2 O(L1)ClO 4 ] ( C2 ) with the 2,6-bis(4-methyl piperazin-1-yl-methyl)-4-formyl-phenoxy ligand (L1) together with the mononuclear complex Cu(ClO 4 ) 2 (L2) ( C...
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Published in | Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 36; pp. 1373 - 13715 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
20.09.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | Two catecholase-like biomimetic catalysts, namely, two dinuclear copper complexes [Cu
2
(L1)(OH)(H
2
O)(EtOH)][ClO
4
]
2
(
C1
) and [Cu
2
Ac
2
O(L1)ClO
4
] (
C2
) with the 2,6-bis(4-methyl piperazin-1-yl-methyl)-4-formyl-phenoxy ligand (L1) together with the mononuclear complex Cu(ClO
4
)
2
(L2) (
C3
) containing ligand 1,2-(C
5
H
4
N-6-OCH
3
-2-CH&z.dbd;N)
2
CH
2
CH
2
(L2), were synthesized. Their catalytic pathways were investigated and compared. The evaluation of the catalytic activity of compound
C1
(and
C2
,
C3
) using the Michaelis-Menten model was represented by values of
K
M
= 272.93 (223.02; 1616) μmol L
−1
and
V
max
of 0.981 (1.617; 1.689) μmol L
−1
s
−1
. The role of water content in the solvent is also discussed. The dinuclear complexes
C1
and
C2
were found to be more efficient catalysts than mononuclear complex
C3
. The mode of catalytic action was characterized
via
cyclic voltammetry, spectrophotometry, and UV-Vis spectroelectrochemistry. The catalytic mechanism of 3,5-di-
tert
butyl catechol oxidation in the presence of oxygen was proposed. The reaction circle was proved by the confirmation of the chemical reversibility of complex reduction. The advantage of the
in situ
spectroelectrochemical measurement enabled to control the reduction of quinone formed by the chemical reaction of catechol with oxygen in solution. At this step, the simultaneous change in the absorption spectrum indicated a change in the copper redox state of the catalyst.
The catecholase-like biomimetic catalysts were proved for their catechol oxidation catalytic activity in the presence of oxygen and the catalytic mechanism was proposed using voltammetry,
in situ
UV-Vis spectroelectrochemistry and calculations. |
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Bibliography: | https://doi.org/10.1039/d2dt01610a Electronic supplementary information (ESI) available. See DOI ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1477-9226 1477-9234 |
DOI: | 10.1039/d2dt01610a |