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Mikata Y, Uchida M, Koike H, Shoji S, Ohsedo Y, Kawai Y, Matsuo T. Evaluation of oxygen-containing pentadentate ligands with pyridine/quinoline/isoquinoline binding sites via the structural and electrochemical properties of mononuclear copper(II) complexes. Dalton Trans 2023; 52:17375-17388. [PMID: 37941474 DOI: 10.1039/d3dt02814c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Eighteen mononuclear copper(II) complexes with oxygen-containing N4O1 pentadentate ligands were prepared. The ligand library consists of 2-aminoethanol derivatives ((Ar1CH2)(Ar2CH2)NCH2CH2OCH2Ar3) bearing three nitrogen-containing heteroaromatics (Ars) including pyridine, quinoline and isoquinoline via a methylene linker. Systematic replacements of pyridine binding sites with quinolines and isoquinolines reveal the general trends in the perturbation of bond distances and angles, the redox potential and the absorption maximum wavelength of the copper(II) complexes, depending on the position and number of (iso)quinoline heteroaromatics. The small effect on the redox potentials resulting from quinoline substitution at the Ar3 position (near oxygen) of the ligand comes from the steric hindrance of the peri hydrogen atom in the quinoline moiety at this position, which removes the counter anion to enhance the coordination of quinoline nitrogen and ether oxygen atoms to the metal centre. In the absorption spectra of copper(II) complexes in the d-d transition region, the quinoline substitution at this site (Ar3) exhibits an opposite effect to those at the Ar1 and Ar2 sites. The electronic and steric contributions of the heteroaromatic binding sites to the ligand properties are comprehensively discussed.
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Affiliation(s)
- Yuji Mikata
- Laboratory for Molecular & Functional Design, Department of Engineering, Nara Women's University, Nara 630-8506, Japan.
- KYOUSEI Science Center, Nara Women's University, Nara 630-8506, Japan
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Mizuho Uchida
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Hinata Koike
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Sunao Shoji
- Laboratory for Molecular & Functional Design, Department of Engineering, Nara Women's University, Nara 630-8506, Japan.
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Yutaka Ohsedo
- Laboratory for Molecular & Functional Design, Department of Engineering, Nara Women's University, Nara 630-8506, Japan.
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Yasushi Kawai
- Nagahama Institute of Bio-Science & Technology, Nagahama, Shiga 526-0829, Japan
| | - Takashi Matsuo
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), Takayama, Ikoma, Nara 630-0192, Japan
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Mikata Y, Aono Y, Yamamoto C, Nakayama H, Matsumoto A, Kotegawa F, Harada M, Katano H, Kobayashi Y, Yanagisawa S, Kubo M, Kajiwara A, Kodera M. A Synthetic Model for the Possible Fe IV2(μ-O) 2 Core of Methane Monooxygenase Intermediate Q Derived from a Structurally Characterized Fe IIIFe IV(μ-O) 2 Complex. Inorg Chem 2022; 61:786-790. [PMID: 34822245 DOI: 10.1021/acs.inorgchem.1c02699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A bis(μ-oxo)diiron(IV,IV) complex as a model for intermediate Q in the methane monooxygenase reaction cycle has been prepared. The precursor complex with a [FeIIIFeIV(μ-O)2] core was fully characterized by X-ray crystallography and other spectroscopic analyses and was converted to the [FeIV2(μ-O)2] complex via electrochemical oxidation at 1000 mV (vs Ag/Ag+) in acetone at 193 K. The UV-vis spectral features, Mössbauer parameters (ΔEQ = 2.079 mm/s and δ = -0.027 mm/s), and EXAFS analysis (Fe-O/N = 1.73/1.96 Å and Fe···Fe = 2.76 Å) support the structure of the low-spin (S = 1, for each Fe) [FeIV2(μ-O)2] core. The rate constants of the hydrogen abstraction reaction from 9,10-dihydroanthracene at 243 K suggest the high reactivity of these synthetic bis(μ-oxo)diiron complexes supported by simple N4 tripodal ligand.
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Affiliation(s)
- Yuji Mikata
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
- KYOUSEI Science Center, Nara Women's University, Nara 630-8506, Japan
| | - Yuri Aono
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Chihiro Yamamoto
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Hiromi Nakayama
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Arimasa Matsumoto
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Fukue Kotegawa
- Department of Computer Science and Clothing Environment, Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan
| | - Masafumi Harada
- Department of Computer Science and Clothing Environment, Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan
| | - Hajime Katano
- Department of Bioscience, Fukui Prefectural University, Eiheiji, Fukui 910-1195, Japan
| | - Yoshio Kobayashi
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
| | - Sachiko Yanagisawa
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Atsushi Kajiwara
- Department of Materials Science, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
| | - Masahito Kodera
- Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe, Kyoto 610-0321, Japan
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Thermally stable manganese(III) peroxido complexes with hindered N3 tripodal ligands: Structures and their physicochemical properties. J Inorg Biochem 2021; 225:111597. [PMID: 34547605 PMCID: PMC10019377 DOI: 10.1016/j.jinorgbio.2021.111597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/25/2021] [Accepted: 08/28/2021] [Indexed: 11/20/2022]
Abstract
Mononuclear manganese(III) peroxido complexes are candidates for the reaction intermediates in manganese containing proteins, such as manganese superoxide dismutase (Mn-SOD) etc. In this study, manganese(III) peroxido complexes [Mn(O2)(L3)] and [Mn(O2)(L10)] ligated by anionic N3 type ligands with sterically hindered substituents, hydrotris(3-tertiary butyl-5-isopropyl-1-pyrazolyl)borate (L3-) and hydrotris(3-adamantyl-5-isopropyl-1-pyrazolyl)borate (L10-), respectively, were structurally characterized. These complexes are the first examples of structurally characterized five-coordinate manganese(III) peroxido complexes. Their characteristic ν(OO) and ν(MnO) stretchings were determined by using H218O2 for the first time. Theoretical calculations were performed to obtain further insight into their structural parameters. The decomposed products were obtained as [{MnIII(μ-O)(L3)}2MnIV] and [MnIII(OH){L10(O)}] from [Mn(O2)(L3)] and [Mn(O2)(L10)], respectively.
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