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Yan H, Wu B, Wei J, Zhang WX. Insight into the Ligand-to-Ligand Charge-Transfer Process in Rare-Earth-Metal Diradical Complexes. Inorg Chem 2023; 62:8052-8057. [PMID: 37184543 DOI: 10.1021/acs.inorgchem.3c00900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
While a ligand-to-ligand charge-transfer (LLCT) process is an important way to understand the interactions between metal-bridged radicals for late-transition-metal complexes, there is little clear and evident observation of the LLCT process for rare-earth-metal complexes. In this work, rare-earth-metal diradical complexes supported by diazabutadiene (DAD) ligands [(DAD)2RE(BH4)] [RE = Yb (1), Sm (2)] were synthesized and studied. The coordination geometries of 1 and 2 are different due to the different ionic radii. Reduction of 1 or 2 generated monoradical complexes, with one of their DAD radical anions being reduced. In all of the complexes, Sm and Yb remain at the 3+ valence state. In their UV-vis spectra, the LLCT transition of 1 could be clearly observed, but complex 2 did not show the same transition. These results could be related to the geometric structures of the complexes as well as exchange coupling between diradicals, thus clearly expanding the model for late-transition-metal-bridged diradicals to rare-earth systems experimentally.
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Affiliation(s)
- Haihan Yan
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Botao Wu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Junnian Wei
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wen-Xiong Zhang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare-earth Materials Chemistry and Applications, and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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2
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Affiliation(s)
- Milica Feldt
- Leibniz Institute for Catalysis: Leibniz-Institut fur Katalyse eV Theory & Catalysis Albert-Einstein-Str 29A 18059 Rostock GERMANY
| | - Quan Manh Phung
- Nagoya University: Nagoya Daigaku Department of Chemistry JAPAN
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3
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Wang P, Killian MM, Saber MR, Qiu T, Yap GPA, Popescu CV, Rosenthal J, Dunbar KR, Brunold TC, Riordan CG. Electronic, Magnetic, and Redox Properties and O 2 Reactivity of Iron(II) and Nickel(II) o-Semiquinonate Complexes of a Tris(thioether) Ligand: Uncovering the Intradiol Cleaving Reactivity of an Iron(II) o-Semiquinonate Complex. Inorg Chem 2017; 56:10481-10495. [PMID: 28809555 PMCID: PMC6200398 DOI: 10.1021/acs.inorgchem.7b01491] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The iron(II) semiquinonate character within the iron(III) catecholate species has been proposed by numerous studies to account for the O2 reactivity of intradiol catechol dioxygenases, but a well-characterized iron(II) semiquinonate species that exhibits intradiol cleaving reactivity has not yet been reported. In this study, a detailed electronic structure description of the first iron(II) o-semiquinonate complex, [PhTttBu]Fe(phenSQ) [PhTttBu = phenyltris(tert-butylthiomethyl)borate; phenSQ = 9,10-phenanthrenesemiquinonate; Wang et al. Chem. Commun. 2014, 50, 5871-5873], was generated through a combination of electronic and Mössbauer spectroscopies, SQUID magnetometry, and density functional theory (DFT) calculations. [PhTttBu]Fe(phenSQ) reacts with O2 to generate an intradiol cleavage product, diphenic anhydride, in 16% yield. To assess the dependence of the intradiol reactivity on the identity of the metal ion, the nickel analogue, [PhTttBu]Ni(phenSQ), and its derivative, [PhTttBu]Ni(3,5-DBSQ) (3,5-DBSQ = 3,5-di-tert-butyl-1,2-semiquinonate), were prepared and characterized by X-ray crystallography, mass spectrometry, 1H NMR and electronic spectroscopies, and SQUID magnetometry. DFT calculations, evaluated on the basis of the experimental data, support the electronic structure descriptions of [PhTttBu]Ni(phenSQ) and [PhTttBu]Ni(3,5-DBSQ) as high-spin nickel(II) complexes with antiferromagnetically coupled semiquinonate ligands. Unlike its iron counterpart, [PhTttBu]Ni(phenSQ) decomposes slowly in an O2 atmosphere to generate 14% phenanthrenequinone with a negligible amount of diphenic anhydride. [PhTttBu]Ni(3,5-DBSQ) does not react with O2. This dramatic effect of the metal-ion identity supports the hypothesis that a metal(III) alkylperoxo species serves as an intermediate in the intradiol cleaving reactions. The redox properties of all three complexes were probed using cyclic voltammetry and differential pulse voltammetry, which indicate an inner-sphere electron-transfer mechanism for the formation of phenanthrenequinone. The lack of O2 reactivity of [PhTttBu]Ni(3,5-DBSQ) can be rationalized by the high redox potential of the metal-ligated 3,5-DBSQ/3,5-DBQ couple.
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Affiliation(s)
- Peng Wang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Michelle M. Killian
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Mohamed R. Saber
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Tian Qiu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P. A. Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Codrina V. Popescu
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Kim R. Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Thomas C. Brunold
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Charles G. Riordan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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4
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Protein effects in non-heme iron enzyme catalysis: insights from multiscale models. J Biol Inorg Chem 2016; 21:645-57. [DOI: 10.1007/s00775-016-1374-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/20/2016] [Indexed: 01/09/2023]
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5
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Qi Y, Lu J, Lai W. Insights into the Reaction Mechanism of Aromatic Ring Cleavage by Homogentisate Dioxygenase: A Quantum Mechanical/Molecular Mechanical Study. J Phys Chem B 2016; 120:4579-90. [PMID: 27119315 DOI: 10.1021/acs.jpcb.6b03006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To elucidate the reaction mechanism of the ring cleavage of homogentisate by homogentisate dioxygenase, quantum mechanical/molecular mechanical (QM/MM) calculations were carried out by using two systems in different protonation states of the substrate C2 hydroxyl group. When the substrate C2 hydroxyl group is ionized (the ionized pathway), the superoxo attack on the substrate is the rate-limiting step in the catalytic cycle, with a barrier of 15.9 kcal/mol. Glu396 was found to play an important role in stabilizing the bridge species and its O-O cleavage product by donating a proton via a hydrogen-bonded water molecule. When the substrate C2 hydroxyl group is not ionized (the nonionized pathway), the O-O bond cleavage of the bridge species is the rate-limiting step, with a barrier of 15.3 kcal/mol. The QM/MM-optimized geometries for the dioxygen and alkylperoxo complexes using the nonionized model (for the C2 hydroxyl group) are in agreement with the experimental crystal structures, suggesting that the C2 hydroxyl group is more likely to be nonionized.
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Affiliation(s)
- Yue Qi
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
| | - Jiarui Lu
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
| | - Wenzhen Lai
- Department of Chemistry, Renmin University of China , Beijing, 100872, China
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6
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Saito T, Kawakami T, Yamanaka S, Okumura M. Computational Study of Catalytic Reaction of Quercetin 2,4-Dioxygenase. J Phys Chem B 2015; 119:6952-62. [PMID: 25990020 DOI: 10.1021/acs.jpcb.5b03564] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a quantum mechanics/molecular mechanics (QM/MM) and QM-only study on the oxidative ring-cleaving reaction of quercetin catalyzed by quercetin 2,4-dioxygenase (2,4-QD). 2,4-QD has a mononuclear type 2 copper center and incorporates two oxygen atoms at C2 and C4 positions of the substrate. It has not been clear whether dioxygen reacts with a copper ion or a substrate radical as the first step. We have found that dioxygen is more likely to bind to a Cu(2+) ion, involving the dissociation of the substrate from the copper ion. Then a Cu(2+)-alkylperoxo complex can be generated. Comparison of geometry and stability between QM-only and QM/MM results strongly indicates that steric effects of the protein environment contribute to maintain the orientation of the substrate dissociated from the copper center. The present QM/MM results also highlight that a prior rearrangement of the Cu(2+)-alkylperoxo complex and a subsequent hydrogen bond switching assisted by the movement of Glu73 can facilitate formation of an endoperoxide intermediate selectively.
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Affiliation(s)
- Toru Saito
- †Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.,‡Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology (JST) Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Takashi Kawakami
- †Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shusuke Yamanaka
- †Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.,‡Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology (JST) Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Mitsutaka Okumura
- †Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.,‡Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology (JST) Agency, Kawaguchi, Saitama 332-0012, Japan
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7
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Tichnell CR, Shultz DA, Popescu CV, Sokirniy I, Boyle PD. Synthesis, Characterization, and Photophysical Studies of an Iron(III) Catecholate–Nitronylnitroxide Spin-Crossover Complex. Inorg Chem 2015; 54:4466-74. [DOI: 10.1021/acs.inorgchem.5b00298] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher R. Tichnell
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - David A. Shultz
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Codrina V. Popescu
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Ivan Sokirniy
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Paul D. Boyle
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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8
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Lebedev AS, Orlov VY. Analysis of functionalized arenes degradation pathways in model water-organic media. APPL BIOCHEM MICRO+ 2014. [DOI: 10.1134/s0003683814040073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Wang P, Yap GPA, Riordan CG. Five-coordinate MII-semiquinonate (M = Fe, Mn, Co) complexes: reactivity models of the catechol dioxygenases. Chem Commun (Camb) 2014; 50:5871-3. [DOI: 10.1039/c3cc49143a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first mononuclear iron(ii)-semiquinonate has been prepared. Analogous manganese and cobalt adducts are reported, including a cobalt(ii)-semiquinonate that exhibits O2-mediated intradiol oxidation.
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Affiliation(s)
- Peng Wang
- Department of Chemistry & Biochemistry
- University of Delaware
- Newark, USA
| | - Glenn P. A. Yap
- Department of Chemistry & Biochemistry
- University of Delaware
- Newark, USA
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10
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Mahal A, Goshisht MK, Khullar P, Kumar H, Singh N, Kaur G, Bakshi MS. Protein mixtures of environmentally friendly zein to understand protein–protein interactions through biomaterials synthesis, hemolysis, and their antimicrobial activities. Phys Chem Chem Phys 2014; 16:14257-70. [DOI: 10.1039/c4cp01457j] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Protein–protein interactions through biomaterials synthesis for biological applications.
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Affiliation(s)
- Aabroo Mahal
- Department of Chemistry
- B.B.K. D.A.V. College for Women
- Amritsar 143005, India
- Department of Chemistry
- Dr. B. R. Ambedkar National Institute of Technology
| | - Manoj Kumar Goshisht
- Department of Chemistry
- B.B.K. D.A.V. College for Women
- Amritsar 143005, India
- Department of Chemistry
- Dr. B. R. Ambedkar National Institute of Technology
| | - Poonam Khullar
- Department of Chemistry
- B.B.K. D.A.V. College for Women
- Amritsar 143005, India
| | - Harsh Kumar
- Department of Chemistry
- Dr. B. R. Ambedkar National Institute of Technology
- Jalandhar-144011, India
| | - Narinder Singh
- Department of Chemistry
- Indian Institute of Technology Ropar
- Rupnagar-140001, India
| | - Gurinder Kaur
- Nanotechnology Research Laboratory
- College of North Atlantic
- Labrador City, NL A2V 2K7 Canada
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11
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Pápai M, Vankó G, de Graaf C, Rozgonyi T. Theoretical Investigation of the Electronic Structure of Fe(II) Complexes at Spin-State Transitions. J Chem Theory Comput 2012; 9:509-519. [PMID: 25821416 PMCID: PMC4358629 DOI: 10.1021/ct300932n] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Indexed: 01/30/2023]
Abstract
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The electronic structure relevant to low spin (LS)↔high
spin (HS) transitions in Fe(II) coordination compounds with a FeN6 core are studied. The selected [Fe(tz)6]2+ (1) (tz = 1H-tetrazole), [Fe(bipy)3]2+ (2) (bipy = 2,2′-bipyridine), and [Fe(terpy)2]2+ (3) (terpy = 2,2′:6′,2″-terpyridine)
complexes have been actively studied experimentally, and with their
respective mono-, bi-, and tridentate ligands, they constitute a comprehensive
set for theoretical case studies. The methods in this work include
density functional theory (DFT), time-dependent DFT (TD-DFT), and
multiconfigurational second order perturbation theory (CASPT2). We
determine the structural parameters as well as the energy splitting
of the LS–HS states (ΔEHL) applying the above methods and comparing their performance. We
also determine the potential energy curves representing the ground
and low-energy excited singlet, triplet, and quintet d6 states along the mode(s) that connect the LS and HS states. The
results indicate that while DFT is well suited for the prediction
of structural parameters, an accurate multiconfigurational approach
is essential for the quantitative determination of ΔEHL. In addition, a good qualitative agreement
is found between the TD-DFT and CASPT2 potential energy curves. Although
the TD-DFT results might differ in some respect (in our case, we found
a discrepancy at the triplet states), our results suggest that this
approach, with due care, is very promising as an alternative for the
very expensive CASPT2 method. Finally, the two-dimensional (2D) potential
energy surfaces above the plane spanned by the two relevant configuration
coordinates in [Fe(terpy)2]2+ were computed
at both the DFT and CASPT2 levels. These 2D surfaces indicate that
the singlet–triplet and triplet–quintet states are separated
along different coordinates, i.e., different vibration modes. Our
results confirm that in contrast to the case of complexes with mono-
and bidentate ligands, the singlet–quintet transitions in [Fe(terpy)2]2+ cannot be described using a single configuration
coordinate.
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Affiliation(s)
- Mátyás Pápai
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary
| | - György Vankó
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary
| | - Coen de Graaf
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain ; Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Spain
| | - Tamás Rozgonyi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1025 Budapest, Pusztaszeri út 59-67, Hungary
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12
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Metal-to-metal charge-transfer transitions: reliable excitation energies from ab initio calculations. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1264-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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