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Shapterhasmi T, Palani N, Velusamy M, Bhuvanesh NS, Sundaravel K, Easwaramoorthi S. Iron(III) Complexes of Pyrrolidine and Piperidine Appended Tridentate 3N Donor Ligands as Models for Catechol Dioxygenase Enzymes. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.120924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Biological Inspirations: Iron Complexes Mimicking the Catechol Dioxygenases. MATERIALS 2021; 14:ma14123250. [PMID: 34204660 PMCID: PMC8231159 DOI: 10.3390/ma14123250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/18/2022]
Abstract
Within the broad group of Fe non-heme oxidases, our attention was focused on the catechol 1,2- and 2,3-dioxygenases, which catalyze the oxidative cleavage of aromatic rings. A large group of Fe complexes with N/O ligands, ranging from N3 to N2O2S, was developed to mimic the activity of these enzymes. The Fe complexes discussed in this work can mimic the intradiol/extradiol catechol dioxygenase reaction mechanism. Electronic effects of the substituents in the ligand affect the Lewis acidity of the Fe center, increasing the ability to activate dioxygen and enhancing the catalytic activity of the discussed biomimetic complexes. The ligand architecture, the geometric isomers of the complexes, and the substituent steric effects significantly affect the ability to bind the substrate in a monodentate and bidentate manner. The substrate binding mode determines the preferred mechanism and, consequently, the main conversion products. The preferred mechanism of action can also be affected by the solvents and their ability to form the stable complexes with the Fe center. The electrostatic interactions of micellar media, similar to SDS, also control the intradiol/extradiol mechanisms of the catechol conversion by discussed biomimetics.
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Zhang Y, Xing F, Zhu S. Structures and Chromogenic Ion-Pair Recognition of a Catechol-Functionalized 1,8-Anthraquinone Macrocycle in Dimethyl Sulfoxide. Inorg Chem 2021; 60:5042-5053. [PMID: 33706508 DOI: 10.1021/acs.inorgchem.1c00083] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A lariat anthraquinone macrocycle functionalized with catechol (H2L) was synthesized via the Mannich reaction. The Mannich base H2L can be partially decomposed into L1·3H2O and HL1·NO3·2H2O in the presence of tetrabutylammonium hydroxide/Al(NO3)3·9H2O in dimethyl sulfoxide (DMSO). Free L1·3H2O is essentially coplanar, while protonated HL1·NO3·2H2O is highly distorted. Dark-green FeCl3·H2L·2H2O powder and Fe2(HL)2Cl4 crystal can be isolated from ethanol (C2H5OH) in high/low H2L concentration. Anthraquinone in H2L is essentially coplanar but distorted in Fe2(HL)2Cl4. The Fe(III) ion in Fe2(HL)2Cl4 adopts a less common five-coordination with three catecholate O and two Cl atoms in the dimer. The distortion of inbound C═O is much higher than that of outbound C═O in anthraquinone in all of these compounds. H2L responds to chlorides of Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Fe3+, Cu2+, Zn2+, and Al3+ in a DMSO solution, which can be observed by differential pulse voltammetry, UV-vis, and 1H NMR. All of these metal ions shift Ep of anthraquinone to positive, especially the second reduction peak of anthraquinone. Fe3+, Zn2+, and Al3+ change the reduction of catechol fundamentally. H2L (0.50 mM) shows a chromogenic response to FeCl3 and Fe(NO3)3 to form uncommon 2:1 and 3:2 (H2L/Fe) complexes, both peaking at 748 nm in DMSO. In the presence of 2 equiv of sodium hydroxide (NaOH), the 748 nm absorbance shifts to 777 nm, identical with Fe2(HL)2Cl4 in DMSO. Different from the fast reaction between H2L and FeCl3, Fe(NO3)3 reacts with H2L rather slowly in DMSO. Catechol can coordinate to FeCl3 without any deprotonation in C2H5OH and DMSO. H2L also shows a chromogenic response to fluorides and hydroxides, which peak at 670 and 684 nm, respectively, in DMSO. The binding ratio between H2L and F-/OH- is 1:2. In a higher concentration of hydroxides, a 684 nm greenish-blue 1:2 complex forms immediately, which gradually transforms to a red complex and peaks at ∼530 nm in minutes at room temperature. No color change can be observed in an C2H5OH solution in the presence of OH-.
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Affiliation(s)
- Yongrong Zhang
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Feifei Xing
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Shourong Zhu
- Department of Chemistry, Shanghai University, Shanghai 200444, China
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Chatterjee S, Banerjee S, Jana RD, Bhattacharya S, Chakraborty B, Jannuzzi SAV. Tuning the stereoelectronic factors of iron(II)-2-aminophenolate complexes for the reaction with dioxygen: oxygenolytic C-C bond cleavage vs. oxidation of complex. Dalton Trans 2021; 50:1901-1912. [PMID: 33475662 DOI: 10.1039/d0dt03316b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxidative C-C bond cleavage of 2-aminophenols mediated by transition metals and dioxygen is a topic of great interest. While the oxygenolytic C-C bond cleavage reaction relies on the inherent redox non-innocent property of 2-aminophenols, the metal complexes of 2-aminophenolates often undergo 1e-/2e- oxidation events (metal or ligand oxidation), instead of the direct addition of O2 for subsequent C-C bond cleavage. In this work, we report the isolation, characterization and dioxygen reactivity of a series of ternary iron(ii)-2-aminophenolate complexes [(TpPh,Me)FeII(X)], where X = 2-amino-4-tert-butylphenolate (4-tBu-HAP) (1); X = 2-amino-4,6-di-tert-butylphenolate (4,6-di-tBu-HAP) (2); X = 2-amino-4-nitrophenolate (4-NO2-HAP)(3); and X = 2-anilino-4,6-di-tert-butylphenolate (NH-Ph-4,6-di-tBu-HAP) (4) supported by a facial tridentate nitrogen donor ligand (TpPh,Me = hydrotris(3-phenyl-5-methylpyrazol-1-yl)borate). Another facial N3 ligand (TpPh2 = hydrotris(3,5-diphenyl-pyrazol-1-yl)borate) has been used to isolate an iron(ii)-2-anilino-4,6-di-tert-butylphenolate complex (5) for comparison. Both [(TpPh,Me)FeII(4-tBu-HAP)] (1) and [(TpPh,Me)FeII(4,6-di-tBu-HAP)] (2) undergo regioselective oxidative aromatic ring fission reaction of the coordinated 2-aminophenols to the corresponding 2-picolinic acids in the reaction with dioxygen. In contrast, complex [(TpPh,Me)FeII(4-NO2-HAP)] (3) displays metal based oxidation to form an iron(iii)-2-amidophenolate complex. Complexes [(TpPh,Me)FeII(NH-Ph-4,6-di-tBu-HAP)] (4) and [(TpPh2)FeII(NH-Ph-4,6-di-tBu-HAP)] (5) react with dioxygen to undergo 2e- oxidation with the formation of the corresponding iron(iii)-2-iminobenzosemiquinonato radical species implicating the importance of the -NH2 group in directing the C-C bond cleavage reactivity of 2-aminophenols. The systematic study presented in this work unravels the effect of the electronic and structural properties of the redox non-innocent 2-aminophenolate ring and the supporting ligand on the C-C bond cleavage reactivity vs. the metal/ligand oxidation of the complexes. The study further reveals that proper modulation of the stereoelectronic factors enables us to design a well synchronised proton transfer (PT) and dioxygen binding events for complexes 1 and 2 that mimic the structure and function of the nonheme enzyme 2-aminophenol-1,6-dioxygenase (APD).
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Affiliation(s)
- Sayanti Chatterjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
| | - Sridhar Banerjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
| | - Rahul Dev Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
| | - Shrabanti Bhattacharya
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
| | - Biswarup Chakraborty
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
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Wang P, Yap GP, Riordan CG. Synthesis, characterization and O2 reactivity of a bioinspired cobalt(II)-catecholate complex. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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A monomeric manganese(II) catecholato complex: Synthesis, crystal structure, and reactivity toward molecular oxygen. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rahaman R, Chakraborty B, Paine TK. Mimicking the Aromatic-Ring-Cleavage Activity of Gentisate-1,2-Dioxygenase by a Nonheme Iron Complex. Angew Chem Int Ed Engl 2016; 55:13838-13842. [DOI: 10.1002/anie.201607044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/30/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Rubina Rahaman
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
| | - Biswarup Chakraborty
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
| | - Tapan Kanti Paine
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
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Rahaman R, Chakraborty B, Paine TK. Mimicking the Aromatic-Ring-Cleavage Activity of Gentisate-1,2-Dioxygenase by a Nonheme Iron Complex. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Rubina Rahaman
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
| | - Biswarup Chakraborty
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
| | - Tapan Kanti Paine
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata- 700032 India
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Lakshman TR, Chatterjee S, Chakraborty B, Paine TK. Substrate-dependent aromatic ring fission of catechol and 2-aminophenol with O2 catalyzed by a nonheme iron complex of a tripodal N4 ligand. Dalton Trans 2016; 45:8835-44. [PMID: 27148606 DOI: 10.1039/c5dt04541j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The catalytic reactivity of an iron(ii) complex [(TPA)Fe(II)(CH3CN)2](2+) (1) (TPA = tris(2-pyridylmethyl)amine) towards oxygenative aromatic C-C bond cleavage of catechol and 2-aminophenol is presented. Complex 1 exhibits catalytic and regioselective C-C bond cleavage of 3,5-di-tert-butylcatechol (H2DBC) to form intradiol products, whereas it catalyzes extradiol-type C-C bond cleavage of 2-amino-4,6-di-tert-butylphenol (H2AP). The catalytic reactions are found to be pH-dependent and the complex exhibits maximum turnovers at pH 5 in acetonitrile-phthalate buffer. An iron(iii)-catecholate complex [(TPA)Fe(III)(DBC)](+) (2) is formed in the ring cleavage of catechol. In the extradiol-type cleavage of H2AP, an iron(iii)-2-iminobenzosemiquinonate complex [(TPA)Fe(III)(ISQ)](2+) (3) (ISQ = 4,6-di-tert-butyl-2-iminobenzosemiquinonate radical anion) is observed in the reaction pathway. This work shows the importance of the nature of 'redox non-innocent' substrates in governing the mode of ring fission reactivity.
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Affiliation(s)
- Triloke Ranjan Lakshman
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India.
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Cussó O, Ribas X, Costas M. Biologically inspired non-heme iron-catalysts for asymmetric epoxidation; design principles and perspectives. Chem Commun (Camb) 2015; 51:14285-98. [PMID: 26299813 DOI: 10.1039/c5cc05576h] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Iron coordination complexes with nitrogen and oxygen donor ligands have long since been known to react with peroxides producing powerful oxidizing species. These compounds can be regarded as simple structural and functional models of the active sites of non-heme iron dependent oxygenases. Research efforts during the last decade have uncovered basic principles and structural coordination chemistry motifs that permit us to control the chemistry that evolves when these iron complexes react with peroxides, in order to provide powerful metal-based, but at the same time selective, oxidising agents. Oxidation methodologies with synthetic value are currently emerging from this approach. The current review focuses on asymmetric epoxidation, a reaction which has large value in synthesis, and where iron/H2O2 based methodologies may represent not only a sustainable choice, but may also expand the scope of state-of-the-art oxidation methods. Basic principles that underlay catalyst design as well as H2O2 activation are discussed, whilst limitations and future perspectives are also reviewed.
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Affiliation(s)
- Olaf Cussó
- Institut de Química Computacional I Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Facultat de Ciéncies, Campus de Montilivi, 17071, Girona, Catalonia, Spain.
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Balamurugan M, Vadivelu P, Palaniandavar M. Iron(iii) complexes of tripodal tetradentate 4N ligands as functional models for catechol dioxygenases: the electronic vs. steric effect on extradiol cleavage. Dalton Trans 2014; 43:14653-68. [DOI: 10.1039/c3dt52145a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Bittner MM, Lindeman SV, Popescu CV, Fiedler AT. Dioxygen reactivity of biomimetic Fe(II) complexes with noninnocent catecholate, o-aminophenolate, and o-phenylenediamine ligands. Inorg Chem 2014; 53:4047-61. [PMID: 24697567 PMCID: PMC3998776 DOI: 10.1021/ic403126p] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Indexed: 11/28/2022]
Abstract
This study describes the O2 reactivity of a series of high-spin mononuclear Fe(II) complexes each containing the facially coordinating tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine ((Ph2)TIP) ligand and one of the following bidentate, redox-active ligands: 4-tert-butylcatecholate ((tBu)CatH(-)), 4,6-di-tert-butyl-2-aminophenolate ((tBu2)APH(-)), or 4-tert-butyl-1,2-phenylenediamine ((tBu)PDA). The preparation and X-ray structural characterization of [Fe(2+)((Ph2)TIP)((tBu)CatH)]OTf, [3]OTf and [Fe(2+)((Ph2)TIP)((tBu)PDA)](OTf)2, [4](OTf)2 are described here, whereas [Fe(2+)((Ph2)TIP)((tBu2)APH)]OTf, [2]OTf was reported in our previous paper [Bittner et al., Chem.-Eur. J. 2013, 19, 9686-9698]. These complexes mimic the substrate-bound active sites of nonheme iron dioxygenases, which catalyze the oxidative ring-cleavage of aromatic substrates like catechols and aminophenols. Each complex is oxidized in the presence of O2, and the geometric and electronic structures of the resulting complexes were examined with spectroscopic (absorption, EPR, Mössbauer, resonance Raman) and density functional theory (DFT) methods. Complex [3]OTf reacts rapidly with O2 to yield the ferric-catecholate species [Fe(3+)((Ph2)TIP)((tBu)Cat)](+) (3(ox)), which undergoes further oxidation to generate an extradiol cleavage product. In contrast, complex [4](2+) experiences a two-electron (2e(-)), ligand-based oxidation to give [Fe(2+)((Ph2)TIP)((tBu)DIBQ)](2+) (4(ox)), where DIBQ is o-diiminobenzoquinone. The reaction of [2](+) with O2 is also a 2e(-) process, yet in this case both the Fe center and (tBu2)AP ligand are oxidized; the resulting complex (2(ox)) is best described as [Fe(3+)((Ph2)TIP)((tBu2)ISQ)](+), where ISQ is o-iminobenzosemiquinone. Thus, the oxidized complexes display a remarkable continuum of electronic structures ranging from [Fe(3+)(L(2-))](+) (3(ox)) to [Fe(3+)(L(•-))](2+) (2(ox)) to [Fe(2+)(L(0))](2+) (4(ox)). Notably, the O2 reaction rates vary by a factor of 10(5) across the series, following the order [3](+) > [2](+) > [4](2+), even though the complexes have similar structures and Fe(3+/2+) redox potentials. To account for the kinetic data, we examined the relative abilities of the title complexes to bind O2 and participate in H-atom transfer reactions. We conclude that the trend in O2 reactivity can be rationalized by accounting for the role of proton transfer(s) in the overall reaction.
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Affiliation(s)
- Michael M. Bittner
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Codrina V. Popescu
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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Sankaralingam M, Saravanan N, Anitha N, Suresh E, Palaniandavar M. Biomimetic iron(iii) complexes of facially and meridionally coordinating tridentate 3N ligands: tuning of regioselective extradiol dioxygenase activity in organized assemblies. Dalton Trans 2014; 43:6828-41. [DOI: 10.1039/c3dt52350k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bittner MM, Kraus D, Lindeman SV, Popescu CV, Fiedler AT. Synthetic, spectroscopic, and DFT studies of iron complexes with iminobenzo(semi)quinone ligands: implications for o-aminophenol dioxygenases. Chemistry 2013; 19:9686-98. [PMID: 23744733 PMCID: PMC3965334 DOI: 10.1002/chem.201300520] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/17/2013] [Indexed: 11/10/2022]
Abstract
The oxidative C-C bond cleavage of o-aminophenols by nonheme Fe dioxygenases is a critical step in both human metabolism (the kynurenine pathway) and the microbial degradation of nitroaromatic pollutants. The catalytic cycle of o-aminophenol dioxygenases (APDOs) has been proposed to involve formation of an Fe(II)/O2/iminobenzosemiquinone complex, although the presence of a substrate radical has been called into question by studies of related ring-cleaving dioxygenases. Recently, we reported the first synthesis of an iron(II) complex coordinated to an iminobenzosemiquinone (ISQ) ligand, namely, [Fe((Ph2)Tp)((tBu)ISQ)] (2a; where (Ph2)Tp=hydrotris(3,5-diphenylpyrazol-1-yl)borate and (tBu)ISQ is the radical anion derived from 2-amino-4,6-di-tert-butylphenol). In the current manuscript, density functional theory (DFT) calculations and a wide variety of spectroscopic methods (electronic absorption, Mössbauer, magnetic circular dichroism, and resonance Raman) were employed to obtain detailed electronic-structure descriptions of 2a and its one-electron oxidized derivative [3a](+). In addition, we describe the synthesis and characterization of a parallel series of complexes featuring the neutral supporting ligand tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine ((Ph2)TIP). The isomer shifts of about 0.97 mm s(-1) obtained through Mössbauer experiments confirm that 2a (and its (Ph2)TIP-based analogue [2b](+)) contain Fe(II) centers, and the presence of an ISQ radical was verified by analysis of the absorption spectra in light of time-dependent DFT calculations. The collective spectroscopic data indicate that one-electron oxidation of the Fe(II)-ISQ complexes yields complexes ([3a](+) and [3b](2+)) with electronic configurations between the Fe(III)-ISQ and Fe(II)-IBQ limits (IBQ=iminobenzoquinone), highlighting the ability of o-amidophenolates to access multiple oxidation states. The implications of these results for the mechanism of APDOs and other ring-cleaving dioxygenases are discussed.
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Affiliation(s)
- Michael M. Bittner
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - David Kraus
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Codrina V. Popescu
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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Komatsuzaki H, Shiota A, Hazawa S, Itoh M, Miyamura N, Miki N, Takano Y, Nakazawa J, Inagaki A, Akita M, Hikichi S. Manganese(II) semiquinonato and manganese(III) catecholato complexes with tridentate ligand: modeling the substrate-binding state of manganese-dependent catechol dioxygenase and reactivity with molecular oxygen. Chem Asian J 2013; 8:1115-9. [PMID: 23512755 DOI: 10.1002/asia.201300029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/19/2013] [Indexed: 11/06/2022]
Abstract
Catecholate catwalk: Monomeric manganese(III) catecholato and manganese(II) semiquinonato complexes as the substrate-binding model of catechol dioxygenase have been synthesized and structurally characterized. The semiquinonato complex reacted with molecular oxygen to give ring-cleaved products and benzoquinone in the catalytic condition.
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Affiliation(s)
- Hidehito Komatsuzaki
- Department of Chemistry and Material Engineering, Ibaraki National College of Technology, 866 Nakane, Hitachinaka, 312-8508, Japan.
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Váradi T, Pap JS, Giorgi M, Párkányi L, Csay T, Speier G, Kaizer J. Iron(III) complexes with meridional ligands as functional models of intradiol-cleaving catechol dioxygenases. Inorg Chem 2013; 52:1559-69. [PMID: 23320898 DOI: 10.1021/ic302378r] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Six dichloroiron(III) complexes of 1,3-bis(2'-arylimino)isoindoline (BAIH) with various N-donor aryl groups have been characterized by spectroscopy (infrared, UV-vis), electrochemistry (cyclic voltammetry), microanalysis, and in two cases X-ray crystallography. The structurally characterized Fe(III)Cl(2)(L(n)) complexes (n = 3, L(3) = 1,3-bis(2'-thiazolylimino)isoindoline and n = 5, L(5) = 1,3-bis(4-methyl-2'-piridylimino)isoindoline) are five-coordinate, trigonal bipyramidal with the isoindoline ligands occupying the two axial and one equatorial positions meridionally. These compounds served as precursors for catechol dioxygenase models that were formed in solution upon addition of 3,5-di-tert-butylcatechol (H(2)DBC) and excess triethylamine. These adducts react with dioxygen in N,N-dimethylformamide, and the analysis of the products by chromatography and mass spectrometry showed high intradiol over extradiol selectivity (the intradiol/extradiol product ratios varied between 46.5 and 6.5). Kinetic measurements were performed by following the change in the intensity of the catecholate to iron ligand-to-metal charge transfer (LMCT) band, the energy of which is influenced by the isoindolinate-ligand (827-960 nm). In combination with electrochemical investigations the kinetic studies revealed an inverse trend between reaction rates and oxidation potentials associated with the coordinated DBC(2-). On the basis of these results, a substrate activation mechanism is suggested for this system in which the geometry of the peroxide-bridged intermediate may be of key importance in regioselectivity.
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Affiliation(s)
- Tünde Váradi
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Hungary
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Chatterjee S, Sheet D, Paine TK. Catalytic and regiospecific extradiol cleavage of catechol by a biomimetic iron complex. Chem Commun (Camb) 2013; 49:10251-3. [DOI: 10.1039/c3cc44124e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Ikeda A, Hoshino K, Komatsuzaki H, Satoh M, Nakazawa J, Hikichi S. O2 activation and external substrate oxidation capability of a Co(ii)–semiquinonato complex. NEW J CHEM 2013. [DOI: 10.1039/c3nj00215b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chakraborty B, Paine TK. Aromatic ring cleavage of 2-amino-4-tert-butylphenol by a nonheme iron(II) complex: functional model of 2-aminophenol dioxygenases. Angew Chem Int Ed Engl 2012. [PMID: 23197337 DOI: 10.1002/anie.201206922] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Biswarup Chakraborty
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
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Chakraborty B, Paine TK. Aromatic Ring Cleavage of 2-Amino-4-tert-butylphenol by a Nonheme Iron(II) Complex: Functional Model of 2-Aminophenol Dioxygenases. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Baum AE, Park H, Wang D, Lindeman SV, Fiedler AT. Structural, spectroscopic, and electrochemical properties of nonheme Fe(II)-hydroquinonate complexes: synthetic models of hydroquinone dioxygenases. Dalton Trans 2012; 41:12244-53. [PMID: 22930005 PMCID: PMC3891569 DOI: 10.1039/c2dt31504a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using the tris(3,5-diphenylpyrazol-1-yl)borate ((Ph2)Tp) supporting ligand, a series of mono- and dinuclear ferrous complexes containing hydroquinonate (HQate) ligands have been prepared and structurally characterized with X-ray crystallography. The monoiron(II) complexes serve as faithful mimics of the substrate-bound form of hydroquinone dioxygenases (HQDOs) - a family of nonheme Fe enzymes that catalyze the oxidative cleavage of 1,4-dihydroxybenzene units. Reflecting the variety of HQDO substrates, the synthetic complexes feature both mono- and bidentate HQate ligands. The bidentate HQates cleanly provide five-coordinate, high-spin Fe(II) complexes with the general formula [Fe((Ph2)Tp)(HL(X))] (1X), where HL(X) is a HQate(1-) ligand substituted at the 2-position with a benzimidazolyl (1A), acetyl (1B and 1C), or methoxy (1D) group. In contrast, the monodentate ligand 2,6-dimethylhydroquinone (H(2)L(F)) exhibited a greater tendency to bridge between two Fe(II) centers, resulting in formation of [Fe(2)((Ph2)Tp)(2)(μ-L(F))(MeCN)]·[2F(MeCN)]. However, addition of one equivalent of "free" pyrazole ((Ph2)pz) ligand provided the mononuclear complex, [Fe((Ph2)Tp)(HL(F))((Ph2)pz)]·[1F((Ph2)pz)], which is stabilized by an intramolecular hydrogen bond between the HL(F) and (Ph2)pz donors. Complex 1F((Ph2)pz) represents the first crystallographically-characterized example of a monoiron complex bound to an untethered HQate ligand. The geometric and electronic structures of the Fe/HQate complexes were further probed with spectroscopic (UV-vis absorption, (1)H NMR) and electrochemical methods. Cyclic voltammograms of complexes in the 1X series revealed an Fe-based oxidation between 0 and -300 mV (vs. Fc(+/0)), in addition to irreversible oxidation(s) of the HQate ligand at higher potentials. The one-electron oxidized species (1X(OX)) were examined with UV-vis absorption and electron paramagnetic resonance (EPR) spectroscopies.
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Affiliation(s)
- Amanda E. Baum
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | - Heaweon Park
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | - Denan Wang
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
| | | | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881
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Bittner MM, Baus JS, Lindeman SV, Fiedler AT. Synthesis and Structural Characterization of Iron(II) Complexes with Tris(imidazolyl)phosphane Ligands: A Platform for Modeling the 3-Histidine Facial Triad of Nonheme Iron Dioxygenases. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101282] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Long GJ, Grandjean F, Reger DL. Spin Crossover in Pyrazolylborate and Pyrazolylmethane Complexes. Top Curr Chem (Cham) 2012. [DOI: 10.1007/b13530] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Iron and cobalt complexes of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime ligand: Synthesis, characterization and reactivity studies. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0171-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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25
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Visvaganesan K, Ramachitra S, Palaniandavar M. Functional models for enzyme–substrate adducts of catechol dioxygenase enzymes: The Lewis basicity of facially coordinating tridentate phenolate ligands tunes the rate of dioxygenation and product selectivity. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.08.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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26
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Park H, Baus JS, Lindeman SV, Fiedler AT. Synthesis and Characterization of Fe(II) β-Diketonato Complexes with Relevance to Acetylacetone Dioxygenase: Insights into the Electronic Properties of the 3-Histidine Facial Triad. Inorg Chem 2011; 50:11978-89. [DOI: 10.1021/ic201115s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Heaweon Park
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Jacob S. Baus
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
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Tietz T, Limberg C, Stösser R, Ziemer B. Four-coordinate trispyrazolylboratomanganese and -iron complexes with a pyrazolato co-ligand: syntheses and properties as oxidation catalysts. Chemistry 2011; 17:10010-20. [PMID: 21744398 DOI: 10.1002/chem.201100343] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Indexed: 11/06/2022]
Abstract
A series of complexes of the type [(Tp(R1,R2))M(X)] (Tp = trispyrazolylborato) with R(1)/R(2) combinations Me/tBu, Ph/Me, iPr/iPr, Me/Me and for M = Mn or Fe coordinating [Pz(Me,tBu)](-) (Pz = pyrazolato) or Cl(-) as co-ligand X has been synthesised. Although the chloride complexes were very unreactive and stable in air, the pyrazolato series was far more reactive in contact with oxidants like O(2) and tBuOOH. The [(Tp(R1,R2))M(Pz(Me,tBu))] complexes proved to be active pre-catalysts for the oxidation of cyclohexene with tBuOOH, reaching turnover frequencies (TOFs) ranging between moderate and good in comparison to other manganese catalysts. Cyclohexene-3-one and cyclohexene-3-ol were always found to represent the main products, with cyclohexene oxide occasionally formed as a side product. The ratios of the different oxidation products varied with the reaction conditions: in the case of a peroxide/alkene ratio of 4:1, considerably more ketone than alcohol was obtained and cyclohexene oxide formation was almost negligible, whereas a ratio of 1:10 led to a significant increase of the alcohol proportion and to the formation of at least small amounts of the epoxide. Pre-treatment of the dissolved [(Tp(R1,R2))M(Pz(Me,tBu))] pre-catalysts with O(2) led to product distributions and TOFs that were very similar to those found in the absence of O(2), so that it may be argued that tBuOOH and O(2) both lead to the same active species. The results of EPR spectroscopy and ESI-MS suggest that the initial product of the reaction of [(Tp(Me,Me))Mn(Pz(Me,tBu))] with O(2) contains a Mn(III)(O)(2)Mn(IV) core. Prolonged exposure to O(2) leads to a different dinuclear complex containing three O-bridges and resulting in different TOFs/product distributions. Analogous findings were made for other complexes and formation of these overoxidised products may explain the deviation of the catalytic performances if the reactions are carried out in an O(2) atmosphere.
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Affiliation(s)
- Thomas Tietz
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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PALANIANDAVAR MALLAYAN, VISVAGANESAN KUSALENDIRAN. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of N-alkyl substitution on regioselectivity and reaction rate. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0110-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Anitha N, Palaniandavar M. Mononuclear iron(iii) complexes of 3N ligands in organized assemblies: spectral and redox properties and attainment of regioselective extradiol dioxygenase activity. Dalton Trans 2011; 40:1888-901. [DOI: 10.1039/c0dt01012j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Sundaravel K, Suresh E, Saminathan K, Palaniandavar M. Iron(III) complexes of N2O and N3O donor ligands as functional models for catechol dioxygenase enzymes: ether oxygen coordination tunes the regioselectivity and reactivity. Dalton Trans 2011; 40:8092-107. [DOI: 10.1039/c0dt01598a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Karuppasamy Sundaravel
- Centre for Bioinorganic Chemistry, School of Chemistry, Bharathidasan University, Tiruchirappalli, 620 024, Tamilnadu, India
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Sundaravel K, Suresh E, Palaniandavar M. Iron(III) complexes of tridentate N3 ligands as models for catechol dioxygenases: Stereoelectronic effects of pyrazole coordination. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.04.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Paria S, Halder P, Paine TK. A Functional Model of Extradiol-Cleaving Catechol Dioxygenases: Mimicking the 2-His-1-Carboxylate Facial Triad. Inorg Chem 2010; 49:4518-23. [DOI: 10.1021/ic902462k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sayantan Paria
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Partha Halder
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Tapan Kanti Paine
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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Dhanalakshmi T, Suresh E, Palaniandavar M. Synthesis, structure, spectra and reactivity of iron(III) complexes of imidazole and pyrazole containing ligands as functional models for catechol dioxygenases. Dalton Trans 2009:8317-28. [PMID: 19789784 DOI: 10.1039/b903602d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of new 1 : 1 iron(iii) complexes of the type [Fe()Cl(3)], where is a tridentate 3N donor ligand, has been isolated and studied as functional models for catechol dioxygenases. The ligands (1-methyl-1H-imidazol-2-ylmethyl)pyrid-2-ylmethyl-amine (), N,N-dimethyl-N'-(1-methyl-1H-imidazol-2-ylmethyl)ethane-1,2-diamine () and N-(1-methyl-1H-imidazol-2-ylmethyl)-N'-phenylethane-1,2-diamine () are linear while the ligands tris(1-pyrazolyl)methane (), tris(3,5-dimethyl-1-pyrazolyl)methane () and tris(3-iso-propylpyrazolyl)methane () are tripodal ones. All the complexes have been characterized by spectral and electrochemical methods. The X-ray crystal structure of the dinuclear catecholate adduct [Fe()(TCC)](2)O, where TCC(2-) is a tetrachlorocatecholate dianion, has been successfully determined. In this complex both the iron(iii) atoms are bridged by a mu-oxo group and each iron(iii) center possesses a distorted octahedral coordination geometry in which the ligand is facially coordinated and the remaining coordination sites are occupied by the TCC(2-) dianion. Spectral studies suggest that addition of a base like Et(3)N induces the mononuclear complex species [Fe()(TCC)Cl] to dimerize forming a mu-oxo-bridged complex. The spectral and electrochemical properties of the catecholate adducts of the complexes generated in situ reveal that a systematic variation in the ligand donor atom type significantly influences the Lewis acidity of the iron(iii) center and hence the interaction of the complexes with simple and substituted catechols. The 3,5-di-tert-butylcatecholate (DBC(2-)) adducts of the type [Fe()(DBC)Cl], where is a linear tridentate ligand (), undergo mainly oxidative intradiol cleavage of the catechol in the presence of dioxygen. Also, the extradiol-to-intradiol product selectivity (E : I) is enhanced upon removal of the coordinated chloride ion in these adducts to obtain [Fe()(DBC)(Sol)](+) and upon incorporating coordinated N-methylimidazolyl nitrogen in them. In contrast to the iron(iii) complexes of imidazole-based ligands, those of the tripodal pyrazole-based ligands yield major amounts of the oxidized product benzoquinone and small amounts of both intra- and extradiol products. One of the pyrazole arms coordinated in the equatorial plane of these sterically constrained complexes is substituted by a solvent molecule upon adduct formation with DBC(2-), which encourages molecular oxygen to attack this site leading to benzoquinone formation. The DBSQ/DBC(2-) redox potentials of both the imidazole- and pyrazole-based complexes fall in the narrow range of -0.186 to -0.214 V supporting this proposal.
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Functional model for catecholase-like activity: Synthesis, structure, spectra, and catalytic activity of iron(III) complexes with substituted-salicylaldimine ligands. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.06.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Wagner M, Limberg C, Tietz T. A Novel Tripodal Ligand Containing Three DifferentN-Heterocyclic Donor Functions and Its Application in Catechol Dioxygenase Mimicking. Chemistry 2009; 15:5567-76. [DOI: 10.1002/chem.200802591] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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Mayilmurugan R, Stoeckli-Evans H, Palaniandavar M. Novel Iron(III) Complexes of Sterically Hindered 4N Ligands: Regioselectivity in Biomimetic Extradiol Cleavage of Catechols. Inorg Chem 2008; 47:6645-58. [DOI: 10.1021/ic702410d] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ramasamy Mayilmurugan
- School of Chemistry, Bharathidasan University, Tiruchirapalli 620 024, India, and Department of Chemistry, University of Neuchatel, Neuchatel, Switzerland
| | - Helen Stoeckli-Evans
- School of Chemistry, Bharathidasan University, Tiruchirapalli 620 024, India, and Department of Chemistry, University of Neuchatel, Neuchatel, Switzerland
| | - Mallayan Palaniandavar
- School of Chemistry, Bharathidasan University, Tiruchirapalli 620 024, India, and Department of Chemistry, University of Neuchatel, Neuchatel, Switzerland
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Sundaravel K, Dhanalakshmi T, Suresh E, Palaniandavar M. Synthesis, structure, spectra and reactivity of iron(iii) complexes of facially coordinating and sterically hindering 3N ligands as models for catechol dioxygenases. Dalton Trans 2008:7012-25. [DOI: 10.1039/b809142k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bruijnincx PCA, van Koten G, Klein Gebbink RJM. Mononuclear non-heme iron enzymes with the 2-His-1-carboxylate facial triad: recent developments in enzymology and modeling studies. Chem Soc Rev 2008; 37:2716-44. [DOI: 10.1039/b707179p] [Citation(s) in RCA: 412] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Visvaganesan K, Mayilmurugan R, Suresh E, Palaniandavar M. Iron(III) Complexes of Tridentate 3N Ligands as Functional Models for Catechol Dioxygenases: The Role of Ligand N-alkyl Substitution and Solvent on Reaction Rate and Product Selectivity. Inorg Chem 2007; 46:10294-306. [DOI: 10.1021/ic700822y] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kusalendiran Visvaganesan
- School of Chemistry, Bharathidasan University, Tiruchirappalli-620 024, India, Analytical Science Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, India
| | - Ramasamy Mayilmurugan
- School of Chemistry, Bharathidasan University, Tiruchirappalli-620 024, India, Analytical Science Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, India
| | - Eringathodi Suresh
- School of Chemistry, Bharathidasan University, Tiruchirappalli-620 024, India, Analytical Science Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, India
| | - Mallayan Palaniandavar
- School of Chemistry, Bharathidasan University, Tiruchirappalli-620 024, India, Analytical Science Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, India
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Functional model for intradiol-cleaving catechol 1,2-dioxygenase: Synthesis, structure, spectra, and catalytic activity of iron(III) complexes with substituted salicylaldimine ligands. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2007.02.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Bruijnincx PCA, Lutz M, Spek AL, Hagen WR, Weckhuysen BM, van Koten G, Gebbink RJMK. Modeling the 2-His-1-Carboxylate Facial Triad: Iron−Catecholato Complexes as Structural and Functional Models of the Extradiol Cleaving Dioxygenases. J Am Chem Soc 2007; 129:2275-86. [PMID: 17266307 DOI: 10.1021/ja064816x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mononuclear iron(II)- and iron(III)-catecholato complexes with three members of a new 3,3-bis(1-alkylimidazol-2-yl)propionate ligand family have been synthesized as models of the active sites of the extradiol cleaving catechol dioxygenases. These enzymes are part of the superfamily of dioxygen-activating mononuclear non-heme iron enzymes that feature the so-called 2-His-1-carboxylate facial triad. The tridentate, tripodal, and monoanionic ligands used in this study include the biologically relevant carboxylate and imidazole donor groups. The structure of the mononuclear iron(III)-tetrachlorocatecholato complex [Fe(L3)(tcc)(H2O)] was determined by single-crystal X-ray diffraction, which shows a facial N,N,O capping mode of the ligand. For the first time, a mononuclear iron complex has been synthesized, which is facially capped by a ligand offering a tridentate Nim,Nim,Ocarb donor set, identical to the endogenous ligands of the 2-His-1-carboxylate facial triad. The iron complexes are five-coordinate in noncoordinating media, and the vacant coordination site is accessible for Lewis bases, e.g., pyridine, or small molecules such as dioxygen. The iron(II)-catecholato complexes react with dioxygen in two steps. In the first reaction the iron(II)-catecholato complexes rapidly convert to the corresponding iron(III) complexes, which then, in a second slow reaction, exhibit both oxidative cleavage and auto-oxidation of the substrate. Extradiol and intradiol cleavage are observed in noncoordinating solvents. The addition of a proton donor results in an increase in extradiol cleavage. The complexes add a new example to the small group of synthetic iron complexes capable of eliciting extradiol-type cleavage and provide more insight into the factors determining the regioselectivity of the enzymes.
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Affiliation(s)
- Pieter C A Bruijnincx
- Organic Chemistry and Catalysis Group, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Dhanalakshmi T, Bhuvaneshwari M, Palaniandavar M. Iron(III) complexes of certain meridionally coordinating tridentate ligands as models for non-heme iron enzymes: The role of carboxylate coordination. J Inorg Biochem 2006; 100:1527-34. [PMID: 16814389 DOI: 10.1016/j.jinorgbio.2006.05.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 04/13/2006] [Accepted: 05/10/2006] [Indexed: 11/18/2022]
Abstract
The iron(III) complexes [Fe(pda)Cl(H(2)O)(2)] (1), [Fe(tpy)Cl(3)] (2), and [Fe(bbp)Cl(3)] (3), where H(2)pda is pyridine-2,6-dicarboxylic acid, tpy is 2,2':6,2''-terpyridine and bbp is 2,6-bis(benzimidazolyl)pyridine, have been isolated and studied as functional models for the intradiol-cleaving catechol dioxygenase enzymes. Mixed ligand complexes of H(2)pda with the bidentate ligands 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) have been also prepared and studied. All the complexes have been characterized using absorption spectral and electrochemical methods. The spectral changes in the catecholate adducts of the complexes generated in situ have been investigated. Upon interacting the complexes with catecholate anions a low energy catecholate to iron(III) charge transfer band appears, which is similar to that observed for enzyme-substrate complexes. All the complexes catalyze the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H(2)dbc) in the presence of dioxygen. Interestingly, on replacing the pyridyl groups in 2 and the bulky benzimidazole groups in 3 by the carboxylate groups, the yields of the intradiol cleavage products of dioxygenation increases, 1 (50%)>2 (20%)>3 (10%). The higher intradiol yield for 1 has been ascribed to the meridional coordination of two carboxylate groups of pda(2-). In contrast to the trend in the intradiol cleavage yields, a tremendous decrease in the rate (200 times) is observed on replacing the two pyridyl moieties in 2 by two carboxylates as in 1 and a significant decrease in rate is observed on replacing the pyridyl moieties in 2 by strongly sigma-donating benzimidazole moieties as in 3. This is in conformity with the decrease in Lewis acidities of the iron(III) centers.
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Kurahashi T, Oda K, Sugimoto M, Ogura T, Fujii H. Trigonal-Bipyramidal Geometry Induced by an External Water Ligand in a Sterically Hindered Iron Salen Complex, Related to the Active Site of Protocatechuate 3,4-Dioxygenase. Inorg Chem 2006; 45:7709-21. [PMID: 16961363 DOI: 10.1021/ic060650p] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A unique distorted trigonal-bipyramidal geometry observed for the non-heme iron center in protocatechuate 3,4-dioxygenase (3,4-PCD) was carefully examined utilizing a sterically hindered iron salen complex, which well reproduces the endogenous His2Tyr2 donor set with water as an external ligand. X-ray crystal structures of a series of iron model complexes containing bis(3,5-dimesitylsalicylidene)-1,2-dimesitylethylenediamine indicate that a distorted trigonal-bipyramidal geometry is achieved upon binding of water as an external ligand. The extent of a structural change of the iron center from a preferred square-pyramidal to a distorted trigonal-bipyramidal geometry varies with the external ligand that is bound in the order Cl << EtO < H2O, which is consistent with the spectrochemical series. The distortion in the model system is not due to steric repulsions but electronic interactions between the external ligand and the iron center, as evidenced from the X-ray crystal structures of another series of iron model complexes with a less-hindered bis(3-xylylsalicylidene)-1,2-dimesitylethylenediamine ligand, as well as by density functional theory calculations. Further spectroscopic investigations indicate that a unique distorted trigonal-bipyramidal geometry is indeed maintained even in solution. The present model study provides a new viewpoint that a unique distorted trigonal-bipyramidal iron site might not be preorganized by a 3,4-PCD protein but could be electronically induced upon the binding of an external hydroxide ligand to the iron(III) center. The structural change induced by the external water ligand is also discussed in relation to the reaction mechanism of 3,4-PCD.
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Affiliation(s)
- Takuya Kurahashi
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787, Japan.
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Mechanistic study on regioselective oxygenation reaction of 1,2-quinones with peroxybenzoic acids: Relevant to mechanisms of catecholdioxygenases. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcata.2006.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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45
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Kervinen K, Bruijnincx PCA, Beale AM, Mesu JG, van Koten G, Klein Gebbink RJM, Weckhuysen BM. Zeolite Framework Stabilized Copper Complex Inspired by the 2-His-1-carboxylate Facial Triad Motif Yielding Oxidation Catalysts. J Am Chem Soc 2006; 128:3208-17. [PMID: 16522101 DOI: 10.1021/ja0567992] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The stabilization of a mononuclear copper(II) complex with one MIm2Pr ligand [MIm2Pr = 3,3-bis(1-methylimidazol-2-yl)propionate] in the supercages of zeolite Y was attempted, and the resulting materials were tested for their activity in oxidation catalysis. The preparation procedure yielded initially two species (labeled 1 and 2) within the pore system of the zeolite material, which differ in molecular structure and chemical composition as determined by UV/vis, ESR, IR, and XAFS spectroscopy. In species 1, the copper was found to be five-coordinated, with one MIm2Pr ligand in a facial-type NNO coordination toward copper, the other two coordination sites being occupied by oxygen atoms from either the zeolite framework and/or a water molecule. The total charge of this complex is 1+. In species 2, the copper is surrounded by two MIm2Pr ligands, both in a facial-type coordination mode, identical to the homogeneous Cu(MIm2Pr)2 complex. This neutral species 2 is easily washed out of the zeolite, whereas the mononuclear species 1 remains inside the zeolite material upon washing. The spectroscopic characteristics and activity for 3,5-di-tert-butylcatechol and benzyl alcohol oxidation of species 1 compared closely with that of the zeolite-immobilized Cu(histidine) complexes but differed from that of the homogeneous Cu(MIm2Pr)2 complex. It was therefore found that encapsulation in zeolite offers a route to stabilize a 5-fold-coordinated copper complex with novel catalytic properties. This 1:1 Cu(MIm2Pr) complex is not formed in solution.
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Affiliation(s)
- Kaisa Kervinen
- Department of Inorganic Chemistry and Catalysis, Utrecht University, Debye Institute, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands
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Desroches C, Pilet G, Szilágyi PÁ, Molnár G, Borshch SA, Bousseksou A, Parola S, Luneau D. Tetra- and Decanuclear Iron(II) Complexes of Thiacalixarene Macrocycles: Synthesis, Structure, Mössbauer Spectroscopy and Magnetic Properties. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200500640] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Velusamy M, Mayilmurugan R, Palaniandavar M. Functional models for catechol dioxygenases: Iron(III) complexes of cis-facially coordinating linear 3N ligands. J Inorg Biochem 2005; 99:1032-42. [PMID: 15833326 DOI: 10.1016/j.jinorgbio.2005.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 01/17/2005] [Accepted: 01/18/2005] [Indexed: 11/18/2022]
Abstract
A series of 1:1 iron(III) complexes of simple and sterically hindered tridentate 3N donor ligands have been synthesized and studied as functional models for catechol dioxygenases. All of them are of the type [FeLCl3], where L is bis(pyrid-2-yl-methyl)amine (L1), N,N-bis(benzimidazol-2-ylmethyl)amine (L2), N-methyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L3), N,N-dimethyl-N'-(pyrid-2-ylmethyl)-ethylenediamine (L4) and N-phenyl-N'-(pyrid-2-ylmethyl)ethylenediamine (L5). They have been characterised by spectral and electrochemical methods. The X-ray crystal structure of the complex [Fe(L4)Cl3] has been successfully determined. The complex crystallizes in the triclinic space group P1 with a = 7.250(6), b = 8.284(3), c = 12.409(4) angstroms, alpha = 80.84(3) degrees, beta = 86.76(6) degrees, gamma = 72.09(7) degrees and Z = 2. It possesses a distorted octahedral geometry in which the L4 ligand is cis-facially coordinated to iron(III) and the chloride ions occupy the remaining coordination sites. The systematic variation in the ligand donor atom type significantly influences the Lewis acidity of the iron(III) center and hence the binding interaction of the complexes with simple and substituted catechols. The spectroscopic and electrochemical properties of the catecholate complexes generated in situ have been investigated. All the complexes catalyze mainly the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H2DBC) in the presence of dioxygen, which is unexpected of the cis-facial coordination of the ligands. The rate of intradiol catechol cleavage reaction depends upon the Lewis acidity of iron(III) center and steric demand and hydrogen-bonding functionalities of the ligands. Interestingly, the electron-sink property of N-phenyl substituent in [Fe(L5)Cl3] complex leads to enhancement in rate of cleavage. All these observations provide support to the substrate activation mechanism proposed for intradiol-cleaving enzymes.
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Affiliation(s)
- Marappan Velusamy
- Department of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, India
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Costas M, Mehn MP, Jensen MP, Que L. Dioxygen Activation at Mononuclear Nonheme Iron Active Sites: Enzymes, Models, and Intermediates. Chem Rev 2004; 104:939-86. [PMID: 14871146 DOI: 10.1021/cr020628n] [Citation(s) in RCA: 2014] [Impact Index Per Article: 100.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miquel Costas
- Departament de Quimica, Universitat de Girona, 17071, Girona, Spain
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Velusamy M, Palaniandavar M, Gopalan RS, Kulkarni GU. Novel Iron(III) Complexes of Tripodal and Linear Tetradentate Bis(phenolate) Ligands: Close Relevance to Intradiol-Cleaving Catechol Dioxygenases. Inorg Chem 2003; 42:8283-93. [PMID: 14658880 DOI: 10.1021/ic020569w] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Four new iron(III) complexes of the bis(phenolate) ligands N,N-dimethyl-N',N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine [H2(L1)], N,N-dimethyl-N',N'-bis(2-hydroxy-4-nitrobenzyl)ethylenediamine [H2(L2)], N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine [H2(L3)], and N,N'-dimethyl-N,N'-bis(2-hydroxy-4-nitrobenzyl)ethylenediamine [H2(L4)] have been isolated and studied as structural and functional models for the intradiol-cleaving catechol 1,2-dioxygenases (CTD). The complexes [Fe(L1)Cl] (1), [Fe(L2)(H2O)Cl] (2), [Fe(L3)Cl] (3), and [Fe(L4)(H2O)Cl] (4) have been characterized using absorption spectral and electrochemical techniques. The single-crystal X-ray structures of the ligand H2(L1) and the complexes 1 and 2 have been successfully determined. The tripodal ligand H2(L1) containing a N2O2 donor set represents the metal-binding region of the iron proteins. Complex 1 contains an FeN2O2Cl chromophore with a novel trigonal bipyramidal coordination geometry. While two phenolate oxygens and an amine nitrogen constitute the trigonal plane, the other amine nitrogen and chloride ion are located in the axial positions. In contrast, 2 exhibits a rhombically distorted octahedral coordination geometry for the FeN2O3Cl chromophore. Two phenolate oxygen atoms, an amine nitrogen atom, and a water molecule are located on the corners of a square plane with the axial positions being occupied by the other nitrogen atom and chloride ion. The interaction of the complexes with a few monodentate bases and phenolates and differently substituted catechols have been investigated using absorption spectral and electrochemical methods. The effect of substituents on the phenolate rings on the electronic spectral features and FeIII/FeII redox potentials of the complexes are discussed. The interaction of the complexes with catecholate anions reveals changes in the phenolate to iron(III) charge-transfer band and also the appearance of a low-energy catecholate to iron(III) charge-transfer band similar to catechol dioxygenase-substrate complexes. The redox behavior of the 1:1 adducts of the complexes with 3,5-di-tert-butylcatechol (H2DBC) has been also studied. The reactivities of the present complexes with H2DBC have been studied and illustrated. Interestingly, only 2 and 4 catalyze the intradiol-cleavage of H2DBC, the rate of oxygenation being much faster for 4. Also 2, but not 4, yields an extradiol cleavage product. The reactivity of the complexes could be illustrated not on the basis of the Lewis acidity of the complexes alone but by assuming that the product release is the rate-determining phase of the catalytic reaction.
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Affiliation(s)
- Marappan Velusamy
- Department of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, India
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Funabiki T. Functional model oxygenations by nonheme iron complexes. ADVANCES IN CATALYTIC ACTIVATION OF DIOXYGEN BY METAL COMPLEXES 2003. [DOI: 10.1007/0-306-47816-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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