1
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Studies towards DIAD promoted N-demethylation of N,N-dimethylanilines. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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2
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Daya VP, Jagan R, Chand DK. Self-assembled discrete and polymeric cobalt(II) complexes of a carboxylate appended tripodal tetradentate ligand: reactivity with aerial dioxygen or aqueous hydrogen peroxide. J CHEM SCI 2022. [DOI: 10.1007/s12039-022-02049-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Abu‐Odeh M, Bleher K, Johnee Britto N, Comba P, Gast M, Jaccob M, Kerscher M, Krieg S, Kurth M. Pathways of the Extremely Reactive Iron(IV)-oxido complexes with Tetradentate Bispidine Ligands. Chemistry 2021; 27:11377-11390. [PMID: 34121233 PMCID: PMC8456976 DOI: 10.1002/chem.202101045] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Indexed: 11/07/2022]
Abstract
The nonheme iron(IV)-oxido complex trans-N3-[(L1 )FeIV =O(Cl)]+ , where L1 is a derivative of the tetradentate bispidine 2,4-di(pyridine-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1-one, is known to have an S=1 electronic ground state and to be an extremely reactive oxidant for oxygen atom transfer (OAT) and hydrogen atom abstraction (HAA) processes. Here we show that, in spite of this ferryl oxidant having the "wrong" spin ground state, it is the most reactive nonheme iron model system known so far and of a similar order of reactivity as nonheme iron enzymes (C-H abstraction of cyclohexane, -90 °C (propionitrile), t1/2 =3.5 sec). Discussed are spectroscopic and kinetic data, supported by a DFT-based theoretical analysis, which indicate that substrate oxidation is significantly faster than self-decay processes due to an intramolecular demethylation pathway and formation of an oxido-bridged diiron(III) intermediate. It is also shown that the iron(III)-chlorido-hydroxido/cyclohexyl radical intermediate, resulting from C-H abstraction, selectively produces chlorocyclohexane in a rebound process. However, the life-time of the intermediate is so long that other reaction channels (known as cage escape) become important, and much of the C-H abstraction therefore is unproductive. In bulk reactions at ambient temperature and at longer time scales, there is formation of significant amounts of oxidation product - selectively of chlorocyclohexane - and it is shown that this originates from oxidation of the oxido-bridged diiron(III) resting state.
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Affiliation(s)
- Mahmud Abu‐Odeh
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
| | - Katharina Bleher
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
| | | | - Peter Comba
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR) MathematikonIm Neuenheimer Feld 20569120HeidelbergGermany
| | - Michael Gast
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
| | | | - Marion Kerscher
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
| | - Saskia Krieg
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
| | - Marius Kurth
- Anorganisch-Chemisches InstitutUniversität HeidelbergINF 27069120HeidelbergGermany
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4
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Mukherjee G, Sastri CV. Eccentricities in Spectroscopy and Reactivity of Non‐Heme Metal Intermediates Contained in Bispidine Scaffolds. Isr J Chem 2020. [DOI: 10.1002/ijch.202000045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gourab Mukherjee
- Department of Chemistry Indian Institute of Technology Guwahati Guwahati, Assam 781039 India
| | - Chivukula V. Sastri
- Department of Chemistry Indian Institute of Technology Guwahati Guwahati, Assam 781039 India
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5
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Chakraborty B, Ghosh I, Jana RD, Paine TK. Oxidative C-N bond cleavage of (2-pyridylmethyl)amine-based tetradentate supporting ligands in ternary cobalt(ii)-carboxylate complexes. Dalton Trans 2020; 49:3463-3472. [PMID: 32103212 DOI: 10.1039/c9dt04438h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three mononuclear cobalt(ii)-carboxylate complexes, [(TPA)CoII(benzilate)]+ (1), [(TPA)CoII(benzoate)]+ (2) and [(iso-BPMEN)CoII(benzoate)]+ (3), of N4 ligands (TPA = tris(2-pyridylmethyl)amine and iso-BPMEN = N1,N1-dimethyl-N2,N2-bis((pyridin-2-yl)methyl)ethane-1,2-diamine) were isolated to investigate their reactivity toward dioxygen. Monodentate (η1) binding of the carboxylates to the metal centre favours the five-coordinate cobalt(ii) complexes (1-3) for dioxygen activation. Complex 1 slowly reacts with dioxygen to enable the oxidative decarboxylation of the coordinated α-hydroxy acid (benzilate). Prolonged exposure of the reaction solution of 2 to dioxygen results in the formation of [(DPA)CoIII(picolinate)(benzoate)]+ (4) and [CoIII(BPCA)2]+ (5) (DPA = di(2-picolyl)amine and HBPCA = bis(2-pyridylcarbonyl)amide), whereas only [(DPEA)CoIII(picolinate)(benzoate)]+ (6) (DPEA = N1,N1-dimethyl-N2-(pyridine-2-ylmethyl)-ethane-1,2-diamine) is isolated from the final oxidised solution of 3. The modified ligand DPA (or DPEA) is formed via the oxidative C-N bond cleavage of the supporting ligands. Further oxidation of the -CH2- moiety to -C([double bond, length as m-dash]O)- takes place in the transformation of DPA to HBPCA on the cobalt(ii) centre. Labelling experiments with 18O2 confirm the incorporation of oxygen atoms from molecular oxygen into the oxidised products. Mixed labelling studies with 16O2 and H2O18 strongly support the involvement of water in the C-N bond cleavage pathway. A comparison of the dioxygen reactivity of the cobalt complexes (1-3) with those of several other five-coordinate mononuclear complexes [(TPA)CoII(X)]+/2+ (X = Cl, CH3CN, acetate, benzoylformate, salicylate and phenylpyruvate) establishes the role of the carboxylate co-ligands in the activation of dioxygen and subsequent oxidative cleavage of the supporting ligands by a metal-oxygen oxidant.
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Affiliation(s)
- 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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6
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Anjana SS, Varghese B, Murthy NN. Coligand modulated oxidative O-demethylation of a methyl ether appended tetradentate N-ligand in Co(ii) complexes. Dalton Trans 2020; 49:3187-3197. [PMID: 31967148 DOI: 10.1039/c9dt04609g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Two Co(ii) complexes of the formula CoLOMeX2 (X = Cl- (1a); X = I- (1b)), where LOMe is 2-methoxy-N,N-bis(pyridin-2-ylmethyl) aniline, were synthesized and their structure, spectra and reactivity were studied. Upon oxidation of 1a and 1b, the ligand LOMe undergoes demethylation at the metal centre resulting in the formation of Co(iii) complexes with modified phenoxide ligands. This is the very first example of oxidative O-demethylation reported at a Co(ii) centre. The oxidative behaviour exhibits a striking dependence on the nature of coligands coordinated to the metal centre. The Co(ii) complex 1a with stronger chloro coligands requires a strong oxidising agent like t-BuOOH for oxidative demethylation and the subsequent formation of a mononuclear Co(iii) complex with a demethylated ligand, CoLO-Cl2 (2). On the other hand, complex 1b with weaker iodo coligands undergoes oxidation in the presence of the weak oxidant O2 to form a dihydroxo bridged binuclear Co(iii) complex [Co2(LO-)2(OH)2]2+ (3) with modified phenoxide ligands. The oxidation of 1b to 3 is monitored and the intermediate Co(ii) iodo aqua complex [CoLOMeI(H2O)]+ and Co(ii) diaqua complex [CoLOMe(H2O)2]2+ are isolated and characterised.
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Affiliation(s)
- S S Anjana
- Department of Chemistry, IIT Madras, Chennai 600 036, India.
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7
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Abstract
Radiometal based radiopharmaceuticals for imaging and therapy require selective ligands (bifunctional chelators, BFCs) that form metal complexes, which are inert against trans-chelation under physiological conditions, linked to a biological vector, directing them to the targeted tissue. Bispidine ligands with a very rigid backbone and widely variable donor sets are reviewed as an ideal class of BFCs, and recent applications are discussed.
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Affiliation(s)
- Peter Comba
- Ruprecht-Karls Universität Heidelberg
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR)
- 69120 Heidelberg
- Germany
| | - Marion Kerscher
- Ruprecht-Karls Universität Heidelberg
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR)
- 69120 Heidelberg
- Germany
| | - Katharina Rück
- Ruprecht-Karls Universität Heidelberg
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR)
- 69120 Heidelberg
- Germany
| | - Miriam Starke
- Ruprecht-Karls Universität Heidelberg
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR)
- 69120 Heidelberg
- Germany
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8
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Cantú Reinhard FG, Barman P, Mukherjee G, Kumar J, Kumar D, Kumar D, Sastri CV, de Visser SP. Keto-Enol Tautomerization Triggers an Electrophilic Aldehyde Deformylation Reaction by a Nonheme Manganese(III)-Peroxo Complex. J Am Chem Soc 2017; 139:18328-18338. [PMID: 29148746 DOI: 10.1021/jacs.7b10033] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes, including the biosynthesis of molecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants. In this work, we report a combined spectroscopy, kinetics and computational study on aldehyde deformylation by two side-on manganese(III)-peroxo complexes with bispidine ligands. Both manganese(III)-peroxo complexes are characterized by UV-vis and mass spectrometry techniques, and their reactivity patterns with aldehydes was investigated. We find a novel mechanism for the reaction that is initiated by a hydrogen atom abstraction reaction, which enables a keto-enol tautomerization in the substrate. This is an essential step in the mechanism that makes an electrophilic attack on the olefin bond possible as the attack on the aldehyde carbonyl is too high in energy. Kinetics studies determine a large kinetic isotope effect for the replacement of the transferring hydrogen atom by deuterium, while replacing the transferring hydrogen atom by a methyl group makes the substrate inactive and hence confirm the hypothesized mechanism. Our new mechanism is confirmed with density functional theory modeling on the full mechanism and rationalized through valence bond and thermochemical cycles. Our unprecedented new mechanism may have relevance to biological and biomimetic chemistry processes in general and gives insight into the reactivity patterns of metal-peroxo and metal-hydroperoxo intermediates in general.
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Affiliation(s)
- Fabián G Cantú Reinhard
- The Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Prasenjit Barman
- Department of Chemistry, Indian Institute of Technology Guwahati 781039, Assam, India
| | - Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati 781039, Assam, India
| | - Jitendra Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Deep Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Devesh Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati 781039, Assam, India
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
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9
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Benzing K, Comba P, Martin B, Pokrandt B, Keppler F. Nonheme Iron‐Oxo‐Catalyzed Methane Formation from Methyl Thioethers: Scope, Mechanism, and Relevance for Natural Systems. Chemistry 2017; 23:10465-10472. [DOI: 10.1002/chem.201701986] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Kathrin Benzing
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Peter Comba
- Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing (IWR)Heidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Bodo Martin
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Bianca Pokrandt
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Frank Keppler
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE)Heidelberg University Im Neuenheimer Feld 236 69120 Heidelberg Germany
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10
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Bhat D, Sharma N. Oxidative N-Dealkylation of Tertiary Amines with Tetraethylammonium Periodate Catalyzed by Metal Complexes. Aust J Chem 2017. [DOI: 10.1071/ch16200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The oxidative N-dealkylation of tertiary amines, N,N-dimethylaniline and N,N-diethylaniline, catalyzed by some sterically hindered FeIII complexes and tetraethylammonium periodate as oxidant gave the corresponding N-dealkylated and mono-oxygenated products in good yields. The presence of electronegative atoms on the catalyst complexes influenced the product yield. The presence of H-atom abstractor 2,6-di-tert-butyl-4-methylphenol did not influence product formation, thereby suggesting that the reaction proceeded predominantly via a one-electron transfer mechanism rather than via hydrogen abstraction. Tetraethylammonium periodate favoured oxygen transfer to the substrate.
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11
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Comba P, Pokrandt B, Wadepohl H. Oxidation of Cobalt(II) Bispidine Complexes with Dioxygen. Aust J Chem 2017. [DOI: 10.1071/ch16674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bispidine (3,7-diazabicyclo[3.3.1]nonane) ligands, derivatives of diazaadamantane, possess a very rigid backbone and have a high degree of pre-organization for cis-octahedral coordination geometries. Despite their rigidity, they exert a flexible coordination sphere, resulting in stable complexes with a variety of metal ions in various oxidation states. Due to the known high III/II redox potentials of their cobalt complexes, the CoII bispidine complexes are generally resistant to oxidation by dioxygen. Discussed in the present study are various CoII bispidine complexes with tetra- and pentadentate bispidines, with one of these complexes shown to be unstable under aerobic conditions. The decay process has been identified as an oxidative elimination of the 2-methylene pyridine substituent at one of the tertiary amine donors, resulting in picolinate, which is found coordinated to a CoIII product, where the dealkylated N-donor remains unprotonated. The mechanism of this interesting reaction has been studied, and details of the resulting structure of the product complex are discussed.
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12
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Agarwal DD, Bhat D. Substituted tetraphenyl porphyrin catalyzed oxidative N-dealkylation of tertiary amine using molecular oxygen. J PORPHYR PHTHALOCYA 2016. [DOI: 10.1142/s1088424616500607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Oxidative N-dealkylation of NN-dimethylaniline catalyzed by substituted tetraaryl porphyrin complexes of iron and manganese with molecular oxygen, gave a mixture of dealkylated, monooxygenated and dimerised compounds as products. Presence of substituents on the catalyst effects nature and yield of products formed. One electron transfer route [E T) predominated over H-atom abstraction [HAT] in most of the reactions.
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Affiliation(s)
- Dau. D. Agarwal
- SOS chemistry Jiwaji University, Gwalior (M.P) 474011, India
| | - Daisy Bhat
- R.D Foundation Group of Institutions NH-58, Ghaziabad (U.P) 201204, India
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13
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Grau M, Kyriacou A, Cabedo Martinez F, de Wispelaere IM, White AJP, Britovsek GJP. Unraveling the origins of catalyst degradation in non-heme iron-based alkane oxidation. Dalton Trans 2014; 43:17108-19. [DOI: 10.1039/c4dt02067g] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of iron(ii) complexes with tetradentate and pentadentate pyridyl amine ligands has been used for the oxidation of cyclohexane with hydrogen peroxide. Ligand degradation is observed under oxidising conditions via oxidative N-dealkylation.
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Affiliation(s)
- Michaela Grau
- Department of Chemistry
- Imperial College London
- London, UK
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14
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Legdali T, Roux A, Platas-Iglesias C, Camerel F, Nonat AM, Charbonnière LJ. Substitution-Assisted Stereochemical Control of Bispidone-Based Ligands. J Org Chem 2012; 77:11167-76. [DOI: 10.1021/jo302248c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tarik Legdali
- Laboratoire d’Ingénierie
Moléculaire Appliquée à l’Analyse, IPHC,
UMR 7178 CNRS/UdS, ECPM, Bât R1N0, 25 rue Becquerel, 67087
Strasbourg Cedex 02, France
| | - Amandine Roux
- Laboratoire d’Ingénierie
Moléculaire Appliquée à l’Analyse, IPHC,
UMR 7178 CNRS/UdS, ECPM, Bât R1N0, 25 rue Becquerel, 67087
Strasbourg Cedex 02, France
| | - Carlos Platas-Iglesias
- Departamento de Química
Fundamental, Universidade da Coruña, Campus da Zapateira- Rúa da Fraga 10, 15008, A Coruña,
Spain
| | - Franck Camerel
- Laboratoire Matière
Condensée
et Systèmes Électroactifs, Institut des Sciences Chimiques
de Rennes, UMR 6226, 263 Avenue du General Leclerc, CS 74205, 35042
Rennes Cedex, France
| | - Aline M. Nonat
- Laboratoire d’Ingénierie
Moléculaire Appliquée à l’Analyse, IPHC,
UMR 7178 CNRS/UdS, ECPM, Bât R1N0, 25 rue Becquerel, 67087
Strasbourg Cedex 02, France
| | - Loïc J. Charbonnière
- Laboratoire d’Ingénierie
Moléculaire Appliquée à l’Analyse, IPHC,
UMR 7178 CNRS/UdS, ECPM, Bât R1N0, 25 rue Becquerel, 67087
Strasbourg Cedex 02, France
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15
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Synthesis and molecular structure of the cobalt(ii) chloride complex with bis(α-pyridyl)-substituted bispidinoaza-14-crown-4. Russ Chem Bull 2012. [DOI: 10.1007/s11172-011-0328-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Latypova DR, Baibulatova NZ, Khisamutdinov RA, Murinov YI, Dokichev VA. Complex formation of copper(II) and palladium(II) with L,L-3,7-bis[2-(4-hydroxyphenyl)-1-(methoxycarbonyl)ethyl]-1,5-di(ethoxycarbonyl)-3,7-diazabicyclo[3.3.1]nonan-9-one. RUSS J INORG CHEM+ 2011. [DOI: 10.1134/s0036023611060155] [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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17
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Comba P, Wadepohl H, Wiesner S. Optimization of the Efficiency of Oxidation Catalysts Based on Iron Bispidine Complexes. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201100212] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Vad MS, Nielsen A, Lennartson A, Bond AD, McGrady JE, McKenzie CJ. Switching on oxygen activation by cobalt complexes of pentadentate ligands. Dalton Trans 2011; 40:10698-707. [DOI: 10.1039/c1dt10594a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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19
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Roberts KM, Jones JP. Anilinic N-oxides support cytochrome P450-mediated N-dealkylation through hydrogen-atom transfer. Chemistry 2010; 16:8096-107. [PMID: 20521282 DOI: 10.1002/chem.201000185] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mechanism of N-dealkylation mediated by cytochrome P450 (P450) has long been studied and argued as either a single electron transfer (SET) or a hydrogen atom transfer (HAT) from the amine to the oxidant of the P450, the reputed iron-oxene. In our study, tertiary anilinic N-oxides were used as oxygen surrogates to directly generate a P450-mediated oxidant that is capable of N-dealkylating the dimethylaniline derived from oxygen donation. These surrogates were employed to probe the generated reactive oxygen species and the subsequent mechanism of N-dealkylation to distinguish between the HAT and SET mechanisms. In addition to the expected N-demethylation of the product aniline, 2,3,4,5,6-pentafluoro-N,N-dimethylaniline N-oxide (PFDMAO) was found to be capable of N-dealkylating both N,N-dimethylaniline (DMA) and N-cyclopropyl-N-methylaniline (CPMA). Rate comparisons of the N-demethylation of DMA supported by PFDMAO show a 27-fold faster rate than when supported by N,N-dimethylaniline N-oxide (DMAO). Whereas intermolecular kinetic isotope effects were masked, intramolecular measurements showed values reflective of those seen previously in DMAO- and the native NADPH/O(2)-supported systems (2.33 and 2.8 for the N-demethylation of PFDMA and DMA from the PFDMAO system, respectively). PFDMAO-supported N-dealkylation of CPMA led to the ring-intact product N-cyclopropylaniline (CPA), similar to that seen with the native system. The formation of CPA argues against a SET mechanism in favor of a P450-like HAT mechanism. We suggest that the similarity of KIEs, in addition to the formation of the ring-intact CPA, argues for a similar mechanism of Compound I (Cpd I) formation followed by HAT for N-dealkylation by the native and N-oxide-supported systems and demonstrate the ability of the N-oxide-generated oxidant to act as an accurate mimic of the native P450 oxidant.
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Affiliation(s)
- Kenneth M Roberts
- Department of Chemistry, Washington State University, PO BOX 644630, Pullman, WA 99164-4630, USA
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20
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Juran S, Walther M, Stephan H, Bergmann R, Steinbach J, Kraus W, Emmerling F, Comba P. Hexadentate Bispidine Derivatives as Versatile Bifunctional Chelate Agents for Copper(II) Radioisotopes. Bioconjug Chem 2009; 20:347-59. [DOI: 10.1021/bc800461e] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stefanie Juran
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Martin Walther
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Holger Stephan
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Ralf Bergmann
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Jörg Steinbach
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Werner Kraus
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Franziska Emmerling
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Peter Comba
- Forschungszentrum Dresden-Rossendorf, Institute of Radiopharmacy, PF 510119, D-01314 Dresden, Germany, Bundesanstalt für Materialforschung and -prüfung, Richard-Willstätter-Strasse 11, D-12489, Berlin, Germany, and Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
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Comba P, Kerscher M, Lawrance G, Martin B, Wadepohl H, Wunderlich S. Stabile fünf- und sechsfach koordinierte Cobalt(III)-Komplexe mit einem fünfzähnigen Bispidinliganden. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Comba P, Kerscher M, Lawrance G, Martin B, Wadepohl H, Wunderlich S. Stable Five- and Six-Coordinate Cobalt(III) Complexes with a Pentadentate Bispidine Ligand. Angew Chem Int Ed Engl 2008; 47:4740-3. [DOI: 10.1002/anie.200800515] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Comba P, Kerscher M, Schiek W. Bispidine Coordination Chemistry. PROGRESS IN INORGANIC CHEMISTRY 2008. [DOI: 10.1002/9780470144428.ch9] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ingle GK, Makowska‐Grzyka MM, Arif AM, Berreau LM. Divalent Nickel, Cobalt and Iron Complexes of an Amide‐Appended N
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Ligand: Synthesis, Characterization and Reactivity with Hydroxide Anion. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700582] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Gajendrasingh K. Ingle
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322‐0300, USA, Fax: +1‐435‐797‐3390
| | - Magdalena M. Makowska‐Grzyka
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322‐0300, USA, Fax: +1‐435‐797‐3390
| | - Atta M. Arif
- Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, UT, 84112‐0850, USA
| | - Lisa M. Berreau
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322‐0300, USA, Fax: +1‐435‐797‐3390
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