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Takeyama T, Shimazaki Y. Diversity of oxidation state in copper complexes with phenolate ligands. Dalton Trans 2024; 53:3911-3929. [PMID: 38319292 DOI: 10.1039/d3dt04230h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The phenoxyl radical binding copper complexes have been widely developed and their detailed geometric and electronic structures have been clarified. While many one-electron oxidized CuII-phenolate complexes have been reported previously, recent studies of the Cu-phenolate complexes proceed toward elucidation of the complexes with other oxidation states, such as the phenoxyl radical binding CuI complexes and CuIV-phenolate complexes in the formal oxidation state. This Perspective focuses on new aspects of the properties and reactivities of various Cu-phenolate and Cu-phenoxyl radical complexes with emphasis on the relationship between geometric and electronic structures.
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Affiliation(s)
- Tomoyuki Takeyama
- Department of Applied Chemistry, Sanyo-Onoda City University, 1-1-1, Daigakudori, Sanyo-Onoda, 756-0884 Yamaguchi, Japan.
| | - Yuichi Shimazaki
- College of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan.
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2
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Fernholz C, Bodi A, Hemberger P. Threshold Photoelectron Spectrum of the Phenoxy Radical. J Phys Chem A 2022; 126:9022-9030. [DOI: 10.1021/acs.jpca.2c06670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christin Fernholz
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
| | - Andras Bodi
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
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3
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Redox-active ligands: Recent advances towards their incorporation into coordination polymers and metal-organic frameworks. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213891] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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4
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Proniewicz E, Małuch I, Kudelski A, Prahl A. Adsorption of (Phe-h 5)/(Phe-d 5)-substituted peptides from neurotensin family on the nanostructured surfaces of Ag and Cu: SERS studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 242:118748. [PMID: 32721658 DOI: 10.1016/j.saa.2020.118748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/09/2020] [Accepted: 07/15/2020] [Indexed: 05/25/2023]
Abstract
This work describes an application of Raman (RS) and surface-enhanced Raman scattering (SERS) to characterize the selective adsorption of two peptides belonging to the neurotensin family peptides, such as kinetensin (KN) and xenopsin-related peptide 2 (XP-2) that are known to stimulate the growth of human tumors. To perform a reliable analysis of SERS spectra, the L-Phe residue (at position 8 or 1 in the amino acid sequence of these peptides) was replaced with L-Phe-d5 (five protons of L-phenylalanine ring substituted by deuterium). Native and (Phe-d5)-isotopically labeled peptides were deposited on electrochemically nanostructured surfaces of Ag (AgORC) and Cu (CuORC) from an aqueous solution (H2O). To determine the share of amide bonds in the interaction with the metallic substrate, SERS spectra of peptides adsorbed on AgORC from heavy water (D2O) were measured. Also, to determine the effect of the C-end on the SERS spectrum, measurements were made for the KN analog in which the C-terminal L-leucine was removed ([desLeu9]KN). Based on the analyses of the spectral profiles, in the spectral range of 600-1650 cm-1, specific conclusions have been drawn regarding specific aromatic ring···metal interactions and changes in the interaction during substrate change.
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Affiliation(s)
- E Proniewicz
- Faculty of Foundry Engineering, AGH University of Science and Technology, 30-059 Krakow, Poland.
| | - I Małuch
- Department of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland
| | - A Kudelski
- Faculty of Chemistry, University of Warsaw, ul. Pasteur 1, 02-093 Warsaw, Poland
| | - A Prahl
- Department of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland
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5
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Proniewicz E, Tąta A, Wójcik A, Starowicz M, Pacek J, Molenda M. SERS activity and spectroscopic properties of Zn and ZnO nanostructures obtained by electrochemical and green chemistry methods for applications in biology and medicine. Phys Chem Chem Phys 2020; 22:28100-28114. [DOI: 10.1039/d0cp03517c] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work evaluates the ability of homogeneous, stable, and pure zinc oxide nanoparticles (ZnONPs-GS) synthesized by “green chemistry” for the selective detection of four neurotransmitters present in body fluids and promotion of the SERS effect.
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Affiliation(s)
- Edyta Proniewicz
- Faculty of Foundry Engineering
- AGH University of Science and Technology
- 30-059 Krakow
- Poland
| | - Agnieszka Tąta
- Faculty of Foundry Engineering
- AGH University of Science and Technology
- 30-059 Krakow
- Poland
| | - Anna Wójcik
- Institute of Metallurgy and Materials Science of Polish Academy of Science
- 30-059 Krakow
- Poland
| | - Maria Starowicz
- Faculty of Foundry Engineering
- AGH University of Science and Technology
- 30-059 Krakow
- Poland
| | - Joanna Pacek
- Faculty of Chemistry
- Jagiellonian University
- 30-387 Krakow
- Poland
| | - Marcin Molenda
- Faculty of Chemistry
- Jagiellonian University
- 30-387 Krakow
- Poland
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6
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Keck M, Hoof S, Herwig C, Vigalok A, Limberg C. Oxygen-Depleted Calixarenes as Ligands for Molecular Models of Galactose Oxidase. Chemistry 2019; 25:13285-13289. [PMID: 31441974 PMCID: PMC6857004 DOI: 10.1002/chem.201903820] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Indexed: 11/10/2022]
Abstract
A calix[4]arene ligand, in which two of the phenol functions are replaced by pyrazole units has been employed to mimic the His2 -Tyr2 (His: histidine, Tyr: tyrosine) ligand sphere within the active site of the galactose oxidase (GO). The calixarene backbone forces the corresponding copper(II) complex into a see-saw-type structure, which is hitherto unprecedented in GO modelling chemistry. It undergoes a one-electron oxidation that is centered at the phenolate donor leading to a copper-coordinated phenoxyl radical like in the GO. Accordingly, the complex was tested as a functional model and indeed proved capable of oxidizing benzyl alcohol to the respective aldehyde using two phenoxyl-radical equivalents as oxidants. Finally, the results show that the calixarene platform can be utilized to arrange donor functions to biomimetic binding pockets that allow for the creation of novel types of model compounds.
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Affiliation(s)
- Matthias Keck
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
| | - Santina Hoof
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
| | - Christian Herwig
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
| | - Arkadi Vigalok
- School of ChemistryTel Aviv University1 Ramat Aviv69978Tel AvivIsrael
| | - Christian Limberg
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Strasse 212489BerlinGermany
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7
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Hernandez-Castillo AO, Abeysekera C, Stanton JF, Zwier TS. Structural Characterization of Phenoxy Radical with Mass-Correlated Broadband Microwave Spectroscopy. J Phys Chem Lett 2019; 10:2919-2923. [PMID: 31084013 DOI: 10.1021/acs.jpclett.9b00837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A combination of broadband microwave spectroscopy and VUV photoionization time-of-flight mass spectra has been used to record rotational spectra of the prototypical phenoxy radical, its per-deuterated isotopomers, and the full set of singly 13C-substituted analogues. Rotational parameters associated with the fits to the full set of isotopomers produce a highly accurate r0 structure for the phenoxy radical. High-level ab initio calculations accurately reproduce the rotational constants and spin-rotation parameters. The structure of the phenoxy radical is distinctly quinoidal, with delocalization of the unpaired electron spin density on the oxygen and phenyl ring. The fitted Fermi contact terms for the 13C atoms reflect a weighting of resonance structures that is 27% on the O atom, 21.5% on each of the two ortho C's, and 30% on the para C, providing a quantitative measure of its sites for subsequent reactions that will control its abundances in combustion and atmospheric environments.
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Affiliation(s)
- A O Hernandez-Castillo
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907-2084 , United States
| | - Chamara Abeysekera
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907-2084 , United States
| | - John F Stanton
- Department of Chemistry , University of Florida , P.O. Box 117200, Gainesville , Florida 32611 , United States
| | - Timothy S Zwier
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907-2084 , United States
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8
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Chiang L, Wasinger EC, Shimazaki Y, Young V, Storr T, Stack TDP. Electronic Structure and Reactivity Studies of a Nonsymmetric One-Electron Oxidized Cu II Bis-phenoxide Complex. Inorganica Chim Acta 2018; 481:151-158. [PMID: 30581226 PMCID: PMC6301013 DOI: 10.1016/j.ica.2017.09.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The tetradentate mixed imino/amino phenoxide ligand (N-(3,5-di-tert-butylsalicylidene)-N'-(2-hydroxyl-3,5-di-tert-butylbenzyl))-trans-1,2-cyclohexanediamine (salalen) was complexed with CuII, and the resulting Cu complex (2) was characterized by a number of experimental techniques and theoretical calculations. Two quasi-reversible redox processes for 2, as observed by cyclic voltammetry, demonstrated the potential stability of oxidized forms, and also the increased electron-donating ability of the salalen ligand in comparison to the salen analogue. The electronic structure of the one-electron oxidized [2]+ was then studied in detail, and Cu K-edge X-ray Absorption Spectroscopy (XAS) measurements confirmed a CuII-phenoxyl radical complex in solution. Subsequent resonance Raman (rR) and variable temperature 1H NMR studies, coupled with theoretical calculations, showed that [2• ]+ is a triplet (S = 1) CuII-phenoxyl radical species, with localization of the radical on the more electron-rich aminophenoxide. Attempted isolation of X-ray quality crystals of [2• ]+ afforded [2H]+, with a protonated phenol bonded to CuII, and an additional H-bonding interaction with the SbF6 - counterion. Stoichiometric reaction of dilute solutions of [2• ]+ with benzyl alcohol showed that the complex reacted in a similar manner as the oxidized CuII-salen analogue, and does not exhibit a substrate-binding pre-equilibrium as observed for the oxidized bisaminophenoxide CuII-salan derivative.
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Affiliation(s)
- Linus Chiang
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Erik C Wasinger
- Department of Chemistry and Biochemistry, California State University, Chico, CA 95928, USA
| | - Yuichi Shimazaki
- College of Science, Ibaraki University. Bunkyo, Mito, 310-8512, Japan
| | - Victor Young
- Department of Chemistry, The University of Minnesota, Minneapolis, MN 55455, USA
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - T Daniel P Stack
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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9
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Calcium, conformational selection, and redox-active tyrosine YZ in the photosynthetic oxygen-evolving cluster. Proc Natl Acad Sci U S A 2018; 115:5658-5663. [PMID: 29752381 DOI: 10.1073/pnas.1800758115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In Photosystem II (PSII), YZ (Tyr161D1) participates in radical transfer between the chlorophyll donor and the Mn4CaO5 cluster. Under flashing illumination, the metal cluster cycles among five Sn states, and oxygen is evolved from water. The essential YZ is transiently oxidized and reduced on each flash in a proton-coupled electron transfer (PCET) reaction. Calcium is required for function. Of reconstituted divalent ions, only strontium restores oxygen evolution. YZ is predicted to hydrogen bond to calcium-bound water and to His190D1 in PSII structures. Here, we report a vibrational spectroscopic study of YZ radical and singlet in the presence of the metal cluster. The S2 state is trapped by illumination at 190 K; flash illumination then generates the S2YZ radical. Using reaction-induced FTIR spectroscopy and divalent ion depletion/substitution, we identify calcium-sensitive tyrosyl radical and tyrosine singlet bands in the S2 state. In calcium-containing PSII, two CO stretching bands are detected at 1,503 and 1,478 cm-1 These bands are assigned to two different radical conformers in calcium-containing PSII. At pH 6.0, the 1,503-cm-1 band shifts to 1,507 cm-1 in strontium-containing PSII, and the band is reduced in intensity in calcium-depleted PSII. These effects are consistent with a hydrogen-bonding interaction between the calcium site and one conformer of radical YZ. Analysis of the amide I region indicates that calcium selects for a PCET reaction in a subset of the YZ conformers, which are trapped in the S2 state. These results support the interpretation that YZ undergoes a redox-coupled conformational change, which is calcium dependent.
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10
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Mondal D, Kundu S, Majee MC, Rana A, Endo A, Chaudhury M. Ligand-Induced Tuning of the Oxidase Activity of μ-Hydroxidodimanganese(III) Complexes Using 3,5-Di-tert-butylcatechol as the Substrate: Isolation and Characterization of Products Involving an Oxidized Dioxolene Moiety. Inorg Chem 2017; 56:9448-9460. [DOI: 10.1021/acs.inorgchem.7b00147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dhrubajyoti Mondal
- Department of Inorganic
Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Sanchita Kundu
- Department of Inorganic
Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Mithun Chandra Majee
- Department of Inorganic
Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Atanu Rana
- Department of Inorganic
Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Akira Endo
- Department
of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Muktimoy Chaudhury
- Department of Inorganic
Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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11
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Unjaroen D, Swart M, Browne WR. Electrochemical Polymerization of Iron(III) Polypyridyl Complexes through C–C Coupling of Redox Non-innocent Phenolato Ligands. Inorg Chem 2016; 56:470-479. [DOI: 10.1021/acs.inorgchem.6b02378] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Duenpen Unjaroen
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi (IQCC),
Departament de Química, Universitat de Girona, Campus Montilivi, 17003 Girona, Catalonia, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Wesley R. Browne
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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12
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Chiang L, Clarke RM, Herasymchuk K, Sutherland M, Prosser KE, Shimazaki Y, Storr T. Electronic Structure Evaluation of an Oxidized Tris(methoxy)-Substituted Ni Salen Complex. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201501144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Barry BA. Reaction dynamics and proton coupled electron transfer: studies of tyrosine-based charge transfer in natural and biomimetic systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:46-54. [PMID: 25260243 DOI: 10.1016/j.bbabio.2014.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 08/27/2014] [Accepted: 09/10/2014] [Indexed: 11/25/2022]
Abstract
In bioenergetic reactions, electrons are transferred long distances via a hopping mechanism. In photosynthesis and DNA synthesis, the aromatic amino acid residue, tyrosine, functions as an intermediate that is transiently oxidized and reduced during long distance electron transfer. At physiological pH values, oxidation of tyrosine is associated with a deprotonation of the phenolic oxygen, giving rise to a proton coupled electron transfer (PCET) reaction. Tyrosine-based PCET reactions are important in photosystem II, which carries out the light-induced oxidation of water, and in ribonucleotide reductase, which reduces ribonucleotides to form deoxynucleotides. Photosystem II contains two redox-active tyrosines, YD (Y160 in the D2 polypeptide) and YZ (Y161 in the D1 polypeptide). YD forms a light-induced stable radical, while YZ functions as an essential charge relay, oxidizing the catalytic Mn₄CaO₅ cluster on each of four photo-oxidation reactions. In Escherichia coli class 1a RNR, the β2 subunit contains the radical initiator, Y122O•, which is reversibly reduced and oxidized in long range electron transfer with the α2 subunit. In the isolated E. coli β2 subunit, Y122O• is a stable radical, but Y122O• is activated for rapid PCET in an α2β2 substrate/effector complex. Recent results concerning the structure and function of YD, YZ, and Y122 are reviewed here. Comparison is made to recent results derived from bioengineered proteins and biomimetic compounds, in which tyrosine-based charge transfer mechanisms have been investigated. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.
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Affiliation(s)
- Bridgette A Barry
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA; Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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14
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Chiang L, Savard D, Shimazaki Y, Thomas F, Storr T. FeIII Bipyrrolidine Phenoxide Complexes and Their Oxidized Analogues. Inorg Chem 2014; 53:5810-9. [DOI: 10.1021/ic500663x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Linus Chiang
- Department of Chemistry, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
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15
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Rakshit R, Ghorai S, Biswas S, Mukherjee C. Effect of ligand substituent coordination on the geometry and the electronic structure of Cu(II)-diradical complexes. Inorg Chem 2014; 53:3333-7. [PMID: 24654914 DOI: 10.1021/ic402612v] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two organic moieties, known as ligands, having -OMe and -SePh as the ortho substituent attached to the aniline moiety of the parent 2-anilino-4,6-di-tert-butylphenol ligand, were synthesized. The ligands reacted with CuCl2·2H2O in a 2:1 ratio in CH3CN in the presence of Et3N and provided the corresponding mononuclear Cu(II)-diradical complexes 1 (-OMe) and 2 (-SePh). Complex 1 was square planar, while complex 2 was in distorted square planar geometry due to the secondary coordination between the Se atom and the central Cu(II) center. Both complexes were comprised of multi-paramagnetic centers and exhibited an St = 1/2 ground state as established by variable-temperature magnetic susceptibility measurements. X-band electron paramagnetic resonance measurements indicated the presence of an unpaired electron at the Cu(II) center in complex 1 and at the ligand center (π-radical) in complex 2. The extent of the secondary interaction was found to be dependent on the "softness" of the donor atom belonging to the ortho substituent.
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Affiliation(s)
- Richa Rakshit
- Department of Chemistry, Indian Institute of Technology , Guwahati 781039, Assam, India
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16
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Nizovtsev AV, Scheurer A, Kosog B, Heinemann FW, Meyer K. Synthesis of Differently Substituted tacn-Based Ligands: Towards the Control of Solubility and Electronic and Steric Properties of Uranium Coordination Complexes. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201201549] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Asami K, Tsukidate K, Iwatsuki S, Tani F, Karasawa S, Chiang L, Storr T, Thomas F, Shimazaki Y. New Insights into the Electronic Structure and Reactivity of One-Electron Oxidized Copper(II)-(Disalicylidene)diamine Complexes. Inorg Chem 2012; 51:12450-61. [DOI: 10.1021/ic3018503] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kazutaka Asami
- College of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Kazuaki Tsukidate
- College of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
| | - Satoshi Iwatsuki
- Department of Chemistry, Konan University, Higashinada-ku, Kobe 658-8501, Japan
| | - Fumito Tani
- Institute for Materials Chemistry
and Engineering, Kyushu University, Higashi-ku,
Fukuoka 812-8581, Japan
| | - Satoru Karasawa
- Graduate School of Pharmaceutical
Sciences, Kyushu University, Higashi-ku,
Fukuoka 812-8582, Japan
| | - Linus Chiang
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia,
Canada
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia,
Canada
| | - Fabrice Thomas
- Département
de Chimie
Moléculaire-Chimie Inorganique Redox Biomimétique (CIRE)
- UMR CNRS 5250, Université Joseph Fourier, B. P. 53, 38041 Grenoble cedex 9, France
| | - Yuichi Shimazaki
- College of Science, Ibaraki University, Bunkyo, Mito 310-8512, Japan
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18
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Allard MM, Xavier FR, Heeg MJ, Schlegel HB, Verani CN. Sequential Phenolate Oxidations in Octahedral Cobalt(III) Complexes with [N2O3] Ligands. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200171] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Chiang L, Kochem A, Jarjayes O, Dunn TJ, Vezin H, Sakaguchi M, Ogura T, Orio M, Shimazaki Y, Thomas F, Storr T. Radical Localization in a Series of Symmetric NiIIComplexes with Oxidized Salen Ligands. Chemistry 2012; 18:14117-27. [DOI: 10.1002/chem.201201410] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Indexed: 11/12/2022]
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20
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Storr T, Verma P, Shimazaki Y, Wasinger EC, Stack TDP. Ligand radical localization in a nonsymmetric one-electron oxidized Ni(II) bis-phenoxide complex. Chemistry 2010; 16:8980-3. [PMID: 20645357 PMCID: PMC3480210 DOI: 10.1002/chem.201001401] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Tim Storr
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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21
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Cheng L, Wang J, Wang M, Wu Z. Theoretical studies on the reaction mechanism of oxidation of primary alcohols by Zn/Cu(ii)-phenoxyl radical catalyst. Dalton Trans 2009:3286-97. [DOI: 10.1039/b817985a] [Citation(s) in RCA: 12] [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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22
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Storr T, Verma P, Pratt RC, Wasinger EC, Shimazaki Y, Stack TDP. Defining the electronic and geometric structure of one-electron oxidized copper-bis-phenoxide complexes. J Am Chem Soc 2008; 130:15448-59. [PMID: 18939830 PMCID: PMC2663632 DOI: 10.1021/ja804339m] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The geometric and electronic structure of an oxidized Cu complex ([CuSal](+); Sal = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV-vis-NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal](+) (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal](+), affording exclusively a Cu(III) species in the solid state (4-300 K). Variable-temperature solution studies suggest that [CuSal](+) exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal(*)](+) (S = 1) and the high-valent metal form [Cu(III)Sal](+) (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine-bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSal(red)](+) (Sal(red) = N,N'-bis(3,5-di- tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)-ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu-bis-phenoxide complexes.
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Strautmann JBH, George SD, Bothe E, Bill E, Weyhermüller T, Stammler A, Bögge H, Glaser T. Molecular and Electronic Structures of Mononuclear Iron Complexes Using Strongly Electron-Donating Ligands and their Oxidized Forms. Inorg Chem 2008; 47:6804-24. [DOI: 10.1021/ic800335t] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Julia B. H. Strautmann
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Serena DeBeer George
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Eberhard Bothe
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Eckhard Bill
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Thomas Weyhermüller
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Anja Stammler
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Hartmut Bögge
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
| | - Thorsten Glaser
- Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany, Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, and Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim, Germany
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Milko P, Roithová J, Tsierkezos N, Schröder D. The C-O stretch as an unprecedently large spectral marker for the electron transfer between Copper(II) and a phenolate anion. J Am Chem Soc 2008; 130:7186-7. [PMID: 18479087 DOI: 10.1021/ja801079r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An unprecedented red shift of more than 200 cm(-1) in the vibrational frequency of the C-O bond in the [Cu(PhO)Ln]+ complex (PhO = phenoxy), dependent on the number n of additional ligands L, is reported. Upon change of n from 1 to 2, the spin density is shifted from the aromatic ring to the oxygen and copper atoms, which is reflected in the bond order and thus vibrational frequency of the C-O bond.
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Affiliation(s)
- Petr Milko
- Faculty of Science, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic
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Kurahashi T, Kikuchi A, Tosha T, Shiro Y, Kitagawa T, Fujii H. Transient Intermediates from Mn(salen) with Sterically Hindered Mesityl Groups: Interconversion between MnIV-Phenolate and MnIII-Phenoxyl Radicals as an Origin for Unique Reactivity. Inorg Chem 2008; 47:1674-86. [DOI: 10.1021/ic702061y] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takuya Kurahashi
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
| | - Akihiro Kikuchi
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
| | - Takehiko Tosha
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
| | - Yoshitsugu Shiro
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
| | - Teizo Kitagawa
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hiroshi Fujii
- Institute for Molecular Science & Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan, and RIKEN SPring-8 Center, Harima Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
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Nagano Y, Liu JG, Naruta Y, Ikoma T, Tero-Kubota S, Kitagawa T. Characterization of the phenoxyl radical in model complexes for the Cu(B) site of cytochrome c oxidase: steady-state and transient absorption measurements, UV resonance raman spectroscopy, EPR spectroscopy, and DFT calculations for M-BIAIP. J Am Chem Soc 2007; 128:14560-70. [PMID: 17090040 DOI: 10.1021/ja061507y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Physicochemical properties of the covalently cross-linked tyrosine-histidine-Cu(B) (Tyr-His-Cu(B)) unit, which is a minimal model complex [M(II)-BIAIPBr]Br (M = Cu(II), Zn(II)) for the Cu(B) site of cytochrome c oxidase, were investigated with steady-state and transient absorption measurements, UV resonance Raman (UVRR) spectroscopy, X-band continuous-wave electron paramagnetic resonance (EPR) spectroscopy, and DFT calculations. The pH dependency of the absorption spectra reveals that the pK(a) of the phenolic hydroxyl is ca. 10 for the Cu(II) model complex (Cu(II)-BIAIP) in the ground state, which is similar to that of p-cresol (tyrosine), contrary to expectations. The bond between Cu(II) and nitrogen of cross-linked imidazole cleaves at pH 4.9. We have successfully obtained UVRR spectra of the phenoxyl radical form of BIAIPs and have assigned bands based on the previously reported isotope shifts of Im-Ph (2-(1-imidazoyl)-4-methylphenol) (Aki, M.; Ogura, T.; Naruta, Y.; Le, T. H.; Sato, T.; Kitagawa, T. J. Phys. Chem. A 2002, 106, 3436-3444) in combination with DFT calculations. The upshifts of the phenoxyl vibrational frequencies for 8a (C-C stretching), 7a' (C-O stretching), and 19a, and the Raman-intensity enhancements of 19b, 8b, and 14 modes indicate that UVRR spectra are highly sensitive to imidazole-phenol covalent linkage. Both transient absorption measurements and EPR spectra suggest that the Tyr-His-Cu(B) unit has only a minor effect on the electronic structure of the phenoxyl radical form, although our experimental results appear to indicate that the cross-linked Tyr radical exhibits no EPR. The role of the Tyr-His-Cu(B) unit in the enzyme is discussed in terms of the obtained spectroscopic parameters of the model complex.
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Affiliation(s)
- Yasutomo Nagano
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Science, Okazaki 444-8787, Japan
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He Y, Gahlmann A, Feenstra JS, Park ST, Zewail AH. Ultrafast Electron Diffraction: Structural Dynamics of Molecular Rearrangement in the NO Release from Nitrobenzene. Chem Asian J 2006; 1:56-63. [PMID: 17441038 DOI: 10.1002/asia.200600107] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nitro compounds release NO, NO2, and other species, but neither the structures during the reactions nor the time scales are known. Ultrafast electron diffraction (UED) allowed the study of the NO release from nitrobenzene, and the molecular pathways and the structures of the transient species were identified. It was observed, in contrast to previous inferences, that nitric oxide and phenoxyl radicals are formed dominantly and that the time scale of formation is 8.8+/-2.2 ps. The structure of the phenoxyl radical was determined for the first time, and found to be quinoid-like. The mechanism proposed involves a repulsive triplet state, following intramolecular rearrangement. This efficient generation of NO may have important implications for the control of by-products in drug delivery and other applications.
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Affiliation(s)
- Yonggang He
- Laboratory for Molecular Science and Physical Biology Center for Ultrafast Science and Technology, California Institute of Technology, Pasadena, CA 91125, USA
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29
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Schatzschneider U, Metzler-Nolte N. Neue Wirkmechanismen in der medizinischen Organometallchemie. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200504604] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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30
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Schatzschneider U, Metzler-Nolte N. New Principles in Medicinal Organometallic Chemistry. Angew Chem Int Ed Engl 2006; 45:1504-7. [PMID: 16453361 DOI: 10.1002/anie.200504604] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ulrich Schatzschneider
- Institut für Pharmazie und Molekulare Biotechnologie, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.
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31
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Barsberg S, Matousek P, Towrie M, Jørgensen H, Felby C. Lignin radicals in the plant cell wall probed by Kerr-gated resonance Raman spectroscopy. Biophys J 2006; 90:2978-86. [PMID: 16443659 PMCID: PMC1414548 DOI: 10.1529/biophysj.105.070391] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lignin radicals are crucial intermediates for lignin biosynthesis in the cell wall of vascular plants. In this work they were for the first time, to our knowledge, selectively observed in wood cell walls by laser-based Kerr-gated resonance Raman spectroscopy, and the observations were supported by density functional theory prediction of their vibrational properties. For dry wood cells a lignin radical Raman band is observed at 1,570 cm(-1) irrespective of species. For wet beech cells they were generated in situ and observed at 1,606 cm(-1). DFT/B3LYP/6-31+G(d) modeling results support that in beech they are formed from syringyl (S) phenolic moieties and in spruce from guaiacyl (G) phenolic moieties. The observed lignin radical band is predicted as G is approximately 1,597 cm(-1) and S is approximately 1,599 cm(-1), respectively, and is assigned the (Wilson notation) nu(8a) phenyl ring mode. The RR band probes lignin radical properties, e.g., spin density distribution, and these respond to charge polarization or hydrogen bonding to proximate water molecules. These observations can be crucial for an understanding of the factors that control cell wall structure during biosynthesis of vascular plants and demonstrate the unique potential of RR spectroscopy of lignin radicals.
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Affiliation(s)
- Søren Barsberg
- Danish Centre for Forest, Landscape and Planning, The Royal Veterinary and Agricultural University, DK-2630 Taastrup, Denmark.
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32
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Patra S, Sarkar B, Maji S, Fiedler J, Urbanos FA, Jimenez-Aparicio R, Kaim W, Lahiri GK. Controlling Metal–Ligand–Metal Oxidation State Combinations by Ancillary Ligand (L) Variation in the Redox Systems [L2Ru(μ-boptz)RuL2]n, boptz=3,6-bis(2-oxidophenyl)-1,2,4,5-tetrazine, and L=acetylacetonate, 2,2′-bipyridine, or 2-phenylazopyridine. Chemistry 2006; 12:489-98. [PMID: 16134203 DOI: 10.1002/chem.200500295] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The new compounds [(acac)2Ru(mu-boptz)Ru(acac)2] (1), [(bpy)2Ru(mu-boptz)Ru(bpy)2](ClO4)2 (2-(ClO4)2), and [(pap)2Ru(mu-boptz)Ru(pap)2](ClO4)2 (3-(ClO4)2) were obtained from 3,6-bis(2-hydroxyphenyl)-1,2,4,5-tetrazine (H2boptz), the crystal structure analysis of which is reported. Compound 1 contains two antiferromagnetically coupled (J = -36.7 cm(-1)) Ru(III) centers. We have investigated the role of both the donor and acceptor functions containing the boptz2- bridging ligand in combination with the electronically different ancillary ligands (donating acac-, moderately pi-accepting bpy, and strongly pi-accepting pap; acac = acetylacetonate, bpy = 2,2'-bipyridine pap = 2-phenylazopyridine) by using cyclic voltammetry, spectroelectrochemistry and electron paramagnetic resonance (EPR) spectroscopy for several in situ accessible redox states. We found that metal-ligand-metal oxidation state combinations remain invariant to ancillary ligand change in some instances; however, three isoelectronic paramagnetic cores Ru(mu-boptz)Ru showed remarkable differences. The excellent tolerance of the bpy co-ligand for both Ru(III) and Ru(II) is demonstrated by the adoption of the mixed-valent form in [L2Ru(mu-boptz)RuL2]3+, L = bpy, whereas the corresponding system with pap stabilizes the Ru(II) states to yield a phenoxyl radical ligand and the compound with L = acac- contains two Ru(III) centers connected by a tetrazine radical-anion bridge.
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Affiliation(s)
- Srikanta Patra
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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33
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Zueva E, Walton PH, McGrady JE. Catalytic alcohol oxidation by an unsymmetrical 5-coordinate copper complex: electronic structure and mechanism. Dalton Trans 2006:159-67. [PMID: 16357972 DOI: 10.1039/b512298h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory reveals the detailed mechanism of alcohol oxidation by a model copper complex, Cu(II)L, L = cis-1-(3',5'-dimethoxy-benzylideneamino)-3,5-[2-hydroxy-(3',5'-di-tert-butyl)benzylideneimino]cyclohexane. Despite the obvious structural and functional parallels between the title compound and the enzyme galactose oxidase, the details of the catalytic pathway are fundamentally different. In the enzyme, coordination of the substrate produces an active form containing a Cu(II) centre and a tyrosyl radical, the latter being responsible for the abstraction of hydrogen from the substrate. In the model system, in marked contrast, the active form contains a Cu(II) centre, but the ligand radical character is localised on the substrate (alcoholate) oxygen, rather than the phenolate ligand. The result is a significantly higher barrier to hydrogen-atom abstraction compared to the enzyme itself. The origin of these significant differences is traced to the rigid nature of the pentadentate ligand, which resists changes in coordination number during the catalytic cycle.
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Affiliation(s)
- Ekaterina Zueva
- Department of Inorganic Chemistry, Kazan State Technological University, 68 Karl Marx St., Kazan 420015, Russia.
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Romba J, Kuppert D, Morgenstern B, Neis C, Steinhauser S, Weyhermüller T, Hegetschweiler K. The Coordination Chemistry of 1,4-Diazepan-6-amine. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200500690] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bu Y, Cukier RI. Structural Character and Energetics of Tyrosyl Radical Formation by Electron/Proton Transfers of a Covalently Linked Histidine-Tyrosine: A Model for Cytochrome c Oxidase. J Phys Chem B 2005; 109:22013-26. [PMID: 16853859 DOI: 10.1021/jp053046t] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural, energetic, and electronic and IR spectroscopic properties for a model of the cross-linked histidine-tyrosine (His-Tyr) residues as found in cytochrome c oxidase (CcO) are investigated by ab initio methods. The formation of a His-Tyr radical is studied by two paths: proton release followed by electron release and vice versa. The energetics for the proton/electron releases of the Tyr depend modestly on the cross-linked His substituent and, more sensitively, on the charge of the cation attached to the imino N site of the His residue. Protonation of the imino N site significantly increases the electron ionization potential and decreases the proton dissociation energy, making them competitive processes. A positive charge placed at the imino N site, whose value is scanned from zero to one, shows a continuous increase in ionization potential and a decrease in proton dissociation energy, with the +1 limit agreeing well with the protonated imino N site result, indicating a dominant electrostatic effect. The charge populations and the spin density distributions of the His-Tyr model, the radical cation formed by electron ionization, the anion formed by proton dissociation, and the final His-Tyr radical depend sensitively on the substituents, implying a modulation role on the charge transfer between the phenol and imidazole rings, especially for the charged species. His-Tyr and protonated His-Tyr exhibit differences among their respective structural isomers with consequences on their IR absorptions. Small barriers between their pseudo-cis and pseudo-trans rotamers demonstrate the relative flexibility between the two rings, and these may facilitate proton release and charge transfer. The cation effect demonstrates that the cationized cross-linked His-Tyr should be the best candidate to mimic the covalently ring-linked histidine-tyrosine structure in CcO.
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Affiliation(s)
- Yuxiang Bu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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36
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Imbert C, Hratchian HP, Lanznaster M, Heeg MJ, Hryhorczuk LM, McGarvey BR, Schlegel HB, Verani CN. Influence of Ligand Rigidity and Ring Substitution on the Structural and Electronic Behavior of Trivalent Iron and Gallium Complexes with Asymmetric Tridentate Ligands. Inorg Chem 2005; 44:7414-22. [PMID: 16212367 DOI: 10.1021/ic050658j] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Species 1-6 are [M(III)(L)2]ClO4 complexes formed with the PhO--CH=N-CH2-Py imines, (L(I))- and (L(tBuI))-, and PhO--CH2-NH-CH2-Py amines, (L(A))- and (L(tBuA))-, in which PhO- is a phenolate ring and Py is a pyridine ring and the prefix tBu indicates the presence of tertiary butyl groups occupying the positions 4 and 6 of the phenol ring. Monometallic species with d5 high-spin iron (1, 2, 3, 4) and d10 gallium (5, 6) were synthesized and characterized to assess the influence of the ligand rigidity and the presence of tertiary butyl-substituted phenol rings on their steric, electronic, and redox behavior. Characterization by elemental analysis, mass spectrometry, IR, UV-visible, and EPR spectroscopies, and electrochemistry has been performed, and complexes [FeIII(L(tBuI))2]ClO4 (2), [FeIII(L(tBuA))2]ClO4 (4), and [Ga(III)(L(tBuI))2]ClO4 (5) have been characterized by X-ray crystallography. The crystal structures show the imine ligands meridionally coordinated to the metal centers, whereas the amine ligands are coordinate in a facial mode. Cyclic voltammetry shows that the complexes with the ligands (L(tBuI))- and (L(tBuA))- were able to generate ligand-based phenoxyl radicals, whereas unsubstituted ligands displayed ill-defined redox processes. EPR spectroscopy supports high-spin configurations for the iron complexes. UV-visible spectra are dominated by charge-transfer phenomena, and imine compounds exhibit dramatic hyperchromism when compared to equivalent amines. The tertiary butyl groups on the phenolate ring enhance this trend. Detailed B3LYP/6-31G(d)-level calculations have been used to account for the results observed.
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Affiliation(s)
- Camille Imbert
- Department of Chemistry, Wayne State University, 5101 Cass Ave. Detroit, Michigan 48202, USA
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37
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Hegetschweiler K, Egli A, Herdtweck E, Herrmann W, Alberto R, Gramlich V. 1,3,5-Triamino-1,3,5-trideoxy-cis-inositol, a Ligand with a Remarkable Versatility for Metal Ions. Part XIII. Helv Chim Acta 2005. [DOI: 10.1002/hlca.200590027] [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]
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38
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Berthomieu C, Hienerwadel R. Vibrational spectroscopy to study the properties of redox-active tyrosines in photosystem II and other proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1707:51-66. [PMID: 15721606 DOI: 10.1016/j.bbabio.2004.03.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Accepted: 03/31/2004] [Indexed: 11/27/2022]
Abstract
Tyrosine radicals play catalytic roles in essential metalloenzymes. Their properties--midpoint potential, stability...--or environment varies considerably from one enzyme to the other. To understand the origin of these properties, the redox tyrosines are studied by a number of spectroscopic techniques, including Fourier transform infrared (FTIR) and resonance Raman (RR) spectroscopy. An increasing number of vibrational data are reported for the (modified-) redox active tyrosines in ribonucleotide reductases, photosystem II, heme catalase and peroxidases, galactose and glyoxal oxidases, and cytochrome oxidase. The spectral markers for the tyrosinyl radicals have been recorded on models of (substituted) phenoxyl radicals, free or coordinated to metals. We review these vibrational data and present the correlations existing between the vibrational modes of the radicals and their properties and interactions formed with their environment: we present that the nu7a(C-O) mode of the radical, observed both by RR and FTIR spectroscopy at 1480-1515 cm(-1), is a sensitive marker of the hydrogen bonding status of (substituted)-phenoxyl and Tyr*, while the nu8a(C-C) mode may probe coordination of the Tyr* to a metal. For photosystem II, the information obtained by light-induced FTIR difference spectroscopy for the two redox tyrosines TyrD and TyrZ and their hydrogen bonding partners is discussed in comparison with those obtained by other spectroscopic methods.
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Affiliation(s)
- Catherine Berthomieu
- CEA-Cadarache, Laboratoire de Bioénergétique Cellulaire, UMR 6191 CNRS-CEA-Aix-Marseille II, Univ.-Méditerranée CEA 1000, Bât. 156, F-13108 Saint-Paul-lez-Durance, Cedex, France.
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39
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Model complexes of the active site of galactose oxidase. Effects of the metal ion binding sites. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.04.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Improta R, Barone V. Interplay of Electronic, Environmental, and Vibrational Effects in Determining the Hyperfine Coupling Constants of Organic Free Radicals. Chem Rev 2004; 104:1231-54. [PMID: 15008622 DOI: 10.1021/cr960085f] [Citation(s) in RCA: 299] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roberto Improta
- Dipartimento di Chimica, Università Federico II, Complesso Universitario Monte S Angelo, Via Cintia, I-80126 Napoli, Italy
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Webster RD. In situ electrochemical-ATR-FTIR spectroscopic studies on solution phase 2,4,6-tri-substituted phenoxyl radicals. Electrochem commun 2003. [DOI: 10.1016/s1388-2481(02)00517-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Glaser T, Lügger T. A new tetranuclear iron complex with a [Fe4O6]6+ core: synthesis, structure, spectroscopic and magnetic properties. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(02)00989-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Spanget-Larsen J, Gil M, Gorski A, Blake DM, Waluk J, Radziszewski JG. Vibrations of the phenoxyl radical. J Am Chem Soc 2001; 123:11253-61. [PMID: 11697968 DOI: 10.1021/ja0113596] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phenoxyl radical (C(6)H(5)O) was prepared photochemically in low-temperature argon matrices. The infrared absorption spectra were obtained for C(6)H(5)O and for the isotopically labeled species C(6)D(5)O and 1-(13)C(12)C(5)H(5)O. All but one IR-active fundamental vibrations were detected, most of them not previously observed. Combination of results from IR linear dichroism measurements on photooriented samples, determination of absolute IR intensities with the help of internal standards, analysis of isotopic shifts, and quantum chemical predictions (B3LYP/cc-pVTZ) led to a detailed assignment of phenoxyl radical vibrations. Significant frequency shifts are observed with respect to previously reported data based on resonance Raman studies in polar solutions. For some vibrations, these shifts reflect environment-induced structural changes, such as increase of the quinoid character of the phenoxyl radical in polar media. In particular, the frequency of the CO stretching vibration, readily observable in both IR and Raman experiments, is extremely sensitive to the environment and can thus be used to probe its polarity.
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Affiliation(s)
- J Spanget-Larsen
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA
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Schatzschneider U, Weyhermüller T, Rentschler E. Metal Complexes with Nitronyl Nitroxide Substituted Phenolate Ligands Providing New Magnetic Exchange Interaction Pathways − Synthesis, Structures, Magnetic Dilution Studies, and Ab Initio Calculations. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(200109)2001:10<2569::aid-ejic2569>3.0.co;2-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Visser H, Anxolabéhère-Mallart E, Bergmann U, Glatzel P, Robblee JH, Cramer SP, Girerd JJ, Sauer K, Klein MP, Yachandra VK. Mn K-edge XANES and Kbeta XES studies of two Mn-oxo binuclear complexes: investigation of three different oxidation states relevant to the oxygen-evolving complex of photosystem II. J Am Chem Soc 2001; 123:7031-9. [PMID: 11459481 PMCID: PMC3959873 DOI: 10.1021/ja004306h] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two structurally homologous Mn compounds in different oxidation states were studied to investigate the relative influence of oxidation state and ligand environment on Mn K-edge X-ray absorption near-edge structure (XANES) and Mn Kbeta X-ray emission spectroscopy (Kbeta XES). The two manganese compounds are the di-mu-oxo compound [L'2Mn(III)O2Mn(IV)L'2](ClO4)3, where L' is 1,10-phenanthroline (Cooper, S. R.; Calvin, M. J. Am. Chem. Soc. 1977, 99, 6623-6630) and the linear mono-mu-oxo compound [LMn(III)OMn(III)L](ClO4)2, where L- is the monoanionic N,N-bis(2-pyridylmethyl)-N'-salicylidene-1,2-diaminoethane ligand (Horner, O.; Anxolabéhère-Mallart, E.; Charlot, M. F.; Tchertanov, L.; Guilhem, J.; Mattioli, T. A.; Boussac, A.; Girerd, J.-J. Inorg. Chem. 1999, 38, 1222-1232). Preparative bulk electrolysis in acetonitrile was used to obtain higher oxidation states of the compounds: the Mn(IV)Mn(IV) species for the di-mu-oxo compound and the Mn(III)Mn(IV) and Mn(IV)Mn(IV) species for the mono-mu-oxo compound. IR, UV/vis, EPR, and EXAFS spectra were used to determine the purity and integrity of the various sample solutions. The Mn K-edge XANES spectra shift to higher energy upon oxidation when the ligand environment remains similar. However, shifts in energy are also observed when only the ligand environment is altered. This is achieved by comparing the di-mu-oxo and linear mono-mu-oxo Mn-Mn moieties in equivalent oxidation states, which represent major structural changes. The magnitude of an energy shift due to major changes in ligand environment can be as large as that of an oxidation-state change. Therefore, care must be exercised when correlating the Mn K-edge energies to manganese oxidation states without taking into account the nature of the ligand environment and the overall structure of the compound. In contrast to Mn K-edge XANES, Kbeta XES spectra show less dependence on ligand environment. The Kbeta1,3 peak energies are comparable for the di-mu-oxo and mono-mu-oxo compounds in equivalent oxidation states. The energy shifts observed due to oxidation are also similar for the two different compounds. The study of the different behavior of the XANES pre-edge and main-edge features in conjunction with Kbeta XES provides significant information about the oxidation state and character of the ligand environment of manganese atoms.
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Affiliation(s)
- Hendrik Visser
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Chemistry, University of California, Berkeley, California 94720-5230
| | - Elodie Anxolabéhère-Mallart
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Laboratoire de Chimie Inorganique, UMR CNRS 8613, Université de Paris-Sud, 91405 Orsay, France
| | - Uwe Bergmann
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Applied Science, University of California, Davis, California 95616
| | - Pieter Glatzel
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Applied Science, University of California, Davis, California 95616
| | - John H. Robblee
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Chemistry, University of California, Berkeley, California 94720-5230
| | - Stephen P. Cramer
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Applied Science, University of California, Davis, California 95616
| | - Jean-Jacques Girerd
- Laboratoire de Chimie Inorganique, UMR CNRS 8613, Université de Paris-Sud, 91405 Orsay, France
| | - Kenneth Sauer
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Chemistry, University of California, Berkeley, California 94720-5230
| | - Melvin P. Klein
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Vittal K. Yachandra
- Melvin Calvin Laboratory, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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Itoh S, Kumei H, Nagatomo S, Kitagawa T, Fukuzumi S. Effects of metal ions on physicochemical properties and redox reactivity of phenolates and phenoxyl radicals: mechanistic insight into hydrogen atom abstraction by phenoxyl radical-metal complexes. J Am Chem Soc 2001; 123:2165-75. [PMID: 11456861 DOI: 10.1021/ja0036110] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phenolate and phenoxyl radical complexes of a series of alkaline earth metal ions as well as monovalent cations such as Na+ and K+ have been prepared by using 2,4-di-tert-butyl-6-(1,4,7,10-tetraoxa-13-aza-cyclopentadec-13-ylmethyl)phenol (L1H) and 2,4-di-tert-butyl-6-(1,4,7,10,13-pentaoxa-16-aza-cyclooctadec-16-ylmethyl)phenol (L2H) to examine the effects of the cations on the structure, physicochemical properties and redox reactivity of the phenolate and phenoxyl radical complexes. Crystal structures of the Mg2+- and Ca2+-complexes of L1- as well as the Ca2+- and Sr2+-complexes of L2- were determined by X-ray crystallographic analysis, showing that the crown ether rings in the Ca2+-complexes are significantly distorted from planarity, whereas those in the Mg2+- and Sr2+-complexes are fairly flat. The spectral features (UV-vis) as well as the redox potentials of the phenolate complexes are also influenced by the metal ions, depending on the Lewis acidity of the metal ions. The phenoxyl radical complexes are successfully generated in situ by the oxidation of the phenolate complexes with (NH4)(2)[Ce4+(NO3)6] (CAN). They exhibited strong absorption bands around 400 nm together with a broad one around 600-900 nm, the latter of which is also affected by the metal ions. The phenoxyl radical-metal complexes are characterized by resonance Raman, ESI-MS, and ESR spectra, and the metal ion effects on those spectroscopic features are also discussed. Stability and reactivity of the phenoxyl radical-metal complexes are significantly different, depending on the type of metal ions. The disproportionation of the phenoxyl radicals is significantly retarded by the electronic repulsion between the metal cation and a generated organic cation (Ln+), leading to stabilization of the radicals. On the other hand, divalent cations decelerate the rate of hydrogen atom abstraction from 10-methyl-9,10-dihydroacridine (AcrH2) and its 9-substituted derivatives (AcrHR) by the phenoxyl radicals. On the basis of primary kinetic deuterium isotope effects and energetic consideration of the electron-transfer step from AcrH2 to the phenoxyl radical-metal complexes, we propose that the hydrogen atom abstraction by the phenoxyl radical-alkaline earth metal complexes proceeds via electron transfer followed by proton transfer.
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Affiliation(s)
- S Itoh
- Contribution from the Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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Wheeler RA. Quinones and quinoidal radicals in photosynthesis. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1380-7323(01)80016-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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Hudecek J, Anzenbacherová E, Anzenbacher P, Munro AW, Hildebrandt P. Structural similarities and differences of the heme pockets of various P450 isoforms as revealed by resonance Raman spectroscopy. Arch Biochem Biophys 2000; 383:70-8. [PMID: 11097178 DOI: 10.1006/abbi.2000.2034] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytochromes P450 CYP102 A1, 1A2, and 3A4, all belonging to the class II type of P450 enzymes, were studied by resonance Raman spectroscopy. Spectra were measured for the oxidized substrate-free, oxidized substrate-bound, and reduced forms of each of these P450s. The analysis of the resonance Raman spectra indicates that the individual isoforms differ with respect to orientation and conformations of the heme side chains, whereas the overall porphyrin geometry is essentially the same. In the oxidized state, the vinyl groups exhibit both a coplanar and an out-of-plane orientation with respect to the heme, albeit with different relative propensities in the various isoforms. In the reduced state, both vinyl groups are forced into a coplanar orientation. In addition to the differences in behavior of the vinyl groups, the redox-linked spectral changes also include the bending mode of the propionate side chains. The spectral differences associated with the porphyrin substituents are likely to reflect subtle conformational differences in the heme pocket of various P450 isoforms which may constitute the structural basis for the known variability of their functions.
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Affiliation(s)
- J Hudecek
- Department of Biochemistry, Charles University, Prague, Czech Republic.
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50
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Zhan CG, Wang QL, Xiong Y, Chen X. Maximum bond order hybrid orbital calculations of C O bond stretching vibrational frequencies. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0166-1280(00)00396-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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