1
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Aschendorf CJ, Degbevi M, Prather KV, Tsui EY. EPR spin trapping of nucleophilic and radical reactions at colloidal metal chalcogenide quantum dot surfaces. Chem Sci 2023; 14:13080-13089. [PMID: 38023529 PMCID: PMC10664490 DOI: 10.1039/d3sc04724e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023] Open
Abstract
The participation of the surfaces of colloidal semiconductor nanocrystal quantum dots (QDs) in QD-mediated photocatalytic reactions is an important factor that distinguishes QDs from other photosensitizers (e.g. transition metal complexes or organic dyes). Here, we probe nucleophilic and radical reactivity of surface sulfides and selenides of metal chalcogenide (CdSe, CdS, ZnSe, and PbS) QDs using chemical reactions and NMR spectroscopy. Additionally, the high sensitivity of EPR spectroscopy is adapted to study these surface-centered reactions through the use of spin traps like 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) under photoexcitation and thermal conditions. We demonstrate that DMPO likely adds to CdSe QD surfaces under thermal conditions by a nucleophilic mechanism in which the surface chalcogenides add to the double bond, followed by further oxidation of the surface-bound product. In contrast, CdS QDs more readily form surface sulfur-centered radicals that can perform reactions including alkene isomerization. These results indicate that QD surfaces should be an important consideration for the design of photocatalysis beyond simply tuning QD semiconductor band gaps.
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Affiliation(s)
- Caroline J Aschendorf
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame IN USA
| | - Mawuli Degbevi
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame IN USA
| | - Keaton V Prather
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame IN USA
| | - Emily Y Tsui
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame IN USA
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2
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Keul F, Mardyukov A. Generation and reactivity of vinyltelluryl radical. Phys Chem Chem Phys 2022; 24:15129-15134. [PMID: 35699397 DOI: 10.1039/d2cp01658c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vinyltelluryl radical was prepared by high-vacuum flash pyrolysis from the corresponding divinylditelluride and trapped in an argon matrix at 10 K. The title compound was characterized by IR and UV/Vis spectroscopy, and all experimental data match well with density functional theory at the UB3LYP/def2-QZVPP level. According to UB3LYP/def2-QZVPP computations, the spin density is mainly localized on the Te atom. The vinylogy principle for the vinyltelluryl radical is not applicable due to the lack of delocalization of spin density. Upon irradiation of the matrix with light (λ = 365 nm), the vinyltelluryl radical rearranges to a H-Te˙⋯acetylene complex. Doping the matrix with molecular oxygen leads to the hitherto unknown vinyltelluro peroxy radical. The latter isomerizes to the more thermodynamically stable vinyltelluroyl radical by irradiation with light at λ = 523 nm.
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Affiliation(s)
- Felix Keul
- Institute of Organic Chemistry Justus-Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
| | - Artur Mardyukov
- Institute of Organic Chemistry Justus-Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
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3
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James AK, Dolgova NV, Nehzati S, Korbas M, Cotelesage JJH, Sokaras D, Kroll T, O’Donoghue JL, Watson GE, Myers GJ, Pickering IJ, George GN. Molecular Fates of Organometallic Mercury in Human Brain. ACS Chem Neurosci 2022; 13:1756-1768. [PMID: 35543423 PMCID: PMC9977140 DOI: 10.1021/acschemneuro.2c00166] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mercury is ubiquitous in the environment, with rising levels due to pollution and climate change being a current global concern. Many mercury compounds are notorious for their toxicity, with the potential of organometallic mercury compounds for devastating effects on the structures and functions of the central nervous system being of particular concern. Chronic exposure of human populations to low levels of methylmercury compounds occurs through consumption of fish and other seafood, although the health consequences, if any, from this exposure remain controversial. We have used high energy resolution fluorescence detected X-ray absorption spectroscopy to determine the speciation of mercury and selenium in human brain tissue. We show that the molecular fate of mercury differs dramatically between individuals who suffered acute organometallic mercury exposure (poisoning) and individuals with chronic low-level exposure from a diet rich in marine fish. For long-term low-level methylmercury exposure from fish consumption, mercury speciation in brain tissue shows methylmercury coordinated to an aliphatic thiolate, resembling the coordination environment observed in marine fish. In marked contrast, for short-term high-level exposure, we observe the presence of biologically less available mercuric selenide deposits, confirmed by X-ray fluorescence imaging, as well as mercury(II)-bis-thiolate complexes, which may be signatures of severe poisoning in humans. These differences between low-level and high-level exposures challenge the relevance of studies involving acute exposure as a proxy for low-level chronic exposure.
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Affiliation(s)
- Ashley K. James
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V. Dolgova
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Susan Nehzati
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Malgorzata Korbas
- Canadian Light Source, 44 Innovation Blvd, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Julien J. H. Cotelesage
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - John L. O’Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gene E. Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Gary J. Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
| | - Ingrid J. Pickering
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.,Corresponding Authors: Ingrid J. Pickering – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada; , Graham N. George – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada;
| | - Graham N. George
- Toxicology Centre, 44 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.,Corresponding Authors: Ingrid J. Pickering – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada; , Graham N. George – Department of Geological Sciences, Toxicology Centre, and Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5E2, Canada;
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4
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Cutsail III GE, DeBeer S. Challenges and Opportunities for Applications of Advanced X-ray Spectroscopy in Catalysis Research. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- George E. Cutsail III
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
- Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, 45117 Essen, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
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5
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Henthorn JT, DeBeer S. Selenium Valence-to-Core X-ray Emission Spectroscopy and Kβ HERFD X-ray Absorption Spectroscopy as Complementary Probes of Chemical and Electronic Structure. Inorg Chem 2022; 61:2760-2767. [PMID: 35113562 PMCID: PMC8848279 DOI: 10.1021/acs.inorgchem.1c02802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Selenium X-ray absorption
spectroscopy (XAS) has found widespread
use in investigations of Se-containing materials, geochemical processes,
and biologically active sites. In contrast to sulfur Kβ X-ray
emission spectroscopy (XES), which has been found to contain electronic
and structural information complementary to S XAS, Se Kβ XES
remains comparatively underexplored. Herein, we present the first
Se Valence-to-Core (VtC) XES studies of reduced Se-containing compounds
and FeSe dimers. Se VtC XES is found to be sensitive to changes in
covalent Se bonding interactions (Se–Se/Se–C/Se–H
bonding) while being relatively insensitive to changes in Fe oxidation
states as selenide bridges in FeSe dimers ([Fe2Se2]2+ vs [Fe2Se2]+). In
contrast, Se Kβ HERFD XAS is demonstrated to be quite sensitive
to changes in the Fe oxidation state with Se Kβ HERFD XAS demonstrating
experimental resolution equivalent to Kα HERFD XAS. Additionally,
computational studies reveal both Se VtC XES and XAS to be sensitive
to selenium protonation in FeSe complexes. Selenium is a trace element that plays
vital roles in biological
and geochemical cycles, energy storage, photovoltaics, and nanomaterials.
Herein, selenium Valence-to-Core X-ray emission spectroscopy is explored
as a new method of probing the chemical and electronic structure in
selenium-containing compounds, demonstrating sensitivity to selenium
bonding interactions. When paired with high-resolution Se X-ray absorption
spectroscopy (HERFD XAS), these two methods have the potential to
reveal greater insight into protonation and redox changes of Se-substituted
FeS clusters.
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Affiliation(s)
- Justin T Henthorn
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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6
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Wen X, Wang S, Liu R, Duan R, Hu S, Jiao T, Zhang L, Liu M. Selenocystine and Photo-Irradiation Directed Growth of Helically Grooved Gold Nanoarrows. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2104301. [PMID: 34825484 DOI: 10.1002/smll.202104301] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/28/2021] [Indexed: 06/13/2023]
Abstract
The fabrication of discrete nanostructures with both plasmonic circular dichroism (PCD) and chiral features is still a challenge. Here, gold nanoarrows (GNAs) with both chiroptical responses and chiral morphologies are achieved by using L-selenocystine (L-SeCys2 ) as a chiral inducer. While L-SeCys2 generates GNAs with a weak PCD signal, the irradiated L-SeCys2 (irr-L-SeCys2 ) leads to GNAs with featured helical grooves (HeliGNAs) accompanying with a strong PCD signal. It is revealed that when L-SeCys2 is photo-irradiated, the emergence of selenyl radicals plays an important role in the formation of HeliGNAs and enhancement of the chiroptical signal. In comparison with L-SeCys2 and the other kinds of sulfur-containing amino acids, the formation mechanism of helical grooves on the surface of GNAs is proposed. Both HeliGNAs and GNAs are used to discriminate amino acids by utilizing surface enhanced Raman scattering (SERS) effect. In the presence of either GNAs or HeliGNAs as the substrate, Fmoc-L-Phe shows more significant SERS than Fmoc-D-Phe. This study may advance the design of discrete plasmonic nanomaterials with both chiral morphology and potential applications in discrimination of chiral molecules.
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Affiliation(s)
- Xin Wen
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, 066004, P. R. China
- CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Song Wang
- CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Rulin Liu
- Shenzhen Institute of Artificial Intelligence and Robotics for Society (AIRS), Shenzhen, 518172, P. R. China
| | - Ran Duan
- Key Laboratory of Photochemistry Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Song Hu
- CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Tifeng Jiao
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, 066004, P. R. China
| | - Li Zhang
- CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Minghua Liu
- CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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7
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Nehzati S, Dolgova NV, James AK, Cotelesage JJH, Sokaras D, Kroll T, George GN, Pickering IJ. High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy: An Analytical Method for Selenium Speciation. Anal Chem 2021; 93:9235-9243. [PMID: 34164981 DOI: 10.1021/acs.analchem.1c01503] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Selenium is in many ways an enigmatic element. It is essential for health but toxic in excess, with the difference between the two doses being narrower than for any other element. Environmentally, selenium is of concern due to its toxicity. As the rarest of the essential elements, its low levels often provide challenges to the analytical chemist. X-ray absorption spectroscopy (XAS) provides a powerful tool for in situ chemical speciation but is severely limited by poor spectroscopic resolution arising from core-hole lifetime broadening. Here we explore selenium Kα1 high energy resolution fluorescence detected XAS (HERFD-XAS) as a novel approach for chemical speciation of selenium, in comparison with conventional Se K-edge XAS. We present spectra of a range of selenium species relevant to environmental and life science studies, including spectra of seleno-amino acids, which show strong similarities with S K-edge XAS of their sulfur congeners. We discuss strengths and limitations of HERFD-XAS, showing improvements in both speciation performance and low concentration detection. We also develop a simple method to correct fluorescence self-absorption artifacts, which is generally applicable to any HERFD-XAS experiment.
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Affiliation(s)
- Susan Nehzati
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Ashley K James
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Julien J H Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.,Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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8
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Abdillah A, Sonawane PM, Kim D, Mametov D, Shimodaira S, Park Y, Churchill DG. Discussions of Fluorescence in Selenium Chemistry: Recently Reported Probes, Particles, and a Clearer Biological Knowledge. Molecules 2021; 26:692. [PMID: 33525729 PMCID: PMC7866183 DOI: 10.3390/molecules26030692] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/15/2022] Open
Abstract
In this review from literature appearing over about the past 5 years, we focus on selected selenide reports and related chemistry; we aimed for a digestible, relevant, review intended to be usefully interconnected within the realm of fluorescence and selenium chemistry. Tellurium is mentioned where relevant. Topics include selenium in physics and surfaces, nanoscience, sensing and fluorescence, quantum dots and nanoparticles, Au and oxide nanoparticles quantum dot based, coatings and catalyst poisons, thin film, and aspects of solar energy conversion. Chemosensing is covered, whether small molecule or nanoparticle based, relating to metal ion analytes, H2S, as well as analyte sulfane (biothiols-including glutathione). We cover recent reports of probing and fluorescence when they deal with redox biology aspects. Selenium in therapeutics, medicinal chemistry and skeleton cores is covered. Selenium serves as a constituent for some small molecule sensors and probes. Typically, the selenium is part of the reactive, or active site of the probe; in other cases, it is featured as the analyte, either as a reduced or oxidized form of selenium. Free radicals and ROS are also mentioned; aggregation strategies are treated in some places. Also, the relationship between reduced selenium and oxidized selenium is developed.
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Affiliation(s)
- Ariq Abdillah
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - Prasad M. Sonawane
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - Donghyeon Kim
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - Dooronbek Mametov
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - Shingo Shimodaira
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - Yunseon Park
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
| | - David G. Churchill
- Molecular Logic Gate Laboratory, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; (A.A.); (P.M.S.); (D.K.); (D.M.); (S.S.); (Y.P.)
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
- KAIST Institute for Health Science and Technology (KIHST) (Therapeutic Bioengineering), Daejeon 34141, Korea
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9
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Summers KL, Roseman GP, Sopasis GJ, Millhauser GL, Harris HH, Pickering IJ, George GN. Copper(II) Binding to PBT2 Differs from That of Other 8-Hydroxyquinoline Chelators: Implications for the Treatment of Neurodegenerative Protein Misfolding Diseases. Inorg Chem 2020; 59:17519-17534. [PMID: 33226796 PMCID: PMC7927943 DOI: 10.1021/acs.inorgchem.0c02754] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PBT2 (5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline) is a small Cu(II)-binding drug that has been investigated in the treatment of neurodegenerative diseases, namely, Alzheimer's disease (AD). PBT2 is thought to be highly effective at crossing the blood-brain barrier and has been proposed to exert anti-Alzheimer's effects through the modulation of metal ion concentrations in the brain, specifically the sequestration of Cu(II) from amyloid plaques. However, despite promising initial results in animal models and in clinical trials where PBT2 was shown to improve cognitive function, larger-scale clinical trials did not find PBT2 to have a significant effect on the amyloid plaque burden compared with controls. We propose that the results of these clinical trials likely point to a more complex mechanism of action for PBT2 other than simple Cu(II) sequestration. To this end, herein we have investigated the solution chemistry of Cu(II) coordination by PBT2 primarily using X-ray absorption spectroscopy (XAS), high-energy-resolution fluorescence-detected XAS, and electron paramagnetic resonance. We propose that a novel bis-PBT2 Cu(II) complex with asymmetric coordination may coexist in solution with a symmetric four-coordinate Cu(II)-bis-PBT2 complex distorted from coplanarity. Additionally, PBT2 is a more flexible ligand than other 8HQs because it can act as both a bidentate and a tridentate ligand as well as coordinate Cu(II) in both 1:1 and 2:1 PBT2/Cu(II) complexes.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham P Roseman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - George J Sopasis
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - Hugh H Harris
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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10
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James AK, Nehzati S, Dolgova NV, Sokaras D, Kroll T, Eto K, O'Donoghue JL, Watson GE, Myers GJ, Krone PH, Pickering IJ, George GN. Rethinking the Minamata Tragedy: What Mercury Species Was Really Responsible? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2726-2733. [PMID: 31951385 DOI: 10.1021/acs.est.9b06253] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Industrial release of mercury into the local Minamata environment with consequent poisoning of local communities through contaminated fish and shellfish consumption is considered the classic case of environmental mercury poisoning. However, the mercury species in the factory effluent has proved controversial, originally suggested as inorganic, and more recently as methylmercury species. We used newly available methods to re-examine the cerebellum of historic Cat 717, which was fed factory effluent mixed with food to confirm the source. Synchrotron high-energy-resolution fluorescence detection-X-ray absorption spectroscopy revealed sulfur-bound organometallic mercury with a minor β-HgS phase. Density functional theory indicated energetic preference for α-mercuri-acetaldehyde as a waste product of aldehyde production. The consequences of this alternative species in the "classic" mercury poisoning should be re-evaluated.
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Affiliation(s)
- Ashley K James
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Susan Nehzati
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V Dolgova
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Komyo Eto
- National Institute for Minamata Disease, Ministry of the Environment,, Kumamoto 867-0008, Japan
| | - John L O'Donoghue
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Gene E Watson
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
- Eastman Institute for Oral Health, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Gary J Myers
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
- Departments of Neurology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, United States
| | - Patrick H Krone
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
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Hu H, Zhao J, Wang L, Shang L, Cui L, Gao Y, Li B, Li YF. Synchrotron-based techniques for studying the environmental health effects of heavy metals: Current status and future perspectives. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.115721] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Summers KL, Schilling KM, Roseman G, Markham KA, Dolgova NV, Kroll T, Sokaras D, Millhauser GL, Pickering IJ, George GN. X-ray Absorption Spectroscopy Investigations of Copper(II) Coordination in the Human Amyloid β Peptide. Inorg Chem 2019; 58:6294-6311. [PMID: 31013069 DOI: 10.1021/acs.inorgchem.9b00507] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Alzheimer's disease (AD) is the main cause of age-related dementia and currently affects approximately 5.7 million Americans. Major brain changes associated with AD pathology include accumulation of amyloid beta (Aβ) protein fragments and formation of extracellular amyloid plaques. Redox-active metals mediate oligomerization of Aβ, and the resultant metal-bound oligomers have been implicated in the putative formation of harmful, reactive species that could contribute to observed oxidative damage. In isolated plaque cores, Cu(II) is bound to Aβ via histidine residues. Despite numerous structural studies of Cu(II) binding to synthetic Aβ in vitro, there is still uncertainty surrounding Cu(II) coordination in Aβ. In this study, we used X-ray absorption spectroscopy (XAS) and high energy resolution fluorescence detected (HERFD) XAS to investigate Cu(II) coordination in Aβ(1-42) under various solution conditions. We found that the average coordination environment in Cu(II)Aβ(1-42) is sensitive to X-ray photoreduction, changes in buffer composition, peptide concentration, and solution pH. Fitting of the extended X-ray absorption fine structure (EXAFS) suggests Cu(II) is bound in a mixture of coordination environments in monomeric Aβ(1-42) under all conditions studied. However, it was evident that on average only a single histidine residue coordinates Cu(II) in monomeric Aβ(1-42) at pH 6.1, in addition to 3 other oxygen or nitrogen ligands. Cu(II) coordination in Aβ(1-42) at pH 7.4 is similarly 4-coordinate with oxygen and nitrogen ligands, although an average of 2 histidine residues appear to coordinate at this pH. At pH 9.0, the average Cu(II) coordination environment in Aβ(1-42) appears to be 5-coordinate with oxygen and nitrogen ligands, including two histidine residues.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | - Kevin M Schilling
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Graham Roseman
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Kate A Markham
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
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George GN, Pickering IJ, Cotelesage JJH, Vogt LI, Dolgova NV, Regnier N, Sokaras D, Kroll T, Sneeden EY, Hackett MJ, Goto K, Block E. Visualizing sulfur with X-rays: From molecules to tissues. PHOSPHORUS SULFUR 2019. [DOI: 10.1080/10426507.2019.1602618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Graham N. George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | - Ingrid J. Pickering
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | | | - Linda I. Vogt
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Natalia V. Dolgova
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Nathan Regnier
- Department of Chemistry, University of Saskatchewan, Saskatoon, Canada
| | | | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California, USA
| | - Eileen Y. Sneeden
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California, USA
| | - Mark J. Hackett
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Kei Goto
- Department of Chemistry, Tokyo Institute of Technology, Tokyo, Japan
| | - Eric Block
- Department of Chemistry, University at Albany – State University of New York, Albany, New York, USA
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