1
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Bruckhoff T, Ballmann J, Gade LH. Radicalizing CO by Mononuclear Palladium(I). Angew Chem Int Ed Engl 2024; 63:e202320064. [PMID: 38498121 DOI: 10.1002/anie.202320064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/06/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024]
Abstract
A mononuclear, T-shaped palladium(I) d9 metalloradical (3), stabilized by a bulky carbazole-based PNP-ligand, was obtained by reduction of palladium chloride or thermal Pd-C bond homolysis of the corresponding neopentyl complex. Pressurizing with CO gave the Pd(I) carbonyl complex, which was structurally characterized by X-ray diffraction. Delocalization of the unpaired electron to the carbonyl carbon was detected by EPR spectroscopy and theoretically modeled by DFT and ab initio methods. The partially reduced and radicalized CO slowly reacts with di(tert-butyl) disulfide under homolytic S-S cleavage and C-S bond formation to give the corresponding metallathioester.
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Affiliation(s)
- Tim Bruckhoff
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Joachim Ballmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
| | - Lutz H Gade
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120, Heidelberg, Germany
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2
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Yu Z, Blade G, Bouley BS, Dobrucki IT, Dobrucki LW, Mirica LM. Coordination Chemistry of Sulfur-Containing Bifunctional Chelators: Toward in Vivo Stabilization of 64Cu PET Imaging Agents for Alzheimer's Disease. Inorg Chem 2023; 62:20820-20833. [PMID: 38060375 DOI: 10.1021/acs.inorgchem.3c02929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The broader utilization of 64Cu positron emission tomography (PET) imaging agents has been hindered by the unproductive demetalation induced by bioreductants. To advance the development of 64Cu-based PET imaging tracers for Alzheimer's Disease (AD), there is a need for novel ligand design strategies. In this study, we developed sulfur-containing dithiapyridinophane (N2S2) bifunctional chelators (BFCs) as well as all nitrogen-based diazapyridinophane (N4) BFCs to compare their abilities to chelate Cu and target Aβ aggregates. Through spectrophotometric titrations and electrochemical measurements, we have demonstrated that the N2S2-based BFCs exhibit >10 orders of magnitude higher binding affinity toward Cu(I) compared to their N4-based counterparts, while both types of BFCs exhibit high stability constants toward Cu(II). Notably, solid state structures for both Cu(II) and Cu(I) complexes supported by the two ligand frameworks were obtained, providing molecular insights into their copper chelating abilities. Aβ binding experiments were conducted to study the structure-affinity relationship, and fluorescence microscopy imaging studies confirmed the selective labeling of the BFCs and their copper complexes. Furthermore, we investigated the potential of these ligands for the 64Cu-based PET imaging of AD through radiolabeling and autoradiography studies. We believe our findings provide molecular insights into the design of bifunctional Cu chelators that can effectively stabilize both Cu(II) and Cu(I) and, thus, can have significant implications for the development of 64Cu PET imaging as a diagnostic tool for AD.
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Affiliation(s)
- Zhengxin Yu
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Glenn Blade
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Bailey S Bouley
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Iwona T Dobrucki
- Beckman Institute for Advanced Science and Technology, Department of Bioengineering, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Lawrence W Dobrucki
- Beckman Institute for Advanced Science and Technology, Department of Bioengineering, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
| | - Liviu M Mirica
- Department of Chemistry, Beckman Institute for Advanced Science and Technology, The Neuroscience Program, Carle Illinois College of Medicine, University of Illinois at Urbana─Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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3
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Maties G, Gómez-Sal P, Yebra CG, Andrés R, de Jesús E. Reversible Single-Electron-Transfer to Oxygen in a Stable N-Heterocyclic Carbene Palladium(I) Metalloradical. Inorg Chem 2023. [PMID: 37992293 DOI: 10.1021/acs.inorgchem.3c02878] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
The chemical and electrochemical one-electron oxidation of [Pd(IPr)2] (1) leads to the formation of mononuclear palladium(I) complex [Pd(IPr)2][PF6] (2). This bench-stable metalloradical has been fully characterized and its structure confirmed by X-ray diffraction analysis. EPR and DFT studies confirm the localization of the unpaired electron onto the metal center. Low temperature NMR and EPR measurements reveal the ability of complex 2 to reversibly coordinate and reduce the dioxygen molecule, leading to the formation of a three-coordinate complex, [PdII(IPr)2(η1-O2)]+ (4), in which the unpaired electron has been transferred to the superoxido ligand.
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Affiliation(s)
- Georgiana Maties
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río", Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Pilar Gómez-Sal
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río", Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Cristina G Yebra
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río", Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Román Andrés
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río", Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
| | - Ernesto de Jesús
- Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Química "Andrés M. del Río", Universidad de Alcalá, Campus Universitario, 28805 Alcalá de Henares, Madrid, Spain
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4
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Zhang X, Xu Y, Shen Y, Wang F. Simple Coumarin-Based Fluorescent Probe for Recognition of Pd(II) and Its Live Cell Imaging. ACS OMEGA 2023; 8:35121-35126. [PMID: 37779989 PMCID: PMC10536022 DOI: 10.1021/acsomega.3c04626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/31/2023] [Indexed: 10/03/2023]
Abstract
A simple coumarin hydrazine Schiff base bearing a thioether recognition fragment (compound CBBS) has been rationally designed and easily prepared. CBBS exhibited an excellent selectivity for Pd(II) and a low detection limit of 65 nM (S/N = 3). The fluorescence emission intensities of CBBS at 495 nm were linear to Pd(II) concentrations in a wide range from 0 to 80 μM. Moreover, CBBS has been well used in fluorescence imaging of Pd(II) in living A549 cells. CBBS as a simple coordination-based fluorescent probe will inspire the researchers to develop a polymer for selective detection and adsorption of Pd(II).
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Affiliation(s)
- Xiangyang Zhang
- College
of Chemistry and Material Engineering, Hunan
University of Arts and Science, Changde 415000, P. R. China
- Changde
Engineering Technology Research Center of Biomedical Polymer Materials, Changde 415000, P. R. China
| | - Yaodan Xu
- College
of Chemistry and Material Engineering, Hunan
University of Arts and Science, Changde 415000, P. R. China
- Changde
Engineering Technology Research Center of Biomedical Polymer Materials, Changde 415000, P. R. China
| | - Youming Shen
- College
of Chemistry and Material Engineering, Hunan
University of Arts and Science, Changde 415000, P. R. China
- Changde
Engineering Technology Research Center of Biomedical Polymer Materials, Changde 415000, P. R. China
| | - Feifei Wang
- College
of Chemistry and Material Engineering, Hunan
University of Arts and Science, Changde 415000, P. R. China
- Changde
Engineering Technology Research Center of Biomedical Polymer Materials, Changde 415000, P. R. China
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5
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Zhang P, Newhouse TR. Palladium-Catalyzed Carbonylative Difunctionalization of Unactivated Alkenes Initiated by Unstabilized Enolates. Angew Chem Int Ed Engl 2023; 62:e202307455. [PMID: 37319375 PMCID: PMC11090370 DOI: 10.1002/anie.202307455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/17/2023]
Abstract
This report describes the first example of palladium-catalyzed carbonylative difunctionalization of unactivated alkenes initiated by enolate nucleophiles. The approach involves initiation by an unstabilized enolate nucleophile under an atmospheric pressure of CO and termination with a carbon electrophile. This process is compatible with a diverse range of electrophiles, including aryl, heteroaryl, and vinyl iodides to yield synthetically useful 1,5-diketone products, which were demonstrated to be precursors for multi-substituted pyridines. A PdI -dimer complex with two bridging CO units was observed although its role in catalysis is not yet understood.
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Affiliation(s)
- Pengpeng Zhang
- Department of Chemistry, Yale University, 225 Prospect Street, PO Box 208107, New Haven, CT, 06511
| | - Timothy R. Newhouse
- Department of Chemistry, Yale University, 225 Prospect Street, PO Box 208107, New Haven, CT, 06511
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