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Keot N, Sarma M. Probing the dynamic behaviour and magnetic identification of seven coordinated Mn(II) complexes: a combined AIMD and multi-reference approach. Phys Chem Chem Phys 2023; 25:31165-31177. [PMID: 37953737 DOI: 10.1039/d3cp04072k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
We present an in-depth solution phase dynamics of rare seven coordinated pentagonal bipyramidal Mn(II) complexes, together with their binding affinity anticipated using ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT). Moreover, the simulations at different temperatures (25 °C and 90 °C) interpret the rigidity and stability of the ligands with Mn(II) ions. An intuitive approach for modulating the easy plane magnetic anisotropy of the mononuclear Mn(II) complex has been revealed by this work. In this regard, we have performed an extensive theoretical study based on the ab initio CASSCF/NEVPT2 method, exhibiting the presence of an easy plane magnetic anisotropy with a positive value of axial zero-field splitting (ZFS) parameter D. The complex's magnetic properties and electronic relaxation reveal that the rhombic ZFS term (E) can be modulated as the symmetry around the Mn(II) ion varies. The magnitude of the D-value increased with a more symmetrical equatorial ligand as found in the order of [Mn(pydpa)(H2O)] > [Mn(cbda)(H2O)]- > [Mn(dpaaa)(H2O)]- > [Mn(dpasam)(H2O)]-. Furthermore, we found that substituting the equatorial oxygen atom with heavier S and Se-donor atoms switches the sign of magnetic anisotropy for the Mn(II) complexes. The magnitude of the D-value increased when the energy levels of the ground state (GS) and the first excited state (ES) decreased. The observed magneto-structural correlation reveals that shortening the distance of the axial water molecule (Mn-O(w)) increases the D-value by an order of magnitude for the symmetrical [Mn(pydpa)(H2O)] complex. Overall, the combined analysis of solution phase dynamics of Mn(II) complexes and their magnetic characterization opens up new avenues in coordination chemistry, molecular magnetism, spin-crossover materials, and catalysis.
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Affiliation(s)
- Niharika Keot
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India.
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2
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Henoumont C, Devreux M, Laurent S. Mn-Based MRI Contrast Agents: An Overview. Molecules 2023; 28:7275. [PMID: 37959694 PMCID: PMC10648041 DOI: 10.3390/molecules28217275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
MRI contrast agents are required in the clinic to detect some pathologies, such as cancers. Nevertheless, at the moment, only small extracellular and non-specific gadolinium complexes are available for clinicians. Moreover, safety issues have recently emerged concerning the use of gadolinium complexes; hence, alternatives are urgently needed. Manganese-based MRI contrast agents could be one of these alternatives and increasing numbers of studies are available in the literature. This review aims at synthesizing all the research, from small Mn complexes to nanoparticular agents, including theranostic agents, to highlight all the efforts already made by the scientific community to obtain highly efficient agents but also evidence of the weaknesses of the developed systems.
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Affiliation(s)
- Céline Henoumont
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
| | - Marie Devreux
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
| | - Sophie Laurent
- NMR and Molecular Imaging Laboratory, Department of General, Organic and Biomedical Chemistry, University of Mons, 19 Avenue Maistriau, 7000 Mons, Belgium; (C.H.)
- Center for Microscopy and Molecular Imaging (CMMI), 8 Rue Adrienne Boland, 6041 Gosselies, Belgium
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3
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Islam MK, Baek AR, Yang BW, Kim S, Hwang DW, Nam SW, Lee GH, Chang Y. Manganese (II) Complex of 1,4,7-Triazacyclononane-1,4,7-Triacetic Acid (NOTA) as a Hepatobiliary MRI Contrast Agent. Pharmaceuticals (Basel) 2023; 16:ph16040602. [PMID: 37111359 PMCID: PMC10141232 DOI: 10.3390/ph16040602] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Magnetic resonance imaging (MRI) is increasingly used to diagnose focal and diffuse liver disorders. Despite their enhanced efficacy, liver-targeted gadolinium-based contrast agents (GBCAs) raise safety concerns owing to the release of toxic Gd3+ ions. A π-conjugated macrocyclic chelate, Mn-NOTA-NP, was designed and synthesized as a non-gadolinium alternative for liver-specific MRI. Mn-NOTA-NP exhibits an r1 relaxivity of 3.57 mM-1 s-1 in water and 9.01 mM-1 s-1 in saline containing human serum albumin at 3 T, which is significantly greater than the clinically utilized Mn2+-based hepatobiliary drug, Mn-DPDP (1.50 mM-1 s-1), and comparable with that of GBCAs. Furthermore, the in vivo biodistribution and MRI enhancement patterns of Mn-NOTA-NP were similar to those of the Gd3+-based hepatobiliary agent, Gd-DTPA-EOB. Additionally, a 0.05 mmol/kg dose of Mn-NOTA-NP facilitated high-sensitivity tumor detection with tumor signal enhancement in a liver tumor model. Ligand-docking simulations further indicated that Mn-NOTA-NP differed from other hepatobiliary agents in their interactions with several transporter systems. Collectively, we demonstrated that Mn-NOTA-NP could be a new liver-specific MRI contrast agent.
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Affiliation(s)
- Md Kamrul Islam
- Institute of Biomedical Engineering Research, Kyungpook National University, Daegu 41405, Republic of Korea
| | - Ah-Rum Baek
- Institute of Biomedical Engineering Research, Kyungpook National University, Daegu 41405, Republic of Korea
| | - Byeong-Woo Yang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Soyeon Kim
- Division of RI-Convergence Research, Korea Institute of Radiological and Medical Sciences, Seoul 01812, Republic of Korea
| | - Dong Wook Hwang
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Sung-Wook Nam
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Gang-Ho Lee
- Department of Chemistry, Kyungpook National University, 80, Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Yongmin Chang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
- Department of Radiology, Kyungpook National University Hospital, Daegu 41944, Republic of Korea
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4
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Uzal-Varela R, Pérez-Fernández F, Valencia L, Rodríguez-Rodríguez A, Platas-Iglesias C, Caravan P, Esteban-Gómez D. Thermodynamic Stability of Mn(II) Complexes with Aminocarboxylate Ligands Analyzed Using Structural Descriptors. Inorg Chem 2022; 61:14173-14186. [PMID: 35994514 PMCID: PMC9455602 DOI: 10.1021/acs.inorgchem.2c02364] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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We present a quantitative analysis of the thermodynamic
stabilities
of Mn(II) complexes, defined by the equilibrium constants (log KMnL values) and the values of pMn obtained as
−log[Mn]free for total metal and ligand concentrations
of 1 and 10 μM, respectively. We used structural descriptors
to analyze the contributions to complex stability of different structural
motifs in a quantitative way. The experimental log KMnL and pMn values can be predicted to a good accuracy
by adding the contributions of the different motifs present in the
ligand structure. This allowed for the identification of features
that provide larger contributions to complex stability, which will
be very helpful for the design of efficient chelators for Mn(II) complexation.
This issue is particularly important to develop Mn(II) complexes for
medical applications, for instance, as magnetic resonance imaging
(MRI) contrast agents. The analysis performed here also indicates
that coordination number eight is more common for Mn(II) than is generally
assumed, with the highest log KMnL values generally observed for hepta- and octadentate ligands. The
X-ray crystal structure of [Mn2(DOTA)(H2O)2], in which eight-coordinate [Mn(DOTA)]2– units are bridged by six-coordinate exocyclic Mn(II) ions, is also
reported. We present empirical relationships
that allow estimating
the log K and pMn values of Mn(II) complexes
relevant as contrast agents for magnetic resonance imaging (MRI).
The prediction of complex stability with these expressions relies
on structural descriptors, providing a very powerful tool to aid with
ligand design.
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Affiliation(s)
- Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Francisco Pérez-Fernández
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Laura Valencia
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain
| | - Aurora Rodríguez-Rodríguez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
| | - Peter Caravan
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 149, 13th Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Galicia, Spain
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5
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Rao Y, Palumbo CT, Venkatesh A, Keener M, Stevanato G, Chauvin AS, Menzildjian G, Kuzin S, Yulikov M, Jeschke G, Lesage A, Mazzanti M, Emsley L. Design Principles for the Development of Gd(III) Polarizing Agents for Magic Angle Spinning Dynamic Nuclear Polarization. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:11310-11317. [PMID: 35865791 PMCID: PMC9289950 DOI: 10.1021/acs.jpcc.2c01721] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Nuclear magnetic resonance suffers from an intrinsically low sensitivity, which can be overcome by dynamic nuclear polarization (DNP). Gd(III) complexes are attractive exogenous polarizing agents for magic angle spinning (MAS) DNP due to their high chemical stability in contrast to nitroxide-based radicals. However, even the state-of-the-art Gd(III) complexes have so far provided relatively low DNP signal enhancements of ca. 36 in comparison to standard DNP biradicals, which show enhancements of over 200. Here, we report a series of new Gd(III) complexes for DNP and show that the observed DNP enhancements of the new and existing Gd(III) complexes are inversely proportional to the square of the zero-field splitting (ZFS) parameter D, which is in turn determined by the ligand-type and the local coordination environment. The experimental DNP enhancements at 9.4 T and the ZFS parameters measured with pulsed electron paramagnetic resonance (EPR) spectroscopy agree with the above model, paving the way for the development of more efficient Gd(III) polarizing agents.
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Affiliation(s)
- Yu Rao
- Laboratory
of Magnetic Resonance, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Chad T. Palumbo
- Group
of Coordination Chemistry, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL, CH-1015 Lausanne, Switzerland
| | - Amrit Venkatesh
- Laboratory
of Magnetic Resonance, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Megan Keener
- Group
of Coordination Chemistry, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL, CH-1015 Lausanne, Switzerland
| | - Gabriele Stevanato
- Laboratory
of Magnetic Resonance, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anne-Sophie Chauvin
- Group
of Coordination Chemistry, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL, CH-1015 Lausanne, Switzerland
| | - Georges Menzildjian
- Laboratory
of Magnetic Resonance, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sergei Kuzin
- Laboratory
of Physical Chemistry, Department of Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Maxim Yulikov
- Laboratory
of Physical Chemistry, Department of Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Gunnar Jeschke
- Laboratory
of Physical Chemistry, Department of Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Anne Lesage
- Centre
de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France
| | - Marinella Mazzanti
- Group
of Coordination Chemistry, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL, CH-1015 Lausanne, Switzerland
| | - Lyndon Emsley
- Laboratory
of Magnetic Resonance, Institut des Sciences et Ingénierie
Chimiques, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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