1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Naz Z, Moin ST, Hofer TS. Hydration of Closely Related Manganese and Magnesium Porphyrins in Aqueous Solutions: Ab Initio Quantum Mechanical Charge Field Molecular Dynamics Simulation Study. J Phys Chem B 2019; 123:10769-10779. [PMID: 31738566 DOI: 10.1021/acs.jpcb.9b07639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To the best of our knowledge, the current study based on ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) is the first to explore the difference in the hydration behavior between Mn(II)- and Mg(II)-associated porphyrins (Mn(II)-POR and Mg(II)-POR) in aqueous solution. The simulation study highlights similar and dissimilar characteristics of the structural, dynamical, and thermodynamical properties of these closely related metals bound to porphyrins in aqueous solution. The structural analysis is based on radial and angular distribution functions, coordination number distributions, and angular-radial distributions. Both hydrated systems demonstrate similar pentacoordinated structures formed via the axial coordination of one water molecule to the metal ion in addition to the four nitrogen atoms of the porphyrin ring. However, in the case of Mn(II)-POR, the formation of a distorted square pyramidal geometry was observed. It was envisaged as a weak coordination of the water molecule to the Mn(II) atom and thus higher atomic fluctuation for all atoms in contrast to that for the hydrated Mg(II)-POR. The dynamical data in terms of the mean residence times, velocity autocorrelation function, free energy, and other parameters revealed the difference in the metal binding effect because the Mn(II) atom was observed to inhibit H-bond formation more than the presence of Mg(II) atoms in the core of the porphyrin. The current study thus highlights the significant differences in the structural and dynamical properties of Mn(II)- and Mg(II)-associated porphyrin systems.
Collapse
Affiliation(s)
- Zobia Naz
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences , University of Karachi , Karachi 75270 , Pakistan
| | - Syed Tarique Moin
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences , University of Karachi , Karachi 75270 , Pakistan
| | - Thomas S Hofer
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| |
Collapse
|
3
|
Orzeł Ł, Polaczek J, Procner M. Review: Recent advances in the investigations of NO activation on cobalt and manganese porphyrins: a brief review. J COORD CHEM 2015. [DOI: 10.1080/00958972.2015.1068303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Łukasz Orzeł
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland
| | | | | |
Collapse
|
4
|
Terranova U, de Leeuw NH. Aqueous Fe2S2 cluster: structure, magnetic coupling, and hydration behaviour from Hubbard U density functional theory. Phys Chem Chem Phys 2015; 16:13426-33. [PMID: 24881882 DOI: 10.1039/c4cp00984c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We present a DFT + U investigation of the all-ferrous Fe2S2 cluster in aqueous solution. We determine the value of U by tuning the geometry of the cluster in the gas-phase to that obtained by the highly accurate CCSD(T) method. When the optimised value of U is employed for the aqueous Fe2S2 cluster (Fe2S2(aq)), the resulting geometry agrees well with the X-ray diffraction structure, while the magnetic coupling is in line with the estimate from Mössbauer data. Molecular dynamics trajectories predict Fe2S2(aq) to be stable in water, regardless of the introduction of U. However, significant differences arise in the geometry, hydration, and exchange constant of the solvated clusters.
Collapse
Affiliation(s)
- Umberto Terranova
- Department of Chemistry, University College London, London, WC1H 0AJ, UK.
| | | |
Collapse
|
5
|
Cuya Guizado TR, Louro SRW, Anteneodo C. Hydration of hydrophobic biological porphyrins. J Chem Phys 2011; 134:055103. [PMID: 21303163 DOI: 10.1063/1.3544376] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Explicit solvent, single solute molecular dynamics simulations of protoporphyrin IX and its Fe(2+) complex (heme) in water were performed. The relation of solute-solvent was examined through the spatial distribution functions of water molecules around the centroid of the porphyrin ring. A detailed description of the time-averaged structure of water surrounding the solutes as well as of its fluctuations is presented.
Collapse
|
6
|
Leung K, Nielsen IMB, Sai N, Medforth C, Shelnutt JA. Cobalt-porphyrin catalyzed electrochemical reduction of carbon dioxide in water. 2. Mechanism from first principles. J Phys Chem A 2011; 114:10174-84. [PMID: 20726563 DOI: 10.1021/jp1012335] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We apply first principles computational techniques to analyze the two-electron, multistep, electrochemical reduction of CO(2) to CO in water using cobalt porphyrin as a catalyst. Density functional theory calculations with hybrid functionals and dielectric continuum solvation are used to determine the steps at which electrons are added. This information is corroborated with ab initio molecular dynamics simulations in an explicit aqueous environment which reveal the critical role of water in stabilizing a key intermediate formed by CO(2) bound to cobalt. By use of potential of mean force calculations, the intermediate is found to spontaneously accept a proton to form a carboxylate acid group at pH < 9.0, and the subsequent cleavage of a C-OH bond to form CO is exothermic and associated with a small free energy barrier. These predictions suggest that the proposed reaction mechanism is viable if electron transfer to the catalyst is sufficiently fast. The variation in cobalt ion charge and spin states during bond breaking, DFT+U treatment of cobalt 3d orbitals, and the need for computing electrochemical potentials are emphasized.
Collapse
Affiliation(s)
- Kevin Leung
- MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | | | | | | | | |
Collapse
|
7
|
Jiao D, Leung K, Rempe SB, Nenoff TM. First Principles Calculations of Atomic Nickel Redox Potentials and Dimerization Free Energies: A Study of Metal Nanoparticle Growth. J Chem Theory Comput 2010; 7:485-95. [DOI: 10.1021/ct100431m] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dian Jiao
- Nanobiology Department, MS 0895, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States, and Surface and Interface Sciences Department, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Kevin Leung
- Nanobiology Department, MS 0895, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States, and Surface and Interface Sciences Department, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Susan B. Rempe
- Nanobiology Department, MS 0895, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States, and Surface and Interface Sciences Department, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Tina M. Nenoff
- Nanobiology Department, MS 0895, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States, and Surface and Interface Sciences Department, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| |
Collapse
|
8
|
Cramer CJ, Truhlar DG. Density functional theory for transition metals and transition metal chemistry. Phys Chem Chem Phys 2009; 11:10757-816. [PMID: 19924312 DOI: 10.1039/b907148b] [Citation(s) in RCA: 1079] [Impact Index Per Article: 71.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We introduce density functional theory and review recent progress in its application to transition metal chemistry. Topics covered include local, meta, hybrid, hybrid meta, and range-separated functionals, band theory, software, validation tests, and applications to spin states, magnetic exchange coupling, spectra, structure, reactivity, and catalysis, including molecules, clusters, nanoparticles, surfaces, and solids.
Collapse
Affiliation(s)
- Christopher J Cramer
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431, USA.
| | | |
Collapse
|
9
|
Leung K, Rempe SB, von Lilienfeld OA. Ab initio molecular dynamics calculations of ion hydration free energies. J Chem Phys 2009; 130:204507. [PMID: 19485457 PMCID: PMC2736677 DOI: 10.1063/1.3137054] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 04/25/2009] [Indexed: 11/14/2022] Open
Abstract
We apply ab initio molecular dynamics (AIMD) methods in conjunction with the thermodynamic integration or "lambda-path" technique to compute the intrinsic hydration free energies of Li(+), Cl(-), and Ag(+) ions. Using the Perdew-Burke-Ernzerhof functional, adapting methods developed for classical force field applications, and with consistent assumptions about surface potential (phi) contributions, we obtain absolute AIMD hydration free energies (DeltaG(hyd)) within a few kcal/mol, or better than 4%, of Tissandier et al.'s [J. Phys. Chem. A 102, 7787 (1998)] experimental values augmented with the SPC/E water model phi predictions. The sums of Li(+)/Cl(-) and Ag(+)/Cl(-) AIMD DeltaG(hyd), which are not affected by surface potentials, are within 2.6% and 1.2 % of experimental values, respectively. We also report the free energy changes associated with the transition metal ion redox reaction Ag(+)+Ni(+)-->Ag+Ni(2+) in water. The predictions for this reaction suggest that existing estimates of DeltaG(hyd) for unstable radiolysis intermediates such as Ni(+) may need to be extensively revised.
Collapse
Affiliation(s)
- Kevin Leung
- Department of Surface and Interface Sciences, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
| | | | | |
Collapse
|