1
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Nano K, Zahariou G, Ioannou PC, Alam MM, Pantazis DA, Raptopoulou CP, Psycharis V, Sanakis Y, Kyritsis P. Electronic properties of the S = 5/2 Mn(II) complexes [Mn{PhC(O)NP(O)PPh2}(N,N)(NO3)], (N,N) = phenanthroline, neocuproine, 2,2′-bipyridine. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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2
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Yao XN, Yang MW, Xiong J, Liu JJ, Gao C, Meng YS, Jiang SD, Wang BW, Gao S. Enhanced magnetic anisotropy in a tellurium-coordinated cobalt single-ion magnet. Inorg Chem Front 2017. [DOI: 10.1039/c6qi00543h] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fine-tuning of the ligand field of a series of four-coordinate Co(ii) SIMs, yielding the first tellurium-coordinated SIM.
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Affiliation(s)
- Xiao-Nan Yao
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Mu-Wen Yang
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Jin Xiong
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Jia-Jia Liu
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Chen Gao
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Yin-Shan Meng
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Shang-Da Jiang
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Bing-Wu Wang
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
| | - Song Gao
- Beijing National Laboratory of Molecular Science
- College of Chemistry and Molecular Engineering
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- Peking University
- Beijing
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3
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Sottini S, Poneti G, Ciattini S, Levesanos N, Ferentinos E, Krzystek J, Sorace L, Kyritsis P. Magnetic Anisotropy of Tetrahedral Co II Single-Ion Magnets: Solid-State Effects. Inorg Chem 2016; 55:9537-9548. [PMID: 27636564 DOI: 10.1021/acs.inorgchem.6b00508] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This study reports the static and dynamic magnetic characterization of two mononuclear tetrahedral CoII complexes, [Co{iPr2P(E)NP(E)iPr2}2], where E = S (CoS4) and Se (CoSe4), which behave as single-ion magnets (SIMs). Low-temperature (15 K) single-crystal X-ray diffraction studies point out that the two complexes exhibit similar structural features in their first coordination sphere, but a disordered peripheral iPr group is observed only in CoS4. Although the latter complex crystallizes in an axial space group, the observed structural disorder leads to larger transverse magnetic anisotropy for the majority of the molecules compared to CoSe4, as confirmed by electron paramagnetic resonance spectroscopy. Static magnetic characterization indicates that both CoS4 and CoSe4 show easy-axis anisotropy, with comparable D values (∼-30 cm-1). Moreover, alternating-current susceptibility measurements on these CoII complexes, magnetically diluted in their isostructural ZnII analogues, highlight the role of dipolar magnetic coupling in the mechanism of magnetization reversal. In addition, our findings suggest that, despite their similar anisotropic features, CoS4 and CoSe4 relax magnetically via different processes. This work provides experimental evidence that solid-state effects may affect the magnetic behavior of SIMs.
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Affiliation(s)
- Silvia Sottini
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit of Florence, University of Florence , via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Giordano Poneti
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit of Florence, University of Florence , via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Samuele Ciattini
- Centro Interdipartimentale di Crystallografia Strutturale CRIST, University of Florence , via della Lastruccia 5, 50019 Sesto Fiorentino, Italy
| | - Nikolaos Levesanos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, GR-15771 Athens, Greece
| | - Eleftherios Ferentinos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, GR-15771 Athens, Greece
| | - J Krzystek
- National High Magnetic Field Laboratory (NHMFL), Florida State University , Tallahassee, Florida 32310, United States
| | - Lorenzo Sorace
- Department of Chemistry "Ugo Schiff" and INSTM Research Unit of Florence, University of Florence , via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens , Panepistimiopolis, GR-15771 Athens, Greece
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4
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Cobalt(II) complexes of organophosphorus ligands with XPNSO skeleton (X = O, S). Solid state structure and solution behavior. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Coordination of iPr2P(O)NHP(O)iPr2 to Co(II): Simultaneous formation of octahedral and tetrahedral complexes. INORG CHEM COMMUN 2013. [DOI: 10.1016/j.inoche.2013.01.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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6
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Grigoropoulos A, Maganas D, Symeonidis D, Giastas P, Cowley AR, Kyritsis P, Pneumatikakis G. Synthesis of Chalcogenidoimidodiphosphinato–Rh
I
Complexes and DFT Investigation of Their Catalytic Activation in Olefin Hydroformylation. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200921] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexios Grigoropoulos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Dimitrios Maganas
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
- Max‐Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios Symeonidis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Petros Giastas
- Laboratory of Structural and Supramolecular Chemistry, NCSR “Demokritos”, Agia Paraskevi 15310, Athens, Greece
| | - Andrew R. Cowley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
| | - Georgios Pneumatikakis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 15771, Athens, Greece, Fax: +30‐210‐7274782, http://www.chem.uoa.gr/
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7
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Mathies G, Chatziefthimiou SD, Maganas D, Sanakis Y, Sottini S, Kyritsis P, Groenen EJJ. High-frequency EPR study of the high-spin FeII complex Fe[(SPPh2)2N]2. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:94-100. [PMID: 23064483 DOI: 10.1016/j.jmr.2012.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 06/01/2023]
Abstract
We report continuous-wave electron-paramagnetic-resonance (EPR) spectra of the high-spin Fe(II) complex Fe[(SPPh(2))(2)N](2) at 275.7 GHz, 94.1 GHz and 9.5 GHz. Combined analysis of these EPR spectra shows that the complex occurs in multiple conformations. For two main conformations the spin-Hamiltonian parameters, which reflect the electronic structure of the complex, are accurately determined: (1) D=9.17 cm(-1) (275 GHz), E/D=0.021 and (2) D=8.87 cm(-1) (266 GHz), E/D=0.052. The EPR spectra obtained at 275.7 GHz on single crystals of the complex are essential for the analysis and in addition they reveal that the two main conformations occur at two magnetically distinguishable sites.
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Affiliation(s)
- Guinevere Mathies
- Huygens Laboratory, Department of Molecular Physics, Leiden University, Leiden, The Netherlands
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8
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Mathies G, Almeida RM, Gast P, Moura JJG, Groenen EJJ. Multifrequency EPR study of Fe3+ and Co2+ in the active site of desulforedoxin. J Phys Chem B 2012; 116:7122-8. [PMID: 22612627 DOI: 10.1021/jp3025655] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The understanding of the electronic structure of S > 1/2 transition-metal sites that show a large zero-field splitting (ZFS) of the magnetic sublevels benefits greatly from study by electron-paramagnetic-resonance (EPR) spectroscopy at frequencies above the standard 9.5 GHz. However, high-frequency EPR spectroscopy is technically challenging and still developing. Particularly the sensitivity of high-frequency EPR spectrometers is often too low to apply the technique in the study of transition-metal sites in proteins and enzymes. Here we report a multifrequency EPR study (at 9.5, 94.9, and 275.7 GHz) of the active site of the protein desulforedoxin, both in its natural Fe(3+) form and substituted with Co(2+). The 275.7 GHz EPR spectra made it possible to determine the ZFS parameters of the Fe(3+) site with high precision. No 275.7 GHz spectrum could be observed of the Co(2+) site, but based on 9.5 GHz spectra, its ZFS parameters could be estimated. We find that the typical variation in the geometry of the active site of a protein or enzyme, referred to as conformational strain, does not only make the detection of EPR spectra challenging, but also their analysis. Comparison of the EPR results on the active site of desulforedoxin to those of the closely related active site of rubredoxin illustrates the necessity of explicit quantum-chemical calculations in order to interrelate the electronic and geometric structure of biological transition-metal sites.
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Affiliation(s)
- Guinevere Mathies
- Department of Physics, Huygens Laboratory, Leiden University, The Netherlands
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9
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Inhibitory activity of the novel Zn[(OPPh2)(SePPh2)N]2 complex towards the Platelet Activating Factor (PAF) and thrombin: Comparison with its isomorphous Co(II) and Ni(II) analogues. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.08.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Maganas D, Sottini S, Kyritsis P, Groenen EJJ, Neese F. Theoretical Analysis of the Spin Hamiltonian Parameters in Co(II)S4 Complexes, Using Density Functional Theory and Correlated ab initio Methods. Inorg Chem 2011; 50:8741-54. [DOI: 10.1021/ic200299y] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Dimitrios Maganas
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-15771 Athens, Greece
- Institute of Theoretical and Physical Chemistry, Wegelerstrasse 12, D-53115 Bonn, Germany
| | - Silvia Sottini
- Department of Molecular Physics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-15771 Athens, Greece
| | - Edgar J. J. Groenen
- Department of Molecular Physics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Frank Neese
- Institute of Theoretical and Physical Chemistry, Wegelerstrasse 12, D-53115 Bonn, Germany
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11
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Gessmann R, Kyvelidou C, Papadovasilaki M, Petratos K. The crystal structure of cobalt-substituted pseudoazurin from Alcaligenes faecalis. Biopolymers 2010; 95:202-7. [DOI: 10.1002/bip.21553] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Maganas D, Grigoropoulos A, Staniland SS, Chatziefthimiou SD, Harrison A, Robertson N, Kyritsis P, Neese F. Tetrahedral and square planar Ni[(SPR(2))(2)N](2) complexes, R = Ph & (i)Pr revisited: experimental and theoretical analysis of interconversion pathways, structural preferences, and spin delocalization. Inorg Chem 2010; 49:5079-93. [PMID: 20462270 DOI: 10.1021/ic100163g] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulfur-containing mono- or bidentate types of ligands, usually form square planar Ni((II))S(4) complexes. However, it has already been established that the bidentate L(-) dithioimidodiphosphinato ligands, [R(2)P(S)NP(S)R'(2)](-), R, and R' = aryl or alkyl, can afford both tetrahedral and square planar, NiS(4)-containing, homoleptic Ni(R,R')L(2) complexes, owing to an apparent structural flexibility, which has not, so far, been probed. In this work, the literature tetrahedral Ni[R(2)P(S)NP(S)R(2)](2) complexes, R = Ph (Ni(Ph,Ph)L(2), 1(Td)) and R = (i)Pr (Ni(iPr,iPr)L(2), 2) as well as the newly synthesized Ni[(i)Pr(2)P(S)NP(S)Ph(2)](2) complex (Ni(iPr,Ph)L(2), 3), have been studied by UV-vis, IR, and (31)P NMR spectroscopy. Complex 3 was shown by X-ray crystallography to be square planar, and magnetic studies confirmed that it is diamagnetic in the solid state. However, it becomes paramagnetic in solution, as it shows a similar UV-vis spectrum to one of the tetrahedral 1(Td) and 2 complexes. The crystal structure of the potassium salt of the asymmetric ligand, [(i)Pr(2)P(S)NP(S)Ph(2)]K, has also been determined and compared to those of the protonated (i)Pr(2)P(S)NHP(S)Ph(2) ligand and complex 3. All three, 1(Td), 2, and 3, Ni(R,R')L(2) complexes show strong paramagnetic effects in their solution (31)P NMR spectra. The magnetic properties of paramagnetic complexes 1 and 2 in the solid state were investigated on oriented crystals, and their analysis afforded remarkably small values of the spin-orbit coupling constant (lambda) and orbital reduction factor (k) parameters, implying significant delocalization of unpaired electronic density toward the ligands. The above experimental findings are combined with data from standard density functional theory and correlated multiconfiguration ab initio theoretical methods, in an effort to investigate the interplay between the square planar and tetrahedral geometries of the NiS(4) core, the mechanistic pathway for the spin-state interconversion, the degree of covalency of the Ni-S bonds, and the distribution of the spin density in this type of system. The analysis provides justification for the structural flexibility of such ligands, affording Ni(R,R')L(2) complexes with variable metallacycle conformation and NiS(4) core geometries. Of particular importance are the large zero-field splitting values estimated by both experimental and theoretical means, which have not, as yet, been verified by direct methods, such as electron paramagnetic resonance spectroscopy. The findings of our work confirm earlier observations on the feasibility of synthesizing either tetrahedral or square planar NiS(4) complexes containing the same type of ligands. They can also form the basis of investigating structure-properties relationships in other NiS(4)-containing systems.
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Affiliation(s)
- Dimitrios Maganas
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-157 71 Athens, Greece
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13
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Maganas D, Milikisyants S, Rijnbeek JMA, Sottini S, Levesanos N, Kyritsis P, Groenen EJJ. A Multifrequency High-Field Electron Paramagnetic Resonance Study of CoIIS4 Coordination. Inorg Chem 2009; 49:595-605. [DOI: 10.1021/ic901911h] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dimitrios Maganas
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-15771 Athens, Greece
| | - Sergey Milikisyants
- Department of Molecular Physics, Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Jorrit M. A. Rijnbeek
- Department of Molecular Physics, Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Silvia Sottini
- Department of Molecular Physics, Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
| | - Nikolaos Levesanos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-15771 Athens, Greece
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, GR-15771 Athens, Greece
| | - Edgar J. J. Groenen
- Department of Molecular Physics, Huygens Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden, The Netherlands
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