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Manu Manohar E, Roy S, Li XL, Tothadi S, Mok JG, Tang J, Herchel R, Lee J, Dey A, Das S. Halide mediated modulation of magnetic interaction and anisotropy in dimeric Co(II) complexes. Dalton Trans 2024; 53:10499-10510. [PMID: 38841816 DOI: 10.1039/d4dt00927d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
The burgeoning interest in the field of molecular magnetism is to perceive the high magnetic anisotropy in different geometries of metal complexes and hence to draw a magneto-structural correlation. Despite a handful of examples to exemplify the magnetic anisotropy in various coordination geometries of mononuclear complexes, the magnetic anisotropies for two different coordination geometries are underexplored. Employing an appropriate synthetic strategy utilizing the ligand LH2 [2,2'-{(1E,1'E)-pyridine2,6-diyl-bis(methaneylylidine)}-bis(azaneylylidine)diphenol] and cobalt halide salts in a 1 : 2 stoichiometric ratio in the presence of triethylamine allowed us to report a new family of dinuclear cobalt complexes [CoII2X2(L)(P)(Q)]·S with varying terminal halides [X = Cl, P = CH3CN, Q = H2O, S = H2O (1), X = Br, P = CH3CN, Q = H2O, S = H2O (2), X = I, P = CH3CN, and Q = CH3CN (3)]. All these complexes are characterized through single crystal X-ray crystallography, which reveals their crystallization in the monoclinic system P21/n space group with nearly identical structural features. These complexes share vital components, including Co(II) centers, a fully deprotonated ligand [L]2-, halide ions, and solvent molecules. The [L]2- ligand contains two Co(II) centers, where phenolate oxygen atoms bridge the Co(II) centers, forming a Co2O2 four-membered ring. Co1 demonstrates a distorted pentagonal-bipyramidal geometry with axial positions for solvent molecules, while Co2 displays a distorted tetrahedral geometry involving phenolate oxygen atoms and halide ions. Temperature-dependent dc magnetic susceptibility measurements were conducted on 1-3 within a range of 2 to 300 K at 1 kOe. The χmT vs. T plots exhibit similar trends, with χmT values at 300 K higher than the spin-only value, signifying a significant orbital contribution. As the temperature decreases, χmT decreases smoothly in all the complexes; however, no clear saturation at low temperatures is observed. Field-dependent magnetization measurements indicate a rapid increase below 20 kOe, with no hysteresis and a low magnetic blocking temperature. DFT and CASSCF/NEVPT2 theoretical calculations were performed to perceive the magnetic interaction and single-ion anisotropies of Co(II) ions in various ligand-field environments.
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Affiliation(s)
- Ezhava Manu Manohar
- Department of Basic Sciences, Chemistry Discipline, Institute of Infrastructure Technology Research and Management, Near Khokhra Circle, Maninagar East, Ahmedabad-380026, Gujarat, India.
| | - Soumalya Roy
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
| | - Xiao-Lei Li
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China.
| | - Srinu Tothadi
- Analytical and Environmental Sciences Division and Centralized Instrumentation Facility, CSIR-Central Salt and Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, India
| | - Jun-Gwi Mok
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China.
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 77900 Olomouc, Czech Republic.
| | - Junseong Lee
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
| | - Atanu Dey
- Department of Chemistry, Gandhi Institute of Technology and Management (GITAM), NH 207, Nagadenehalli, Doddaballapur Taluk, Bengaluru, 561203 Karnataka, India.
| | - Sourav Das
- Department of Basic Sciences, Chemistry Discipline, Institute of Infrastructure Technology Research and Management, Near Khokhra Circle, Maninagar East, Ahmedabad-380026, Gujarat, India.
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Manohar EM, Dhandapani HN, Roy S, Pełka R, Rams M, Konieczny P, Tothadi S, Kundu S, Dey A, Das S. Tetranuclear Co II4O 4 Cubane Complex: Effective Catalyst Toward Electrochemical Water Oxidation. Inorg Chem 2024; 63:4883-4897. [PMID: 38494956 DOI: 10.1021/acs.inorgchem.3c03956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The reaction of Co(OAc)2·6H2O with 2,2'-[{(1E,1'E)-pyridine-2,6-diyl-bis(methaneylylidene)bis(azaneylylidene)}diphenol](LH2) a multisite coordination ligand and Et3N in a 1:2:3 stoichiometric ratio forms a tetranuclear complex Co4(L)2(μ-η1:η1-OAc)2(η2-OAc)2]· 1.5 CH3OH· 1.5 CHCl3 (1). Based on X-ray diffraction investigations, complex 1 comprises a distorted Co4O4 cubane core consisting of two completely deprotonated ligands [L]2- and four acetate ligands. Two distinct types of CoII centers exist in the complex, where the Co(2) center has a distorted octahedral geometry; alternatively, Co(1) has a distorted pentagonal-bipyramidal geometry. Analysis of magnetic data in 1 shows predominant antiferromagnetic coupling (J = -2.1 cm-1), while the magnetic anisotropy is the easy-plane type (D1 = 8.8, D2 = 0.76 cm-1). Furthermore, complex 1 demonstrates an electrochemical oxygen evolution reaction (OER) with an overpotential of 325 mV and Tafel slope of 85 mV dec-1, required to attain a current density of 10 mA cm-2 and moderate stability under alkaline conditions (pH = 14). Electrochemical impedance spectroscopy studies reveal that compound 1 has a charge transfer resistance (Rct) of 2.927 Ω, which is comparatively lower than standard Co3O4 (5.242 Ω), indicating rapid charge transfer kinetics between electrode and electrolyte solution that enhances higher catalytic activity toward OER kinetics.
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Affiliation(s)
- Ezhava Manu Manohar
- Department of Basic Sciences, Chemistry Discipline, Institute of Infrastructure, Technology, Research, and Management, Near Khokhra Circle, Maninagar East, Ahmedabad, Gujarat 380026, India
| | - Hariharan N Dhandapani
- Electrochemical Process Engineering (EPE) Division, CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi, Tamil Nadu 630003, India
| | - Soumalya Roy
- Department of Basic Sciences, Chemistry Discipline, Institute of Infrastructure, Technology, Research, and Management, Near Khokhra Circle, Maninagar East, Ahmedabad, Gujarat 380026, India
| | - Robert Pełka
- Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, Krakow PL-31342, Poland
| | - Michał Rams
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, Kraków 30348, Poland
| | - Piotr Konieczny
- Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, Krakow PL-31342, Poland
| | - Srinu Tothadi
- Analytical and Environmental Sciences Division and Centralized Instrumentation Facility, CSIR-Central Salt and Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, India
| | - Subrata Kundu
- Electrochemical Process Engineering (EPE) Division, CSIR-Central Electrochemical Research Institute (CECRI), Karaikudi, Tamil Nadu 630003, India
| | - Atanu Dey
- Department of Chemistry, Gandhi Institute of Technology and Management (GITAM), NH 207, Nagadenehalli, Doddaballapur Taluk, Bengaluru, Karnataka 561203, India
| | - Sourav Das
- Department of Basic Sciences, Chemistry Discipline, Institute of Infrastructure, Technology, Research, and Management, Near Khokhra Circle, Maninagar East, Ahmedabad, Gujarat 380026, India
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Macek L, Bellamy JC, Faber K, Milson CR, Landee CP, Dickie DA, Turnbull MM. Transition metal halide complexes of 4′-aminoacetophenone: Syntheses, structures, and magnetic behavior. Polyhedron 2023. [DOI: 10.1016/j.poly.2022.116214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Koizumi Y, Yonesato K, Yamaguchi K, Suzuki K. Ligand-Protecting Strategy for the Controlled Construction of Multinuclear Copper Cores within a Ring-Shaped Polyoxometalate. Inorg Chem 2022; 61:9841-9848. [PMID: 35737939 DOI: 10.1021/acs.inorgchem.2c01029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ring-shaped polyoxometalate (POM) [P8W48O184]40- contains a large cavity and is an attractive inorganic multidentate ligand for accumulating metal cations. Until now, several multinuclear metal cores are constructed within the {P8W48} framework in aqueous solvents. However, it is still challenging to control the number and arrangement of introduced metal cations because of the numerous coordination sites inside the {P8W48} framework. In this study, we developed a novel approach for the selective synthesis of several multinuclear copper-containing ring-shaped POMs in organic solvents using methoxy groups as organic protecting ligands for the reactive coordination sites. Reacting a tetra-n-butylammonium (TBA) salt of [P8W48O184]40- (P8W48) with 4 and 8 equiv of copper(II) acetate in the presence of methanol (MeOH), tetra- and octacopper cores were incorporated into the cavity to form TBA11H13[Cu4(H2O)4P8W48O176(OCH3)8]·28H2O·3CH3NO2 (Cu4) and TBA14H2[Cu8(H2O)12P8W48O176(OCH3)8]·24H2O·CH3CN (Cu8), respectively. For both structures, methoxy groups served as protecting ligands and temporarily inactivated vacant coordination sites. Without MeOH, dodeca- and hexadecacopper cores were constructed inside the cavity to form TBA14H2[Cu12(H2O)16P8W48O184]·4H2O (Cu12) and TBA16H8[Cu16(OH)16(H2O)4P8W48O184]·12H2O·C3H6O (Cu16), respectively. The arrangement of copper ions on the same {P2W12} units could be controlled by the input number of copper ions. Moreover, all four POMs could be synthesized from P8W48 by the stepwise addition of 4 equiv of copper(II) acetate, clarifying the introduction process.
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Affiliation(s)
- Yoshihiro Koizumi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kentaro Yonesato
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kazuya Yamaguchi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kosuke Suzuki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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