Tetranuclear Ni(<scp>ii</scp>) and Co(<scp>ii</scp>) Schiff-base complexes with an M<sub>4</sub>O<sub>6</sub> defective dicubane-like core: zero-field SMM behavior in the cobalt analogue

Němec, Ivan; Herchel, Radovan; Machata, Marek; Trávníček, Zdeněk

doi:10.1039/c7nj02281f

Cited by 35 publications

(16 citation statements)

References 97 publications

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“…The bond distances and bond angles relevant to the coordination core of cobalt ions are given in Table S4. planar, μ3-cubic, and μ-pyramidal arrangements at these bridging centers similar to Co and mixedvalenec (Co II /Co III ) complexes [53,[77][78][79][80][81][82][83][84][85]. In 4, a symmetric network of reasonably strong, intermolecular H-bonding interactions (2.765-2.930 Å ) between oxygen atoms (O(9), O(10), O(11)) of the uncoordinated NO3 -ions and the uncoordinated protonated ethanoate oxygen (O(5)) atom in the side arm of the ligand (H2L1 2− ) (O(11)-O(5) = 2.805 Å ), in one tetranuclear unit and the coordinated amino group (NH2) (O(9)-N(2) = 2.930 Å ) and the uncoordinated hydroxy (O8)) of THMAM (O(10)-O(8) = 2.765 Å ) of the neighboring tetranuclear unit, direct the formation of a beautiful 2D-sheet structure (Figure 7).…”

Section: [Co 4 (Hmentioning

confidence: 98%

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

et al. 2020

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The reaction of 2,6-diformyl-4-methylphenol (DFMF) with 1-amino-2-propanol (AP) and tris(hydroxymethyl)aminomethane (THMAM) was investigated in the presence of Cobalt(II) salts, (X = ClO4−, CH3CO2−, Cl−, NO3−), sodium azide (NaN3), and triethylamine (TEA). In one pot, the variation in Cobalt(II) salt results in the self-assembly of dinuclear, tetranuclear, and H-bonding-directed polynuclear coordination complexes of Cobalt(III), Cobalt(II), and mixed-valence CoIICoIII: [Co2III(H2L−1)2(AP−1)(N3)](ClO4)2 (1), [Co4(H2L−1)2(µ3-1,1,1-N3)2(µ-1,1-N3)2Cl2(CH3OH)2]·4CH3OH (2), [Co2IICo2III(HL−2)2(µ-CH3CO2)2(µ3-OH)2](NO3)2·2CH3CH2OH (3), and [Co2IICo2III (H2L12−)2(THMAM−1)2](NO3)4 (4). In 1, two cobalt(III) ions are connected via three single atom bridges; two from deprotonated ethanolic oxygen atoms in the side arms of the ligands and one from the1-amino-2-propanol moiety forming a dinuclear unit with a very short (2.5430(11) Å) Co-Co intermetallic separation with a coordination number of 7, a rare feature for cobalt(III). In 2, two cobalt(II) ions in a dinuclear unit are bridged through phenoxide O and μ3-1,1,1-N3 azido bridges, and the two dinuclear units are interconnected by two μ-1,1-N3 and two μ3-1,1,1-N3 azido bridges generating tetranuclear cationic [Co4(H2L−1)2(µ3-1,1,1-N3)2(µ-1,1-N3)2Cl2(CH3OH)2]2+ units with an incomplete double cubane core, which grow into polynuclear 1D-single chains along the a-axis through H-bonding. In 3, HL2− holds mixed-valent Co(II)/Co(III) ions in a dinuclear unit bridged via phenoxide O, μ-1,3-CH3CO2−, and μ3-OH− bridges, and the dinuclear units are interconnected through two deprotonated ethanolic O in the side arms of the ligands and two μ3-OH− bridges generating cationic tetranuclear [Co2IICo2III(HL−2)2(µ-CH3CO2)2(µ3-OH)2]2+ units with an incomplete double cubane core. In 4, H2L1−2 holds mixed-valent Co(II)/Co(III) ions in dinuclear units which dimerize through two ethanolic O (μ-RO−) in the side arms of the ligands and two ethanolic O (μ3-RO−) of THMAM bridges producing centrosymmetric cationic tetranuclear [Co2IICo2III (H2L1−2)2(THMAM−1)2]4+ units which grow into 2D-sheets along the bc-axis through a network of H-bonding. Bulk magnetization measurements on 2 demonstrate that the magnetic interactions are completely dominated by an overall ferromagnetic coupling occurring between Co(II) ions.

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Section: [Co 4 (Hmentioning

confidence: 98%

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

et al. 2020

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“…Due to this energy barrier, slow magnetic relaxation of magnetization and magnetic hysteresis loops are observed . The specific µ 3 ‐O bridges present in the complex core play an important role in facilitating magnetic exchange interactions between the paramagnetic metal ions in such complexes …”

Section: Introductionmentioning

confidence: 99%

“…[26] The specific μ 3 -O bridges present in the complex core play an important role in facilitating magnetic exchange interactions between the paramagnetic metal ions in such complexes. [27][28][29] Several mixed-metal Schiff base complexes having cubane and defect-dicubane core topologies have been reported. However few complexes of Zn II ions having such topology have been reported.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Characterization of Different Homometallic and Heterobimetallic Complexes of Nickel and Zinc Ions by Controlling Molar Ratios and Solvents

et al. 2019

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This work describes employment of two structurally similar Schiff‐base ligands (H2L and H2L‐Me) [H2L = C14H13NO3 and H2L‐Me = C15H15NO3] for the synthesis of three homo‐metallic ZnII and two hetero‐bimetallic ZnII–NiII based multinuclear complexes {[ZnII4L4(MeOH)2] (1), [ZnII5(L)5(MeOH)2]·MeOH·CH3CN (2), [(L)2ZnII4Cl2(µ3‐OMe)2(MeOH)2]·2MeOH (3), [NiII2ZnII2(L)4(MeOH)2] (4) and [Ni3Zn2(L‐Me)5(H2O)2]·MeOH·CH3CN (5)} with different interesting structural core topologies. All of these complexes (1–5) have been characterized by single‐crystal X‐ray diffraction (XRD), elemental analysis, and UV/Vis and Fourier transform infrared (FTIR) spectroscopy. The fluorescence properties of ZnII‐containing complexes have been studied by measuring fluorescence spectra in solid state and solution phase. The luminescence behavior has been further quantified by fluorescence life‐time and quantum yield measurements. Using high resolution mass spectrometry (HR‐MS), the molecular integrity of complexes in the solution phase has been demonstrated by simulating isotopic distribution of molecules with theoretically calculated molecular isotopic patterns. The magnetic properties of ZnII–NiII containing complexes (4–5) have been studied in the temperature range from 5 K to 300 K. Thermogravimetric analysis (TGA) has been carried out to study the thermal stabilities of these complexes (1–5).

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“…13−16 Numerous compounds based on these divalent Co(II) complexes exhibit single-molecule magnetism. 17−21 Therefore, a large amount of Co(II) complex is designed and synthesized by various methods. According to the relevant principles, chemists have designed and modified ligands, metal ions, and bridging ligands in various ways to facilitate the construction of a wide range of Co(II) single-molecule magnet (SMM).…”

Section: Introductionmentioning

confidence: 99%

Solvent-Induced Structural Diversity and Magnetic Research of Two Cobalt(II) Complexes

Wang

Zhu

et al. 2019

ACS Omega

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The solvent-induced topological and structural diversities of two Co(II) complexes, namely, [Co(L)2(SCN)2] (Co1) and [Co2(L)2(SCN)(OAc)3] (Co2) (L = 8-methoxyquinoline), were comparatively analyzed. Certain proportions of L, Co(OAc)2·4H2O, and NaSCN were mixed and dissolved in CH3OH at 60 °C to obtain complex Co1. Complex Co2, an asymmetric dinuclear compound, was obtained by simply replacing CH3OH with CH3CN as the solvent. The Co(II) ion in complex Co1 was coordinated by the N4O2 mode provided by two L ligands and two SCN– anions. The two Co(II) ions in Co2 were in the N2O4 and NO5 coordination environment and were linked by two μ2-OAc– bridges and one rare μ3-OAc– bridge. Weak interaction analysis revealed that complexes Co1 and Co2 exhibited 6-connected shp and 14-connected fcu nets, respectively. Magnetic studies showed that Co1 demonstrated single-ion magnet behavior under 2000 Oe. These behaviors are indicative of clearly field-induced single-ion magnetic behavior with Ueff = 34.7(2) K and τ0 = 2.7(2) × 10–7 s under 2000 Oe dc field, respectively. By contrast, Co2 lacked frequency dependence under zero-field conditions. Electrospray ionization mass spectrometry indicated that two complexes were stable in N,N-dimethylformamide.

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Tetranuclear Ni(ii) and Co(ii) Schiff-base complexes with an M₄O₆ defective dicubane-like core: zero-field SMM behavior in the cobalt analogue

Abstract: Two tetranuclear Ni4 and Co4 complexes were prepared and characterized. Their magnetic properties were thoroughly studied and it was revealed that the Co4 compound behaves as a zero-field single-molecule magnet.

Cited by 35 publications

References 97 publications

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

Isolation and Characterization of Different Homometallic and Heterobimetallic Complexes of Nickel and Zinc Ions by Controlling Molar Ratios and Solvents

Solvent-Induced Structural Diversity and Magnetic Research of Two Cobalt(II) Complexes

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Tetranuclear Ni(ii) and Co(ii) Schiff-base complexes with an M4O6 defective dicubane-like core: zero-field SMM behavior in the cobalt analogue

Abstract: Two tetranuclear Ni4 and Co4 complexes were prepared and characterized. Their magnetic properties were thoroughly studied and it was revealed that the Co4 compound behaves as a zero-field single-molecule magnet.

Cited by 35 publications

References 97 publications

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

One-Pot Self-Assembly of Dinuclear, Tetranuclear, and H-Bonding-Directed Polynuclear Cobalt(II), Cobalt(III), and Mixed-Valence Co(II)/Co(III) Complexes of Schiff Base Ligands with Incomplete Double Cubane Core

Isolation and Characterization of Different Homometallic and Heterobimetallic Complexes of Nickel and Zinc Ions by Controlling Molar Ratios and Solvents

Solvent-Induced Structural Diversity and Magnetic Research of Two Cobalt(II) Complexes

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Tetranuclear Ni(ii) and Co(ii) Schiff-base complexes with an M₄O₆ defective dicubane-like core: zero-field SMM behavior in the cobalt analogue