Enhancing SIM behaviour in a mononuclear tetrahedral [Co(N,N′-2-iminopyrrolyl)2] complex

Gomes, Pedro T.; Ferreira, Patrícia S.; Malta, José F.; Bandeira, Nuno A. G.; Allgaier, Alexander; Slageren, Joris van; Paixão, J. A.; Almeida, Manuel; Pereira, Laura C. J.

doi:10.1039/d2cc03511a

Cited by 4 publications

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“…As depicted in Figure , at 300 K, the χ M T value of 1 (3.13 cm 3 ·K mol –1 ) exceeds the spin-only value of 1.875 cm 3 ·K mol –1 expected for a high-spin Co(II) ion with S = 3/2 and g = 2, suggesting a considerable spin–orbit coupling contribution. This χ M T value is comparable to those observed in reported examples involving tetrahedral high-spin Co(II) ion. − Upon cooling, the χ M T value gradually decreases until 140 K, below which it decreases rapidly to 2.37 cm 3 ·K mol –1 at 2 K. The final sharp decline at low temperatures is likely attributable to the strong zero-field splitting in 1 . The low-temperature magnetization measurements were performed at different applied magnetic fields ranging from 0 to 7 T at 1.9, 3.0, and 5.0 K (Figure , inset).…”

Section: Resultssupporting

confidence: 82%

“…It should be noted that they usually feature four identical donors. Those zero-field Co(II)-based SIMs with the CoX 4 moiety (X = O, S, Se, Te, − N − ) are summarized in Table S1. In the case of four-coordinate Co(II)-SIMs, great efforts have been dedicated to investigating the underlying factors that govern the magnetic anisotropy and relaxations.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core

Cui,

Xu,

Zhang

et al. 2024

Inorg. Chem.

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A mononuclear four-coordinate Co(II) complex with a [Co II O 4 ] core, namely, PPN[Li(MeOH) 4 ][Co(L) 2 ] (1) (PPN = bis(phosphoranediyl)iminium; H 2 L = perfluoropinacol), has been studied by X-ray crystallography, magnetic characterization, and theoretical calculations. This complex presents a severely distorted coordination geometry. The O−Co−O bite angle is 83.42°/ 83.65°, and the dihedral twist angle between the O−Co−O chelate planes is 55.6°. The structural distortion results in a large easy-axis magnetic anisotropy with D = −104(1) cm −1 and a transverse component with |E| = +4(2) cm −1 . Alternating current (ac) susceptibility measurements demonstrate that 1 exhibits slow relaxation of magnetization at zero static field. However, the frequency-dependent out-of-phase (χ" M ) susceptibilities of 1 at 0 Oe do not show a characteristic maximum. Upon the application of a dc field or the dilution with a diamagnetic Zn matrix, the quantum tunneling of magnetization (QTM) process can be successfully suppressed. Notably, after dilution with the Zn matrix, the obtained sample exhibits a structure different from that of the pristine complex. In this altered sample, the asymmetric unit does not contain the Li(MeOH) 4 + cation, resulting in an O−Co−O bite angle of 86.05°and a dihedral twist angle of 75.84°, thereby leading to an approximate D 2d symmetry. Although such differences are not desirable for magnetic studies, this study still gives some insights. Theoretical calculations reveal that the D parameter is governed by the O−Co−O bite angle, in line with our previous report for other tetrahedral Co(II) complex with a [Co II N 4 ] core. On the other hand, the rhombic component is found to increase as the dihedral angle deviates from 90°. These findings provide valuable guidelines for fine-tuning the magnetic properties of Co(II) complexes.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core

Cui,

Xu,

Zhang

et al. 2024

Inorg. Chem.

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“…The 5-substituted-2-iminopyrrolyl potassium salts KLa–c and KLe , 35,37 c complex 1-H 29 and [Cu(NCMe) 4 ]BF 4 42 were prepared as described in the literature (or slightly adapted from those procedures). The syntheses and characterization data of the potassium salt KLd and its precursors are presented in the ESI †…”

Section: Methodsmentioning

confidence: 99%

“…In one aspect, some B( iii ) complexes have been prepared, characterized and studied as components of emissive layers in light emitting diodes. 31 On the other hand, we have also reported several molecular systems with Mn, 32 Fe 33,34 and Co, 33,35,36 and with Ni 37 with applications in catalysis (as catalysts for hydrosilylation and hydroboration, and for oligo-/polymerization) and in magnetism (as single-ion magnets, i.e. SIMs), respectively.…”

Section: Introductionmentioning

confidence: 97%

New copper(i) complexes of bulky 5-substituted-2-iminopyrrolyl ligands as catalysts for azide–alkyne cycloaddition

et al. 2023

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The role of 2‐iminopyrrolyl copper(I) complexes in the Reversible‐Deactivation Radical Polymerization of methyl methacrylate

de Matos,

Cruz,

Lemos

et al. 2023

Applied Organom Chemis

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The role of 2‐iminopyrrolyl copper(I) complexes in the Reversible‐Deactivation Radical Polymerization (RDRP) of methyl methacrylate (MMA) is described. Mononuclear 2‐iminopyrrolyl copper(I) complexes [Cu{κ2N,N′‐NC4H3‐2‐C(H)=NR′}Ln] 1–7 (R′ = C6H5, Ln = (PPh3)2 (1); R′ = 2,6‐Me2C6H3, Ln = (PPh3)2 (2); R′ = 2,6‐iPr2C6H3, Ln = (PPh3)2 (3); R′ = 4‐NMe2C6H4, Ln = (PPh3)2 (4); R′ = CH3, Ln = (PPh3)2 (5); R′ = CH3, Ln = (PMe3)2 (6); R′ = CH3, Ln = PiPr3 (7)) were synthesized by the reaction of the in situ prepared sodium salts of precursors HL1–5 with [Cu(NCMe)4]BF4 with the respective phosphines. In their absence, the binuclear complex [Cu{κN,κN'‐NC4H3‐2‐C(H)=NCH3}]2 8 was formed instead, which, when treated with one equivalent of PR3 yielded the binuclear complexes [Cu2{κN,κN'‐NC4H3‐2‐C(H)=NCH3}2PR3] 9 (R = Ph) and 10 (R = Me).All complexes, except 8, were active in the RDRP of MMA using the initiator tert‐butyl‐α‐bromoisobutyrate (tBiB‐Br), achieving apparent propagation kinetic constants (kp') in the range of 0.5–7.5 × 10−5 s−1, at 90 °C and with a [MMA]0:[complex]0:[tBiB‐Br]0 ratio of 500:1:1. All reactions yielded poly (methyl methacrylate)s with molecular weights () and dispersities higher than expected for Controlled Radical Polymerization processes. Complex 7 achieved the best results, with values being only 1.2‐fold higher than theoretically expected. Experimental and density functional theory (DFT) studies suggest that this system operates via Atom Transfer Radical Polymerization/Organometallic Mediated Radical Polymerization (ATRP/OMRP) mechanisms interplay.

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Enhancing SIM behaviour in a mononuclear tetrahedral [Co(N,N′-2-iminopyrrolyl)₂] complex

Abstract: A new homoleptic Co(II) complex bearing two highly sterically congested 2-formiminopyrrolyl N,N’-chelating ligands is reported, displaying slow relaxation of the magnetisation at zero static (DC) field. This compound shows large...

Cited by 4 publications

References 19 publications

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core

New copper(i) complexes of bulky 5-substituted-2-iminopyrrolyl ligands as catalysts for azide–alkyne cycloaddition

The role of 2‐iminopyrrolyl copper(I) complexes in the Reversible‐Deactivation Radical Polymerization of methyl methacrylate

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Enhancing SIM behaviour in a mononuclear tetrahedral [Co(N,N′-2-iminopyrrolyl)2] complex

Abstract: A new homoleptic Co(II) complex bearing two highly sterically congested 2-formiminopyrrolyl N,N’-chelating ligands is reported, displaying slow relaxation of the magnetisation at zero static (DC) field. This compound shows large...

Cited by 4 publications

References 19 publications

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [CoIIO4] Core

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [CoIIO4] Core

New copper(i) complexes of bulky 5-substituted-2-iminopyrrolyl ligands as catalysts for azide–alkyne cycloaddition

The role of 2‐iminopyrrolyl copper(I) complexes in the Reversible‐Deactivation Radical Polymerization of methyl methacrylate

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Enhancing SIM behaviour in a mononuclear tetrahedral [Co(N,N′-2-iminopyrrolyl)₂] complex

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core

Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co^IIO₄] Core