Structural, optical and magnetic properties of a new metal-organic CoII-based complex

A mononuclear cobalt(ii) complex [C5H8N3]2[CoCl4(C5H7N3)2] (I) was synthesized and structurally characterized. Single crystal X-ray diffraction analysis indicates that monometallic Co(ii) ions acted as coordination nodes in a distorted octahedral geometry, giving rise to a supramolecular architecture. The latter is made up of a ½ unit form composed of an anionic element [Co0.5Cl2(C5H7N3)]- and one 2-amino-4-methylpyrimidinium cation [C5H8N3]+. The crystalline arrangement of this compound adopts the sandwich form where inorganic parts are sandwiched between the organic sheets following the [100] direction. More information regarding the structure hierarchy has been supplied based on Hirshfeld surface analysis; the X⋯H (X = N, Cl) interactions play a crucial role in stabilizing the self-assembly process of I, complemented by the intervention of π⋯π electrostatic interaction created between organic entities. Thermal analyses were carried out to study the thermal behavior process. Static magnetic measurements and ab initio calculations of compound I revealed the easy-axis anisotropy character of the central Co(ii) ion. Two-channel field-induced slow-magnetic relaxation was observed; the high-frequency channel is characterized by underbarrier relaxation with U eff = 16.5 cm-1, and the low-frequency channel involves a direct relaxation process affected by the phonon-bottleneck effect.

Influence of the phonon-bottleneck effect and low-energy vibrational modes on the slow spin-phonon relaxation in Kramers-ions-based Cu(II) and Co(II) complexes with 4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole and dicyanamide

Two new complexes, bis-[4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole-κ2N2,N6]bis-(dicyanamide-κN8)copper(II), [Cu(abpt)2(dca)2] (1) and bis-[4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole-κ2N2,N6]bis-(dicyanamide-κN8)cobalt(II), [Co(abpt)2(dca)2] (2), have been prepared and magneto-structurally characterised. Single crystal studies of both complexes have shown that their crystal structures are molecular, in which the central atoms are six-coordinated in the form of a distorted octahedron by two bidentate abpt and two monodentate dca ligands. Even if both complexes have the same composition and crystallize in the same P1̄ space group, they are not isostructural. Both structures contain strong intermolecular N-H⋯N hydrogen bonds and π-π stacking interactions. IR spectra are consistent with the solved structures of both complexes and confirmed the terminal character of the dca ligands and the bidentate coordination of the abpt ligands. The analysis of the magnetic properties showed that both complexes exhibit field-induced slow spin-phonon relaxation. In both complexes, the slow spin-phonon relaxation is influenced by a severe phonon-bottleneck effect that affects the direct process, a dominant relaxation mechanism at low temperatures in both complexes. The phonon-bottleneck effect in 1 was suppressed by simply reducing the crystallite size, and further analysis of the field dependence of the relaxation time yielded the characteristic energy of vibrational modes of 11 cm-1 participating in the Raman process at low magnetic fields. The analysis of magnetic properties and ab initio calculations confirmed that 2 represents a system with a moderate uniaxial anisotropy yielding an average energy barrier of 82 cm-1 (from all four nonequivalent Co(II) sites in the structure of 2).

Single-Molecule Magnetism in Linear Fe(I) Complexes with Aufbau and Non-Aufbau Ground States

With the ongoing efforts on synthesizing mononuclear single-ion magnets (SIMs) with promising applications in high-density data storage and spintronics devices, the linear or quasi-linear Fe(I) complexes emerge as the enticing candidates possessing large unquenched angular momentum. Herein, we have studied five experimentally synthesized linear Fe(I) complexes to uncover the origin of single-molecule magnetic behavior of these complexes. To begin with, we benchmarked the methodology on the experimentally and theoretically well-studied complex [Fe(C(SiMe₃)₃)₂]^-1 (1) (SiMe₃ = trimethylsilyl), which is characterized with a large spin-reversal barrier of 226 cm^-1. Subsequently, the spin-phonon coupling coefficients are calculated for the low-frequency vibrational modes to understand the relaxation mechanism of the complex. Furthermore, the two Fe(I) complexes, that is, [Fe(cyIDep)₂]⁺¹ (2) (cyIDep = 1,3-bis(2',6'-diethylphenyl)-4,5-(CH₂)₄-imidazole-2-ylidene) and [Fe(sIDep)₂]⁺¹ (3) (sIDep = 1,3-bis(2',6'-diethylphenyl)-imidazolin-2-ylidene), are studied that are experimentally reported with no SIM behavior under ac or dc magnetic fields; however, they exhibit large opposite axial zero field splitting (-62.4 and +34.0 cm^-1, respectively) from ab initio calculations. We have unwrapped the origin of this contrasting observation between experiment and theory by probing their magnetic relaxation pathways and the pattern of d orbital splitting. Additionally, the two experimentally synthesized Fe(I) complexes, that is, [(η⁶-C₆H₆)FeAr*-3,5-Pr₂ⁱ] (4) (Ar*-3,5-Pr₂ⁱ = C₆H-2,6-(C₆H₂-2,4,6-Pr₃ⁱ)₂-3,5-Pr₂ⁱ) and [(CAAC)₂Fe]⁺¹ (5) (CAAC = cyclic (alkyl) (amino)carbene), are investigated for SIM behavior, since there is no report on their magnetic anisotropy. To this end, complex 4 presents itself as the possible candidate for SIM.

Modulation of the architectures and magnetic dynamics in pseudotetrahedral cobalt(II) complexes

Two β-Diketiminate cobalt(II) compounds of formula [LCo(μ-Cl)]2∙2C6H14 (1) and [LCoClPy]∙0.5C7H8∙0.5C6H14 (2) (L = [PhC-(PhCN-Dip)2]−, Dip = 2,6-iPr2C6H3) have been synthesized and structurally characterized by single crystal X-ray diffraction. Compound 1...

Synthesis, structure, magnetic properties and thermal behaviour of Ba–MII (MII = Mn, Co, Cu, and Zn) allylmalonates

A series of Ba-MII complexes with allylmalonic acid anions [BaMII(Amal)2(H2O)3]n (MII = Mn, Co, Cu, and Zn) were synthesized. The magnetic measurements revealed slow magnetic relaxation in non-zero field (HDC = 1500 Oe) for CoII ions.

Large easy-axis magnetic anisotropy in a series of trigonal prismatic mononuclear cobalt (II) complexes with zero-field hidden single-molecule magnet behaviour: The important role of the distortion of the coordination sphere and intermolecular interactions on the slow relaxation

The complexes [Co(L)]X·S (X = CoCl42- , S = CH3CN (1); X = ZnCl42- , S = CH3OH (2)), [Co(L)]X2·S (X = ClO4-, S = 2CH3OH (3) and X =...

Field-induced single-ion magnets exhibiting tri-axial anisotropy in a 1D Co(II) coordination polymer with a rigid ligand 4,4'-(buta-1,3-diyne-1,4-diyl)dibenzoate

Herein a 1D Co(II) coordination polymer of formula [Co(η¹-L1)(η²-L1)(py)₂(H₂O)]_n (CoCP) has been synthesised using the rigid H2L1 proligand, containing a long spacer bearing two triple bonds. Single-crystal X-ray diffraction showed that Co(II) adopts a distorted octahedral geometry. The state-averaged complete active self-consistent field (SA-CASSCF) calculation showed that the ground state of CoCP is a high spin quartet with a highly multiconfigurational character of its electronic structure. Due to the large intra- and intermolecular distances between the spin carriers, the magnetic interactions are negligible and the zero-field splitting (ZFS) effects of cobalt(II) ions are predominant. This behavior was confirmed by direct current (DC) magnetic measurements and theoretical calculations using the broken-symmetry approach. Quantum chemical calculations indicate that CoCP has a negative axial component possessing mixed tri-axial anisotropy. The DC magnetic susceptibility data were fitted with a Griffith-Figgis Hamiltonian and the obtained parameters are in good agreement with those simulated by the ab initio calculation. Alternating current (AC) magnetic measurements showed a field induced slow magnetic relaxation in CoCP, which is attributed to the hyperfine interaction effects.

Field-induced single-ion magnet based on a quasi-octahedral Co(II) complex with mixed sulfur-oxygen coordination environment

Synthesis and characterization of structure and magnetic properties of the quasi-octahedral complex (pipH₂)[Co(TDA)₂] 2H₂O (I), (pipH₂²⁺ = piperazine dication, TDA^2- = thiodiacetic anion) are described. X-ray diffraction studies reveal the first coordination sphere of the Co(II) ion, consisting of two chelating tridentate TDA ligands with a mixed sulfur-oxygen strongly elongated octahedral coordination environment. SQUID magnetometry, frequency-domain Fourier-transform (FD-FT) THz-EPR spectroscopy, and high-level ab initio SA-CASSCF/NEVPT2 quantum chemical calculations reveal a strong "easy-plane" type magnetic anisotropy (D ≈ +54 cm^-1) of complex I. The complex shows field-induced slow relaxation of magnetization at an applied DC field of 1000 Oe.

Building-up host-guest helicate motifs and chains: a magneto-structural study of new field-induced cobalt-based single-ion magnets

In this work, we present the synthetic pathway, a refined structural description, complete solid-state characterization and the magnetic properties of four new cobalt(ii) compounds of formulas [Co(H₂O)₆][Co₂(H₂mpba)₃]·2H₂O·0.5dmso (1), [Co(H₂O)₆][Co₂(H₂mpba)₃]·3H₂O·0.5dpss (2), [Co₂(H₂mpba)₂(H₂O)₄]_n·4nH₂O (3), and [Co₂(H₂mpba)₂(CH₃OH)₂(H₂O)₂]_n·0.5nH₂O·2ndpss (4) [dpss = 2,2'-dipyridyldisulfide and H₄mpba = 1,3-phenylenebis(oxamic) acid], where 2 and 4 were obtained from [Co(dpss)Cl₂] (Pre-I) as the source of cobalt(ii). All four compounds are air-stable and were prepared under ambient conditions. 1 and 2 were obtained from a slow diffusion method [cobalt(ii) : H₂mpba^2- molar ratio used 1 : 1] and their structures are made up of [Co₂(H₂mpba)₃]^2- anionic helicate units and [Co(H₂O)₆]²⁺ cations, exhibiting supramolecular three-dimensional structures. Interestingly, a supramolecular honeycomb network between the helicate units interacting with each other through R₂²(10) type hydrogen bonds occurs in 2 hosting one co-crystallized dpss molecule. On the other hand, for the first time, linear (3) and zigzag (4) cobalt(ii) chains were isolated by slow evaporation of stirred solutions of mixed solvents with cobalt(ii) : H₂mpba^2- in 1 : 2 molar ratio at room temperature. Magnetic measurements of Pre-I revealed a quasi magnetically isolated S = 3/2 spin state with a significant second-order spin-orbit contribution as expected for tetrahedrally coordinated cobalt(ii) ions. The analysis of the variable temperature static (dc) magnetic susceptibility data through first- (1 and 3) and second-order spin-orbit coupling models (2 and 4) reveals the presence of magnetically non-interacting high-spin cobalt(ii) ions with easy-axis (1 and 4)/easy-plane magnetic anisotropies (2 and 4) with low rhombic distortions. Dynamic (ac) magnetic measurements for Pre-I and 1-4 below 8.0 K show that they are examples of field-induced Single-Ion Magnets (SIMs).

Magnetism in a helicate complexes arising with the tetradentate ligand

The synthesis of [M(dimphen)(NCS)₂] (1; M = Fe^II), (2; M = Co^II), (3; M = Mn^II) and [Fe(dimphen)(NCSe)₂] (4), where dimphen = [1,2-bis(9-methyl-1,10-phenanthrolin-2-yl)ethane], are reported. The crystal packing structures of 1-3, show intermolecular π-π stacking and NCSSCN interactions. The complex 1 shows ferromagnetic interaction, and the complex 2 displays single-molecular magnet behaviour.

Switching of easy-axis to easy-plane anisotropy in cobalt(ii) complexes

In situ microcalorimetry monitored assembly and coligand induced switching of the magnetic anisotropy sign have been observed in a β-diketonate-Co(ii) system.

X-ray Structure and Magnetic Properties of Heterobimetallic Chains Based on the Use of an Octacyanidodicobalt(III) Complex as Metalloligand

The assembly of [Co2III(μ-2,5-dpp)(CN)8]2− anions and [MII(CH3OH)2(DMSO)2]2+ cations resulted into the formation of two heterobimetallic 1D coordination polymers of formula [MII(CH3OH)2(DMSO)2(μ-NC)2Co2III(μ-2,5-dpp)(CN)6]n·4nCH3OH [M = CoII (1)/FeII (2) and 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine. The [Co2III(μ-2,5-dpp)(CN)8]2− metalloligand coordinates the paramagnetic [MII(CH3OH)2(DMSO)2]2+ complex cations, in a bis-monodentate fashion, to give rise to neutral heterobimetallic chains. Cryomagnetic dc (1.9–300 K) and ac (2.0–13 K) magnetic measurements for 1 and 2 show the presence of Co(II)HS (1) and Fe(II)HS (2) ions (HS – high-spin), respectively, with D values of +53.7(5) (1) and −5.1(3) cm−1 (2) and slow magnetic relaxation for 1, this compound being a new example of SIM with transversal magnetic anisotropy. Low-temperature Q-band EPR study of 1 confirms that D value is positive, which reveals the occurrence of a strong asymmetry in the g-tensors and allows a rough estimation of the E/D ratio, whereas 2 is EPR silent. Theoretical calculations by CASSCF/NEVPT2 on 1 and 2 support the results from magnetometry and EPR. The analysis of the ac magnetic measurements of 1 shows that the relaxation of M takes place in the ground state under external magnetic dc fields through dominant Raman and direct spin-phonon processes.

Investigating Complex Magnetic Anisotropy in a Co(II) Molecular Compound: A Charge Density and Correlated Ab Initio Electronic Structure Study

Understanding magnetic anisotropy and specifically how to tailor it is crucial in the search for high-temperature single-ion magnets. Herein, we investigate the magnetic anisotropy in a six-coordinated cobalt(II) compound that has a complex geometry and distinct triaxial magnetic anisotropy from the perspective of the electronic structure, using electronic spectra, ab initio calculations, and an experimental charge density, of which the latter two provides insight into the d-orbital splitting. The analysis showed that the d-orbital splitting satisfactorily predicted the complex triaxial magnetic anisotropy exhibited by the compound. Furthermore, a novel method to directly compare the ab initio results and the d-orbital populations obtained from the experimental charge density was developed, while a topological analysis of the density provided insights into the metal-ligand bonding. This work thus further establishes the validity of using d-orbitals for predicting magnetic anisotropy in transition metal compounds while also pointing out the need for a more frequent usage of the term triaxial anisotropy in the field of single-molecule magnetism.

Tuning Magnetic Anisotropy in a Class of Co(II) Bis(hexafluoroacetylacetonate) Complexes

Tuning the magnetic anisotropy of metal ions remains highly interesting in the design of improved single-molecule magnets (SMMs). We herein report synthetic, structural, magnetic, and computational studies of four mononuclear Co^II complexes, namely [Co(hfac)₂ (MeCN)₂ ] (1), [Co(hfac)₂ (Spy)₂ ] (2), [Co(hfac)₂ (MBIm)₂ ] (3), and [Co(hfac)₂ (DMF)₂ ] (4) (MeCN=acetonitrile, hfac=hexafluoroacetylacetone, Spy=4-styrylpyridine, MbIm=5,6-dimethylbenzimidazole, DMF=N,N-dimethylformamide), with distorted octahedral geometry constructed from hexafluoroacetylacetone (hfac) and various axial ligands. By a building block approach, complexes 2-4 were synthesized by recrystallization of the starting material of 1 from various ligands containing solution. Magnetic and theoretical studies reveal that 1-4 possess large positive D values and relative small E parameters, indicating easy-plane magnetic anisotropy with significant rhombic anisotropy in 1-4. Dynamic alternative current (ac) magnetic susceptibility measurements indicate that these complexes exhibit slow magnetic relaxation under external fields, suggesting field-induced single-ion magnets (SIMs) of 1-4. These results provide a promising platform to achieve fine tuning of magnetic anisotropy through varying the axial ligands based on Co(II) bis(hexafluoroacetylacetonate) complexes.

Influence of ligand field on magnetic anisotropy in a family of pentacoordinate CoII complexes

A family of mononuclear penta-coordinated CoII complexes, [Co(L)Cl2]·CH3OH (1), [Co(L)Br2] (2) and [Co(L)(NCS)2] (3) (where L is 1-mesityl-N,N-bis(pyridin-2-ylmethyl)methanamine) were synthesized and characterized. In these complexes, the neutral non-planar ligand, L, binds to three coordination sites around the metal center while two others are bound by anionic halide/pseudo halide ligands. The coordination geometry of the complexes is dictated by the coordinated anionic ligands. Thus, the coordination geometry around the metal ion is distorted trigonal bipyramidal for complexes 1 and 3, while it is distorted square pyramidal for complex 2. Ab initio CASSCF/NEVPT2 calculations on the complexes reveal the presence of an easy plane magnetic anisotropy with the D and E/D values being, 13.3 and 0.14 cm-1 for 1; 36.1 and 0.24 cm-1 for 2 and ±8.6 and 0.32 cm-1 for 3. These values are in good agreement with the values that were extracted from the experimental DC data. AC magnetic measurements reveal the presence of a field-induced slow relaxation of magnetization. However, clear maxima in the out-of-phase susceptibility curves were not observed for 1 and 3. For complex 2, peak maxima were observed when the measurements were carried out under an applied field of 1400 Oe which allowed an analysis of the dynamics of the slow relaxation of magnetization. This revealed that the relaxation is mainly controlled by the Raman and direct processes with the values of the parameters found to be: B = 0.77(15) s-1 K-6.35, n = 6.35(12) and A = 3.41(4) × 10-10 s-1 Oe-4 K-1 and m = 4 (fixed). The ab initio calculation which showed the multifunctional nature of the electronic states of the complexes justifies the absence of zero-field SIM behaviour of the complexes. The magnitude and sign of the D and E values and their relationship with the covalency of the metal-ligand bonds was analysed by the CASSCF/NEVPT2 as well as AILFT calculations.

Tuning magnetic anisotropy by the π-bonding features of the axial ligands and the electronic effects of gold(i) atoms in 2D {Co(L)2[Au(CN)2]2}n metal–organic frameworks with field-induced single-ion magnet behaviour

Au^I atoms play an important role in determining the anisotropy of Co^II nodes in 2D Au^I–Co^II field-induced SIMs.

A Series of Field-Induced Single-Ion Magnets Based on the Seven-Coordinate Co(II) Complexes with the Pentadentate (N3O2) H2dapsc Ligand

A series of five new mononuclear pentagonal bipyramidal Co(II) complexes with the equatorial 2,6-diacetylpyridine bis(semicarbazone) ligand (H2dapsc) and various axial pseudohalide ligands (SCN, SeCN, N(CN)2, C(CN)3, and N3) was prepared and structurally characterizated: [Co(H2dapsc)(SCN)2]∙0.5C2H5OH (1), [Co(H2dapsc)(SeCN)2]∙0.5C2H5OH (2), [Co(H2dapsc)(N(CN)2)2]∙2H2O (3), [Co(H2dapsc)(C(CN)3)(H2O)](NO3)∙1.16H2O (4), and {[Co(H2dapsc)(H2O)(N3)][Co(H2dapsc)(N3)2]}N3∙4H2O (5). The combined analyses of the experimental DС and AC magnetic data of the complexes (1–5) and two other earlier described those of this family [Co(H2dapsc)(H2O)2)](NO3)2∙2H2O (6) and [Co(H2dapsc)(Cl)(H2O)]Cl∙2H2O (7), their theoretical description and the ab initio CASSCF/NEVPT2 calculations reveal large easy-plane magnetic anisotropies for all complexes (D = + 35 − 40 cm‒1). All complexes under consideration demonstrate slow magnetic relaxation with dominant Raman and direct spin–phonon processes at static magnetic field and so they belong to the class of field-induced single-ion magnets (SIMs).

Slow Magnetic Relaxation in Dinuclear CoIIYIII Complexes

Four new dinuclear complexes, [Co(μ-L)(μ-CCl₃COO)Y(NO₃)₂]·2CHCl₃·CH₃CN·2H₂O (1), [Co(μ-L)(μ-CH₃COO)Y(NO₃)₂]·CH₃CN (2), [Co(μ-L)(μ-PhCOO)Y(NO₃)₂]·3CH₃CN·2H₂O (3), and [Co(μ-L)(μ-^tBuCOO)Y(NO₃)₂]·CHCl₃·2H₂O (4), having a Co^IIY^III core, have been synthesized by employing a ferrocene based compartmental ligand which was synthesized by the reaction of diacetyl ferrocene with hydrazine hydrate followed by a condensation reaction with o-vanillin. A general synthetic protocol was employed to synthesize complexes 1-4, where the metallic core was kept the same with changing the bridging carboxylate groups. In all the complexes, the main structural motif is kept similar by only slightly varying the substitution on the bridging acetate groups. This variation has resulted in a small but subtle influence on the magnetic relaxation of all these four compounds. Ab initio CASSCF/NEVPT2 calculations were carried out to assess the effect of the different substitutions of the bridging ligands on the magnetic anisotropy parameters and on orbital arrangements. Ab initio calculations yield a very large positive D value, which is consistent with the geometry around the Co^II ion and easy plane anisotropy (g_xx, g_yy > g_zz), with the order of the calculated D in the range of 72.4 to 91.7 cm^-1 being estimated in this set of complexes. To ascertain the sign of zero-field splitting in these complexes, EPR spectra were recorded, which support the sign of D values estimated from ab initio calculations.

1D coordination polymer (OPD)2CoIISO4 showing SMM behaviour and multiple relaxation modes

A novel one-dimensional Co^II coordination polymer (OPD)₂Co^IISO₄ was formed from alternating tetrahedral sulphate anions, Co centers and molecules of 1,2-phenylenediamine (OPD). The thermal stability of the structure was confirmed up to ∼230 °C using thermogravimetry and non-ambient powder X-ray diffraction in air. The distorted pseudo-octahedral coordination sphere of Co^II ions promotes strong magnetic anisotropy. Therefore (OPD)₂Co^IISO₄ was subjected to thorough characterization with ab initio and DFT calculations along with dc magnetic measurements both of which point to strong easy-axis anisotropy (D/k_B≈-87 K, E/k_B≈ 23 K). The analysis of ac susceptibility revealed field assisted magnetic relaxation in two field regimes: a low field one with one relaxation time and a high field one where three relaxation times were distinguished. The main role in relaxations of the fastest process (τ₁) was attributed to the direct and Raman processes.

Slow Magnetic Relaxation Triggered by a Structural Phase Transition in Long-Chain-Alkylated Cobalt(II) Single-Ion Magnets

The behavior of single-ion magnets (SIMs) that reflects large distortions of their coordination environments caused by the packing of long alkyl chains for two Co(II) complexes of the type [Co(C _n-terpy)₂](BF₄)₂ (C _n-terpy = 4'-alkoxy-2,2':6',2″-terpyridine; n = 10 (1), 16 (2)) is reported. 1·2MeOH, which features a highly distorted octahedral high-spin Co(II) center, exhibits field-induced slow magnetic relaxation under an applied dc field of 1000 Oe. Further detailed analysis of the relaxation process indicated the prevalence of the Raman process at low temperature. Surprisingly, 2 shows a reverse spin transition (rST) and also exhibits remarkable field-induced SIM behavior, revealing the presence of magnetic anisotropy for this high-spin Co(II) species that is triggered by a structural phase transition. We present here the first examples of the coexistence of field-induced slow magnetic relaxation and rST associated with structural phase transitions involving long-alkyl-chain conformational changes from gauche to anti. These results indicate the prospect of inducing SIM properties in other distorted high-spin Co(II) species bearing long alkyl chains.

Field-induced slow relaxation of magnetization in the S = 3/2 octahedral complexes trans-[Co{(OPPh2)(EPPh2)N}2(dmf)2], E = S, Se: effects of Co–Se vs. Co–S coordination

Magnetometry studies on octahedral trans-[Co{(OPPh₂)(EPPh₂)N}₂(dmf)₂], E = S, Se, complexes.

Dinuclear CoIIYIIIvs. tetranuclear CoII2YIII2 complexes: the effect of increasing molecular size on magnetic anisotropy and relaxation dynamics

The lower distortion of the Co^II ions in the new tetranuclear CoII2YIII2 complex leads to a larger magnetic anisotropy than in its Co^IIY^III counterparts, whereas its larger size and flexibility seem to promote a faster relaxation dynamic.

Field-induced single-ion magnet behaviour of a hexacoordinated Co(ii) complex with easy-axis-type magnetic anisotropy

This study presents the novel hexacoordinated Co(ii) mononuclear complex with SIM behavior.

ESR analyses of picket fence MnII and 6th ligand coordinated FeIII porphyrins (S = 5/2) and a CoII(hfac) complex (S = 3/2) with sizable ZFS parameters revisited: a full spin Hamiltonian approach and quantum chemical calculations

The conventional X-band ESR spectra are fully reanalyzed by a full spin Hamiltonian approach.

Magnetic relaxation in cobalt(ii)-based single-ion magnets influenced by distortion of the pseudotetrahedral [N2O2] coordination environment

Cobalt(ii) complexes with different dihedral angles between the bidentate ligands show a significant variation in their magnetic relaxation behavior.

Impact of nuclearity and topology on the single molecule magnet behaviour of hexaazatrinaphtylene-based cobalt complexes

A hexaazatrinaphtylene-based transition metal complex that exhibits single molecule magnet behaviour is reported herein. This study reveals the influence of both nuclearity and topology on the magnetic properties of hexaazatrinaphtylene-based complexes.

Magnetic anisotropy and relaxation behavior of six-coordinate tris(pivalato)-Co(ii) and -Ni(ii) complexes

Magnetic measurements, HFEPR and theoretical calculations have been used to study the magnetic anisotropy of the six-coordinate field-induced single ion magnet (NBu₄)[Co(piv)₃] and its Ni analogue.