Optical Phenomena in Molecule-Based Magnetic Materials

Since the last century, we have witnessed the development of molecular magnetism which deals with magnetic materials based on molecular species, i.e., organic radicals and metal complexes. Among them, the broadest attention was devoted to molecule-based ferro-/ferrimagnets, spin transition materials, including those exploring electron transfer, molecular nanomagnets, such as single-molecule magnets (SMMs), molecular qubits, and stimuli-responsive magnetic materials. Their physical properties open the application horizons in sensors, data storage, spintronics, and quantum computation. It was found that various optical phenomena, such as thermochromism, photoswitching of magnetic and optical characteristics, luminescence, nonlinear optical and chiroptical effects, as well as optical responsivity to external stimuli, can be implemented into molecule-based magnetic materials. Moreover, the fruitful interactions of these optical effects with magnetism in molecule-based materials can provide new physical cross-effects and multifunctionality, enriching the applications in optical, electronic, and magnetic devices. This Review aims to show the scope of optical phenomena generated in molecule-based magnetic materials, including the recent advances in such areas as high-temperature photomagnetism, optical thermometry utilizing SMMs, optical addressability of molecular qubits, magneto-chiral dichroism, and opto-magneto-electric multifunctionality. These findings are discussed in the context of the types of optical phenomena accessible for various classes of molecule-based magnetic materials.

Lanthanide Phosphonates and Phosphates in Molecular Magnetism

Phosphonate and phosphate ligands have historically received less attention when compared to the widely prevalent carboxylate ligand system. Phosphonates possess multiple donating sites, often leading to the formation of larger aggregates with limited solubility. Conversely, the P-O bond within phosphates is highly susceptible to hydrolysis, resulting in the precipitation of insoluble compounds, particularly when interacting with lanthanide metal ions. However, over the past few decades, various synthetic approaches have emerged for the preparation and characterization of lanthanide complexes involving both phosphonate and phosphate ligands. Consequently, researchers have delved into exploring the magnetic properties of these complexes, such as their potential as single molecule magnets (SMMs) and their ability to exhibit a magnetocaloric effect (MCE). This review will encompass an examination of the crystal structures and magnetic characteristics of lanthanide complexes featuring phosphonate and phosphate ligands.

Single molecule magnet features in luminescent lanthanide coordination polymers with heptacoordinate Dy/Yb(III) ions as nodes

Two sets of 1D/2D lanthanide coordination polymers with formulas of Ln(oqa)3·2H2O [Hoqa = 2-(4-oxoquinolin-1(4H)-yl) acetic acid, Ln = Dy (1), Yb (2)] and Ln(oaa)2(HCOO)(H2O) [Hoaa = 2-(9-oxoacridin-10(9H)-yl) acetic acid, Ln = Dy (3), Yb (4)] have been synthesized and their physical properties were investigated. All four complexes are constructed from seven-coordinate lanthanide ions and corresponding organic linkers. The lanthanide ions in 1 and 2 adopt a pentagonal bipyramid coordination geometry, whereas the coordination geometry of lanthanide ions in 3 and 4 can be described as a capped octahedron. Slow magnetic relaxation behaviors were observed in these four products at a zero/non-zero static magnetic field. Complexes 1, 2 and 4 exhibit the characteristic emission of Ln(III) ions, whereas complex 3 shows ligand-based emission. Bright yellow light emission was also observed when a voltage was applied, demonstrating the potential of 1 for application in light-emitting diodes (LEDs). Compounds 3 and 4 are the first examples of lanthanide complexes based on Hoaa ligands.

Circularly polarized luminescence in the one-dimensional assembly of binaphtyl-based Yb(iii) single-molecule magnets

Lanthanide ions have attracted great interest owing to their optical and magnetic properties. Single-molecule magnet (SMM) behavior has been a fascinating science for thirty years. Moreover, chiral lanthanide complexes allow the observation of remarkable circularly polarized luminescence (CPL). However, the combination of both SMM and CPL behaviors in a single molecular system is very rare and deserves attention in the design of multifunctional materials. Four chiral one-dimensional coordination compounds involving 1,1'-Bi-2-naphtol (BINOL)-derived bisphosphate ligands and the Yb(iii) centre were synthesized and characterized by powder and single-crystal X-ray diffraction. All the Yb(iii)-based polymers displayed field-induced SMM behavior with magnetic relaxation occurring by applying Raman processes and near infrared CPL in the solid state.

Effect of the Transition Metal Ions on the Single-Molecule Magnet Properties in a Family of Air-Stable 3d-4f Ion-Pair Compounds with Pentagonal Bipyramidal Ln(III) Ions

Single-molecule magnets (SMMs) are expected to be promising candidates for the applications of high-density information storage materials and quantum information processing. Lanthanide SMMs have attracted considerable interest in recent years due to their excellent performance. It has always been interesting but not straightforward to study the relaxation and blocking mechanisms by embedding 3d ions into 4f SMMs. Here we report a family of air-stable 3d-4f ion-pair compounds, YFe (1), DyCr (2), DyFe (3), DyCo (4), and Dy_0.04Y_0.96Fe (5), composed of pentagonal bipyramidal (D_5h) Ln^III cations and transition metallocyanate anions. The ion-pair nature makes the dipole-dipole interactions almost the only component of the magnetic interactions that can be clarified and analytically resolved under proper approximation. Therefore, this family provides an intuitive opportunity to investigate the effects of 3d-4f and 4f-4f magnetic interactions on the behavior of site-resolved 4f SMMs. Dynamic magnetic measurements of 1 under a 4 kOe external field reveal slow magnetic relaxation originating from the isolated [Fe^III]_LS (S = ¹/₂) ions. Under zero dc field, compounds 2-5 show similar magnetic relaxation processes coming from the separated pentagonal bipyramidal (D_5h) Dy^III ions with high Orbach barriers of 592(5), 596(4), 595(3), and 606(4) K, respectively. Comparatively, both compounds 3 and 5 exhibit two distinct relaxation processes, respectively from the [Fe^III]_LS and Dy^III [U_eff = 596(4) K for 3 and 610(7) K for 5] ions, under a 4 kOe dc field. The dipolar interactions between the neighboring TM^III (TM = transition metal, Cr^III or [Fe^III]_LS) and Dy^III ions were revealed to have little effect on the thermal relaxation in compounds 2, 3, and 5, or the coexistence of the two separate relaxation processes in compounds 3 and 5 under a 4 kOe dc field, but they significantly affect the quantum tunneling of magnetization and the magnetic hysteresis behavior of 2 and 3 at low temperatures compared to those of 4.

Magnetic anisotropies of Ho(III) and Dy(III) single-molecule magnets experimentally determined via polarized neutron diffraction

We present the magnetic anisotropy of two isostructural pentagonal-bipyramidal complexes, [Ln(H₂O)₅(HMPA)₂]I₃·2HMPA (HMPA = hexamethylphosphoramide, Ln = Dy, Ho). Using ac magnetic susceptibility measurements, we find magnetic relaxation barriers of 600 K and 270 K for the Dy- and Ho-compounds, respectively. This difference is supported by polarized neutron diffraction (PND) measured at 5 K and 1 T which provides the first experimental evidence that the transverse elements in the magnetic anisotropy of the Ho-analogue are significant, whereas the Dy-analogue has a near-axial magnetic anisotropy with vanishing transverse contributions. The coordination geometries of the two complexes are highly similar, and we attribute the loss of strong magnetic axiality as expressed in the atomic susceptibility tensors from PND, as well as the smaller relaxation barrier in the Ho-complex compared to the Dy-complex, to the less favorable interaction of the pentagonal bipyramidal crystal field with the characteristics of the Ho(III) 4f-charge distribution.

Enhancing the Magnetic Anisotropy in Low-Symmetry Dy-Based Complexes by Tuning the Bond Length

One mononuclear complex [Dy(Htpy)(NO₃)₂(acac)] (1) and a tpy^--extended 1D chain {[Dy(CH₃OH)(NO₃)₂(tpy)]·CH₃OH}_n (2) (Htpy = 4'-(4-hydroxyphenyl)-2,2':6',2''-terpyridine, Hacac = acetylacetone) were successfully designed to investigate the effect of bond length tuning around the Dy^III cation on the magnetic dynamics of single-molecule magnets (SMMs). Interestingly, two magnetic entities possess the same local coordination sphere (N₃O₆-donor) as well as the configuration (Muffin, C_s) of dysprosium centers. Only a slight difference in structure results from purposefully substituting the acetylacetone ligand in 1 with hydroxyl oxygen from tpy^- linkage and one methanol molecule in 2. However, the remarkable differences in dynamics behavior were clearly found between them. Compound 1 possesses a thermal-activated effective energy barrier (U_eff/k_B) of 22.7 K under a 0 kOe direct current (dc) field and negligible hysteresis loop at 2.0 K, while complex 2 shows high-performance SMM behavior with the largest energy barrier of 354.36 K among the reported nine-coordinated Dy^III-based systems and the magnetic hysteresis up to 4.0 K at a sweep rate of 200 Oe s^-1. These experimental results combined with the previous reported data reveal that the shortest bond and the bond length difference around the Dy^III center synergistically determine the dynamics of SMMs. The uniaxial anisotropy increases with the decrease of the shortest bond and the increase of the bond length difference, which is confirmed by the theoretical calculations.

Homochiral Dysprosium Phosphonate Nanowires: Morphology Control and Magnetic Dynamics

Controllable synthesis of uniformly distributed nanowires of coordination polymers with inherent physical functions is highly desirable but challenging. In particular, the combination of chirality and magnetism into nanowires has potential applications in multifunctional materials and spintronic devices. Herein, we report four pairs of enantiopure coordination polymers with formulae S-, R-Dy(cyampH)₃  ⋅ CH₃ COOH ⋅ 2H₂ O (S-1, R-1), S-, R-Dy(cyampH)₃  ⋅ 3H₂ O (S-2, R-2), S-, R-Dy(cyampH)₂ (C₂ H₅ COO) ⋅ 3H₂ O (S-3, R-3) and S-, R-Dy(cyampH)₃  ⋅ 0.5C₂ H₅ COOH ⋅ 2H₂ O (S-4, R-4) [cyampH₂ =S-, R-(1-cyclohexylethyl)aminomethylphosphonic acids], which were obtained depending on the pH of the reaction mixtures and the specific carboxylic acid used as pH regulator. Interestingly, compounds 3 were obtained as superlong nanowires, showing 1D neutral chain structure which contains both phosphonate and propionate anion ligands. While compounds 1, 2 and 4 appeared as block-like crystals, superhelices and nanorods, respectively, and exhibited similar neutral chain structures containing only phosphonate ligand. Slow magnetization relaxation characteristic of single-molecule magnet (SMM) behavior was observed for compounds S-1 and S-3. Theoretical calculations were performed to rationalize the magneto-structural relationships.

Chiral or Luminescent Lanthanide Single-Molecule Magnets Involving Bridging Redox Active Triad Ligand

The reactions between the bis(1,10-phenantro[5,6-b])tetrathiafulvalene triad (L) and the metallo-precursors Yb(hfac)3(H2O)2 (hfac− = 1,1,1,5,5,5-hexafluoroacetylacetonato anion) and Dy(facam)3 (facam− = 3-trifluoro-acetyl-(+)-camphorato anion) lead to the formation of two dinuclear complexes of formula [Yb2(hfac)6(L)]·2(C7H16) ((1)·2(C7H16)) and [Dy2((+)facam)6(L)]·2(C6H14) ((2)·2(C6H14)). The X-ray structures reveal that the L triad bridges two terminal Yb(hfac)3 or Dy(facam)3 units. (1)·2(C7H16) behaved as a near infrared YbIII centered emitter and a field-induced Single-Molecule Magnet (SMM) while (2)·2(C6H14) displayed SMM behavior in both zero- and in-dc field. The magnetization mainly relaxes through a Raman process for both complexes under an optimal applied magnetic field.

The comparative studies on the magnetic relaxation behaviour of the axially-elongated pentagonal-bipyramidal dysprosium and erbium ions in similar one-dimensional chain structures

A family of cyano-bridged 3d-4f 1D chain compounds, {RE[TM(CN)6(2-PNO)5]}·(H2O)4 {RE = YIII, TM = [FeIII]LS (1); RE = DyIII, TM = CoIII (3); RE = ErIII, TM = [FeIII]LS (4), CoIII (5); 2-PNO = 2-picoline-N-oxide} and {RE[TM(CN)6(2-PNO)5]} {RE = DyIII, TM = [FeIII]LS (2)}, were synthesized and characterized. Single-crystal X-ray diffraction studies reveal that compounds 1 and 3-5 are isostructural, while compound 2 has a similar 1D chain structure with a different chain to chain arrangement. An axially-elongated pentagonal bipyramidal (D5h) coordination geometry is formed with five 2-PNO ligands in the equatorial plane and two [TM(CN)6]3- on the apical sites around the rare earth ions in these compounds. A comparison of the magnetic relaxation behaviour in detail reveals that it is more favorable for the Er (4 and 5) than the Dy analogues (2 and 3) to exhibit SIM properties in this axially-elongated D5h coordination environment. Under zero dc field, ac susceptibility measurements show that the Dy analogues have no magnetic relaxation behaviour, while the Er analogues exhibit frequency dependence despite the strong QTM effect. Under a 1 kOe dc field, the Er analogues generally show 1-2 orders of magnitude longer relaxation time at each selected temperature and a higher relaxation energy barrier than the Dy analogues. And the RECo compounds (3 and 5) show a more suppressed QTM effect than the corresponding REFe (2 and 4) compounds, which may be ascribed to the elimination of the fluctuation field from the neighbouring [FeIII]LS ions. The ab initio calculations indicate the misplacement between the orientation of the main magnetic axis and the structural axis in the Dy analogues, and the relative consistency in the Er analogues, which should be the source of the Er analogues showing better SIM properties than the Dy analogues.

Luminescent dysprosium single-molecule magnets made from designed chiral BINOL-derived bisphosphate ligands

The nature of the aromatic system and the number of chiral centers of the BINOL derived bisphosphate ligands influence both the chiroptical properties and single-molecule magnet behavior of a series of dysprosium-based chains.

Solid-state versus solution investigation of a luminescent chiral BINOL-derived bisphosphate single-molecule magnet

The enantiopure coordination polymer [Dy(hfac)₃((S/R)-L)]_n ([(S/R)-1]n) involving a BINOL-derived bisphosphate ligand (S/R)-L is investigated both in solution and solid-state.

Ten-Coordinate Lanthanide [Ln(HL)(L)] Complexes (Ln = Dy, Ho, Er, Tb) with Pentadentate N3O2-Type Schiff-Base Ligands: Synthesis, Structure and Magnetism

A series of five neutral mononuclear lanthanide complexes [Ln(HL)(L)] (Ln = Dy3+, Ho3+ Er3+ and Tb3+) with rigid pentadentate N3O2-type Schiff base ligands, H2LH (1-Dy, 3-Ho, 4-Er and 6-Tb complexes) or H2LOCH3, (2-Dy complex) has been synthesized by reaction of two equivalents of 1,1′-(pyridine-2,6-diyl)bis(ethan-1-yl-1-ylidene))dibenzohydrazine (H2LH, [H2DAPBH]) or 1,1′-(pyridine-2,6-diyl)bis(ethan-1-yl-1-ylidene))di-4-methoxybenzohydrazine (H2LOCH3, [H2DAPMBH]) with common lanthanide salts. The terbium complex [Tb(LH)(NO3)(H2O)2](DME)2 (5-Tb) with one ligand H2LH was also obtained and characterized. Single crystal X-ray analysis shows that complexes 1–4 have the composition {[Ln3+(HL)−(L)2−] solv} and similar molecular structures. In all the compounds, the central Ln3+ ion is chelated by two interlocked pentadentate ligands resulting in the coordination number of ten. Each lanthanide ion is coordinated by six nitrogen atoms and four oxygen atoms of the two N3O2 chelating groups forming together a distorted bicapped square antiprismatic polyhedron N6O4 with two capping pyridyl N atoms in the apical positions. The ac magnetic measurements reveal field-induced single-molecule magnet (SMM) behavior of the two dysprosium complexes (with barriers of Ueff = 29 K at 800 Oe in 1-Dy and Ueff = 70 K at 300 Oe in 2-Dy) and erbium complex (Ueff = 87 K at 1500 Oe in 4-Er); complex 3-Ho with a non-Kramers Ho3+ ion is SMM-silent. Although 2-Dy differs from 1-Dy only by a distant methoxy-group in the phenyl ring of the ligand, their dynamic magnetic properties are markedly different. This feature can be due to the difference in long-range contributions (beyond the first coordination sphere) to the crystal-field (CF) potential of 4f electrons of Dy3+ ion that affects magnetic characteristics of the ground and excited CF states. Magnetic behavior and the electronic structure of Ln3+ ions of 1–4 complexes are analyzed in terms of CF calculations.

Luminescent Ir(iii)–Ln(iii) coordination polymers showing slow magnetization relaxation

Two structural types of iridium(iii)–lanthanide(iii) coordination polymers, single-chain Ir2Ln and double-chain Ir4Ln2 (Ln = Gd, Dy, Er, and Yb), have been prepared. SMM behaviour and NIR luminescence were observed for the Ir–Er and Ir–Yb systems.

Metal phosphonates incorporating metalloligands: assembly, structures and properties

This feature article summarizes the current status of metal–metalloligand phosphonates including the synthetic strategies, crystal structures and properties. Future challenges in this field are discussed.

One-dimensional lanthanide coordination polymers supported by pentadentate Schiff-base and diphenyl phosphate ligands: single molecule magnet behavior and photoluminescence

Four one-dimensional lanthanide coordination polymers constructed from Ln₂ dimers showing single molecule magnet behavior and photoluminescence are reported.

Interplay of anthracene luminescence and dysprosium magnetism by steric control of photodimerization

Systematic control of the intermolecular pair-wise [4 + 4] photocycloaddition of a series of dysprosium phosphonates through fine-tuning of two different phosphonate ligands, one with a bidentate blocker and one with an anthracene antenna, both with alkyl substituents, reveals a size dependent rate. With bulky isopropyl on the diphosphonate blocker little response to UV light is observed. In contrast, compounds with ethyl which has less steric hindrance exhibit almost complete photocycloaddition. Interestingly, the alkyl substituents attached to anthracene monophosphonate have no evident effect on the reaction rate. Although no direct relationship can be found between the substitutions and the observed differences in field-induced single molecule magnetism, remarkable changes in magnetic dynamics are observed for complexes before and after the complete photocycloaddition reactions.

Fine-tuning the type of equatorial donor atom in pentagonal bipyramidal Dy(iii) complexes to enhance single-molecule magnet properties

Upon fine-tuning an equatorial donor, the electronic effect is implemented to significantly enhance magnetic anisotropy in pentagonal bipyramidal Dy^III complexes.

High local coordination symmetry around the spin center and the alignment between magnetic and symmetric axes together play a crucial role in single-molecule magnet performance

A tetradentate 8-hydroxyquinoline-based acyl hydrazine ligand was used to construct a series of mono/di-nuclear dysprosium single-molecule magnets (SMMs) with nearly ideal pentagonal bipyramid coordination geometry (D_5h).

Terbium Oxalatophosphonate as Efficient Multiresponsive Luminescent Sensors for Chromate Anions and Tryptophan Molecules

A stable 2D terbium oxalatophosphonate with green luminescence, namely, [Tb2(H3L)(C2O4)3(H2O)4]·2H2O (1), has been hydrothermally obtained by using (4-carboxypiperidyl)-N-methylenephosphonic acid (H3L) and oxalate ligand. The luminescent investigation indicates that the emission behavior of compound 1 shows high water and pH stabilities. It can be applied as a multiresponsive luminescent probe with high selectivity, high sensitivity, recycling capability, and fast sensing of CrO4 2-, Cr2O7 2- anions and tryptophan (Trp) molecules in aqueous solution through the luminescence quenching effect. Moreover, the sensing results can be distinguished by the naked eye under the irradiation of UV light of 254 nm. In addition, the probable mechanisms for the quenching behavior are also discussed, which can be mainly attributed to the competitive absorption of excitation energy between compound 1 and the analytes.

Enriching lanthanide single-ion magnetism through symmetry and axiality

Rapidly growing modern information technology demands energy and cost efficient tools that can efficiently store and process a large amount of data. However, the miniaturization technology that was being used to boost the performance of the electronic devices, keeping up with the pace as estimated by Moore's law, is reaching its limit. To overcome these challenges, several alternative routes that can eventually mimic the modern electronics fabrication using silicon have been proposed. Single molecule magnets (SMMs), being considered as one of the potential alternatives, have gone through significant progress and the focus has shifted from the use of polynuclear clusters to mononuclear complexes in the last few years. The recent frenzy in the field of SMMs is driven by a better understanding of the effects of crystal field (CF) and molecular symmetry on the magnetic properties, especially in the case of mononuclear paramagnetic complexes, apart from other controlling factors. This has led to the advent of highly anisotropic single-ion magnets (SIMs) with magnetic blocking temperatures as high as 60 K and anisotropic energy barriers over 1800 K. This article overviews our recent research in the light of the emergence of the importance of CF and symmetry in 4f ion based single-ion magnets (SIMs), especially in the context of SIMs with D5h symmetry, apart from commenting on the synthetic efforts adopted to place these metal ions in unusual coordination geometries.

Slow magnetic relaxation in luminescent mononuclear dysprosium(iii) and erbium(iii) pentanitrate complexes with the same LnO10 coordination geometry

Two isostructural mononuclear Dy and Er pentanitrate complexes with an LnO₁₀ coordination geometry have been synthesized and studied by single-crystal X-ray diffraction, luminescence and magnetic measurements. Slow relaxation of the magnetization behavior is simultaneously observed in two complexes with the same coordination environment, despite the different types of the 4f-shell electron distribution. Meanwhile, both complexes exhibit the respective characteristic Ln(iii) photoluminescence.

An intense luminescent Dy(iii) single-ion magnet with the acylpyrazolonate ligand showing two slow magnetic relaxation processes

A new Dy(iii)-acylpyrazolonate complex displays both intense yellow-light emission and single-ion magnet behavior with two slow magnetic relaxation processes, acting as a potential bifunctional material.

Lanthanide oxalatophosphonates with two types of layered structures: syntheses, structures, luminescence and magnetic properties

Five novel lanthanide(iii) oxalatophosphonates with two types of 2D layered structures have been hydrothermally obtained and structurally characterized. The luminescence and magnetic properties of the title compounds have been studied.

Investigation of magneto-structural correlation based on a series of seven-coordinated β-diketone Dy(iii) single-ion magnets with C2v and C3v local symmetry

Four field-induced single-ion magnets based on seven-coordinated Dy(iii) complexes have been prepared to explore the magnetism–structure relationship.

A Chinese Pane-Like 2D Metal-Organic Framework Showing Magnetic Relaxation and Luminescence Dual-Functions

The discovery of graphene kicked off the curtain of atom-type two-dimensional (2D) materials. Layered metal-organic frameworks (MOFs) as parallel molecule-based 2D materials are more designable and more diverse, and magnetism may be induced by their metal ion nodes. However, the multifunctional 2D plane-like MOFs are very difficult to obtain. Here we describe a Chinese pane-like 2D MOF constructed from the Ln3+ cation and the nanoscale luminescent tritopic ligand tris(4'-carboxybiphenyl)-amine, responding to the slow magnetic relaxation and luminescence properties, respectively. Notably, the Dy-Dy distances separated by the tritopic ligand are up to 2 nm. Such a 2D molecular material is expected to have potential applications in optoelectronics and multimodal sensing.

Construction of lanthanide single-molecule magnets with the “magnetic motif” [Dy(MQ)4]−

[Dy₂(MQ)₄(NO₃)₃]⁺ is SMM-silent (SMM = single-molecule magnet) owing to the unfavourable magnetic interactions. Introducing an additional “magnetic motif” [Dy(MQ)₄]⁻ to diminish such interactions gave a trinuclear [Dy₃(MQ)₈(NO₃)], which behaves as an SMM.

A family of one-dimensional lanthanide complexes bridged by two distinct carboxylate ligands with the Dy analogue displaying magnetic relaxation behaviour

Utilizing two different carboxylate ligands to construct dysprosium SMMs with relatively good performance was proven to be a successful synthetic strategy.

Enantiopure phosphonic acids as chiral inducers: homochiral crystallization of cobalt coordination polymers showing field-induced slow magnetization relaxation

Homochiral crystallization of (M)- or (P)-Co(SO₄)(1,3-bbix)(H₂O)₃ (1M or 1P) from an achiral precursor is achieved in the presence of a catalytic amount of (S)- or (R)-3-phenyl-2-((phosphonomethyl)amino) propanoic acid.

Auxiliary ligand field dominated single-molecule magnets of a series of indole-derivative β-diketone mononuclear Dy(iii) complexes

A series of β-diketone dysprosium complexes exhibit SMM properties tuned by the whole ligand field in terms of the strength of the ligand field, conjugated system and coordination symmetry around Dy(iii).

Homochiral mononuclear Dy-Schiff base complexes showing field-induced double magnetic relaxation processes

Homochiral mononuclear complexes (Et₃NH)[Dy((R,R)/(S,S)-3-NO₂salcy)₂] (1R/1S), where 3-NO₂salcyH₂ is N,N′-(1,2-cyclohexanediylethylene)bis(3-nitrosalicylideneiminato), are reported, and their optical and magnetic behaviors are studied.