Themed collection Spotlight Collection: Lanthanide and transition metal complexes as molecular magnets

Guest editor Vadapalli Chandrasekhar introduces the spotlight collection “Lanthanide and transition metal complexes as molecular magnets”.

The design of dissymmetric organic ligands has been exploited to produce heterometallic dinuclear and trinuclear lanthanide-based coordination compounds with the requirements to act as logical quantum gates for spin-based quantum computing.

Multifunctional molecular materials exhibiting electrical conductivity and single-molecule magnet (SMM) behaviour are particularly attractive for electronic devices and related applications owing to the interaction between electronic conduction and magnetization of unimolecular units.

A series of rare six-coordinated dinuclear Ln(III) complexes were characterized using a bulky amide ligand. Dy(III) analogue shows slow relaxation of magnetization in the absence of an external magnetic field. This has been rationalized by ab initio calculations.

CASSCF-SO calculations in OpenMolcas are used to determine Slater-Condon and SOC parameters for 3dⁿ, 4dⁿ, 5dⁿ and 4fⁿ ions. We quantify the error of minimal active space approaches and compare to other similar methods.

Two mononuclear complexes including the same cation [Co(imidazole)₆]²⁺ and the different symmetries C_i and D_3d showed discriminatively slow magnetic relaxation.

We present the synthesis and characterisation of two dysprosium metallocene complexes with bound weakly coordinating anions. Despite their similarity these complexes exhibit vastly different effective energy barriers to magnetic reversal.

Bis(pyrazolato)-bridged macrocycles are shown to serve as scaffolds for Dy₂ single molecule magnets with control over the relative orientation of anisotropy axes.

The halogeno-cyanido Pt^IV complex was used as a metalloligand in emissive {Dy^III₂Pt^IV₃} single-molecule magnets tuned by the solvent-dependent coordination geometry and alignment of Me₃PO ligands.

Three {Co^II(^Rbik)₂} single-ion magnets (SIMs) based on the ^Mebik ligand [^Mebik = bis(1-methylimidazol-2-yl)ketone] and one mixed-valence {Co^III₂Co^II}_n chain of Co^II SIMs connected by diamagnetic {Co^III₂(μ-2,5-dpp)(CN)₈} spacers are discussed.

3d–4f metal–metal bonds are utilised to enhance exchange coupling to the order of several hundred wavenumbers.

Two polyoxometalate-based frameworks containing holmium and terbium are synthesized. Their single-molecule magnet (SMM) properties are investigated, where weak field-induced SMM behaviour is observed at low temperatures in dynamic magnetic studies.

A rare isostructural series of cyanido-bridged {Fe^IIILn^III}₂ square-shaped heterobimetallic complexes were obtained, in which Tb^III, Dy^III and Er^III derivatives show slow magnetization relaxation under zero and non-zero static fields.

3d–4f complexes were prepared and their X-ray analyses revealed changes in the coordination number upon changing the lanthanide (Gd → Er). The V^IV–Ln^III magnetic exchange was fit from magnetic data and calculated by DFT and CASSCF theoretical models.

The length of the alkyl chain substituents employed in complexes [Fe(H₂Bpz₂)₂(C_n-bipy)] can have a large impact on the transition temperature and solid state spin crossover profile.

Single molecule magnetic features of new {Ru^III₂Dy^III₂} “butterfly” clusters are compared, by experiment and theory, to those of 3d/4f analogues.

The insertion of Na⁺ ions into the structure of Ln^III₂Cu^II₂ hydroxo-trimethylacetate complexes leads to a change in the butterfly-like metal core geometry giving rise to a significant change in their slow magnetic relaxation.

Isotopic enrichment and magnetic dilution influenced the magnetic performance of a 3d4f heterobimetallic single-molecule magnet in both zero and applied magnetic field.

An in silico proof of concept showed that detectable changes in magnetic anisotropies can be achieved by applying pressure on molecular magnetic systems containing lanthanides.

Ligand oxidation of single-molecule magnets enhances magnetic relaxations via higher energy levels.

The iron(II)-based extended metal atom chains [Fe₄(tpda)₃X₂] (X = Cl, Br) have a weakly magnetic ground state but display SMM properties, which are detectable even in zero DC field when X = Br.

The diverse relaxation dynamics of a series of Dy^III-based SIMs resulting from the coordinated molecules and counter anions were elucidated by structural analysis, magnetic investigations and ab initio calculations.

A hexaaqua Co^II complex within the anionic metal oxide cluster of decavanadates reveals easy-axis anisotropy and field induced SIM behaviour with a high energy barrier for the spin reversal process.

Two penta-coordinate [Co(Lⁿ)(NCS)]ClO₄ with substituted pyridyl based bispyrazolyl ligands have been structurally characterized. The complexes show an easy-axis magnetic anisotropy, large rhombicity and slow relaxation of magnetization.

Here we report the radii-dependent self-assembly of chiral lanthanide complexes and the single-molecule magnet behavior of the Dy₅ complexes.

A novel heteroheptanuclear metal string complex was synthesized by using nickel and ruthenium metal ions to explore the electronic structure and magnetic property.

Tuning the magnetic dynamics of single-molecule magnets (SMMs) is a crucial challenge for chemists.

As a difunctional material, an azido-Co(II) coordination polymer with a high-nitrogen content exhibits both molecule-based magnetic behaviour and high-energy performance with superior thermostability and insensitivity.

Five Ln-MOFs were obtained: the Dy-MOF shows slow magnetic relaxation, and the Eu-MOF and Tb-MOF show selective and sensitive sensing towards Fe³⁺ ions and ketones in a water system.

Herein, we report the synthesis, structure, and magnetism of five tetranuclear Ln^III complexes encapsulated by 5-(4-pyridinecarboxaldehyde)amino-8-hydroxylquinoline and β-diketonate coligand.