Nanoscale Homochiral C3-Symmetric Mixed-Valence Manganese Cluster Complexes with Both Ferromagnetic and Ferroelectric Properties

Chiral six-coordinate Dy(iii) and Tb(iii) complexes of an achiral ligand: structure, fluorescence, and magnetism

Two new chiral six-coordinate lanthanide complexes are obtained using an achiral ligand. Complex [Zn₃Dy] displays field-induced slow magnetization relaxation, while complex [Zn₃Tb] exhibits intense green photofluorescence and triboluminescence.

Anion-directed supramolecular chemistry modulating the magnetic properties of nanoscopic Mn coordination clusters: from polynuclear high-spin complexes to SMMs

We report a supramolecular approach to mixed-valent Mn coordination clusters that demonstrates how halide ions can be applied to influence the assembly of distinct tetranuclear building units to produce a number of related Mn coordination clusters with dense core structures that derive from a cuboctahedral arrangement of Mn ions. In all compounds the alignment of the Jahn-Teller axes of the Mn^III centers coincides with the positions of the stabilizing chloride ligands. Thus, the relative chloride concentrations in the reaction mixtures allow us to modify the symmetry and magnetic anisotropy of this basic core structures resulting in isotropic polynuclear high-spin complexes at high Cl^- concentrations and Single-Molecule Magnets at lower relative Cl^- concentrations.

Chiral heterobimetallic chains from a dicyanideferrite building block including a π-conjugated TTF annulated ligand

The π-conjugated tetrathiafulvalene (TTF) annulated ligand was introduced into a dicyanometallate for the first time, leading to the synthesis of the versatile redox-active dicyanideferrite building block [(n-Bu)₄N][Fe(TTFbp)(CN)₂] (H₂TTFbp = N-(2-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)-5-(picolinamido) benzo[d][1,3]dithiol-6-yl) picol inamide). The incorporation of the new precursor with chiral Mn^III Schiff-base complexes resulted in two enantiopure one-dimensional complexes, [Mn((R,R)-salphen)Fe(TTFbp)(CN)₂]_n (2-(RR)) and [Mn((S,S)-salphen)Fe(TTFbp)(CN)₂]_n (2-(SS)) (Salphen = N,N'-1,2-diphenylethylene-bis(salicylideneiminato) dianion), which were synthesized and structurally characterized. Circular dichroism (CD) and vibrational circular dichroism (VCD) spectra confirmed the enantiomeric nature of the optically active complexes, and structural analyses revealed the formation of neutral cyanide-bridged double chains in 2-(RR) and 2-(SS). Solution and solid state CV studies revealed the redox-active characteristics of the complexes. Antiferromagnetic couplings were detected between Fe^III and Mn^III centers within a chain, and a field-induced magnetic phase transition was observed (T_N = 4.8 K). The introduction of electroactivity and chirality into cyanide-bridged complexes with interesting magnetic properties leads the way towards new multifunctional materials.

Synthesis, properties and surface self-assembly of a pentanuclear cluster based on the new π-conjugated TTF-triazole ligand

The new π-extended redox-active ligand with both TTF and triazole units, 6-(4,5-bis(propylthio)-1,3-dithiol-2-ylidene)-1H-[1,3]dithiolo[4′,5′:4,5]benzo [1,2-d] [1–3]triazole, has been successfully prepared. Based on the versatile ligand and Cu(tta)₂ precursors (tta⁻ = 4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3-dione), a TTF-based pentanuclear Cu^II cluster (Cu₅(tta)₄(TTFN₃)₆) is synthesized and structurally characterized. Their absorption and electrochemical properties are investigated. Antiferromagnetic couplings are operative between metal ion centers bridged by triazoles in the complex. The self-assembled structure of the cluster complex on a highly oriented pyrolytic graphite (HOPG) surface was observed using scanning tunneling microscopy and density functional theory (DFT) calculations have been performed to provide insight into the formation mechanism. The introduction of the redox-active TTF unit into the cluster complexes with interesting magnetic properties renders them promising candidates for new multifunctional materials.

Experimental and theoretical investigations of four 3d–4f butterfly single-molecule magnets

Experimental and theoretical investigations of four 3d–4f defect-dicubane single-molecule magnets.

Dinuclear Lanthanide–Carboxylate Compounds: Field-Induced Slow Relaxation of Magnetization for Dysprosium(III) Analogue

Three chiral dinuclear lanthanide compounds, Ln2(µ2-L)4(L)2(phen)2 (Ln = Dy (1), Gd (2), and Er (3); phen = 1,10-phenanthroline), have been synthesized using the (S)-(+)-2-(6-methoxy-2-naphthyl)propionic acid (HL) ligand. The two lanthanide centres in compound Ln2(µ2-L)4(L)2(phen)2 are bridged by four carboxylate groups to give a dinuclear Ln2(µ2-L)4 core. The square antiprismatic coordination environment for each lanthanide centre is further completed by a chelating carboxylate group from another L– ligand and two nitrogen atoms from the phen ligand. A weak antiferromagnetic interaction between the two GdIII ions is observed in compound 2. The Dy analogue displays field-induced slow magnetic relaxation behaviour with an effective energy barrier Ueff/k of 17.24(2) K and a pre-exponential factor τ0 of 2.7(1) × 10–6 s. However, no slow relaxation phenomenon was observed for the Er derivative even in the presence of 2 kOe applied field.

Chiral tetrahedral iron(ii) cages: diastereoselective subcomponent self-assembly, structure interconversion and spin-crossover properties

Tetrahedral chiral iron(ii) cages with spin crossover behaviors can be almost quantitatively formed by one-pot subcomponent self-assembly with high diastereoselectivity. The cage to cage transformation involving imine exchange was discovered.

Cobalt(ii/iii), nickel(ii) and copper(ii) coordination clusters employing a monoanionic Schiff base ligand: synthetic, topological and computational mechanistic aspects

Nine coordination clusters (M = Co^II/III, Ni^II, Cu^II) using a monoanionic Schiff base ligand were synthesized and characterized. A series of transformations occur in the ligand in certain compounds.

Synthesis, crystal structures and magnetic properties of mer-cyanideiron(iii)-based 1D heterobimetallic cyanide-bridged chiral coordination polymers

Two pairs of 1D cyanide-bridged heterometallic chiral enantiomer complexes have been synthesized, structurally characterized and magnetically investigated.

Multi odd–even effects on cell parameters, melting points, and optical properties of chiral crystal solids based on S-naproxen

Chiral solids based on S-naproxen alternatively crystallize in P2₁ and P2₁2₁2₁, respectively, which show the odd–even effects on cell parameters, melting points, and luminescence.

Temperature-controlled polymorphism of chiral CuII–LnIII dinuclear complexes exhibiting slow magnetic relaxation

A family of chiral Cu–Ln dinuclear complexes with two different space groups has been constructed. The temperature-controlled reversible conversion from one chiral single-crystal to another chiral single-crystal with slow magnetic relaxation has been achieved.

Cubane-type {M4O4} (M = CoII, ZnII, CuII) clusters: synthesis, crystal structures, and luminescent and magnetic properties

Three cubane-type {M₄O₄} clusters were synthesized and characterized. Their luminescent and magnetic properties were investigated.

The supramolecular interaction mediated chiral 1D cyanide-bridged metamagnet: synthesis, crystal structures and magnetic properties

Two cyanide-bridged enantiopure one-dimensional single chain complexes, [Mn((R,R)-Salcy)Fe(pcq)(CN)3]2n·1.5nDMF (1) and [Mn((S,S)-Salcy)Fe(pcq)(CN)3]2n·1.5nDMF (2), have been synthesized and structurally characterized. Systematically magnetic investigations show the antiferromagnetic coupling between the cyanide-bridged Mn(III)-Fe(III) centers and the interesting metamagnetic behavior at about 5.0 K resulted from the intermolecular π-π interaction.

A new series of cyanide-bridged heterobimetallic FeIII–FeIII/MnIII/CuII one-dimensional complexes: synthesis, crystal structures, and magnetic properties

Four new cyanide-bridged Fe^III–Fe^III/Mn^III/Cu^II one-dimensional complexes have been assembled using K[Fe(bpdBrb)(CN)₂]·2H₂O (1) as building blocks, and structurally characterized and magnetically investigated.

Butterfly-like enantiomerically homochiral {CoII6CoIII4} clusters exhibiting both slow magnetic relaxation and ferroelectric property

A pair of butterfly-like enantiomerically homochiral [Co^II₆Co^III₄] clusters with both slow magnetic relaxation behaviour and ferroelectric property was synthesized.

Anion-controlled self-assembly of two NLO-active dinuclear and molecular square Cu(ii) enantiomeric pairs: from antiferromagnetic to ferromagnetic coupling

Two dinuclear and molecular square Cu(ii) enantiomeric pairs were obtained, and their magnetic properties are switched from antiferromagnetic to ferromagnetic coupling.

A family of enantiopure FeIII4 single molecule magnets: fine tuning of energy barrier by remote substituent

We report a new family of enantiopure star-shaped Fe^III₄ single-molecule magnets (SMMs). Interestingly, the SMM properties of this series of clusters can be finely tuned by the remote substituent of the ligands.