Sukhen Bala

The synthesis of lanthanide complexes with low coordination numbers is challenging because the large ionic radii of lanthanide ions generally promote the formation of highly coordinated species. Achieving lower coordination geometries requires introducing significant steric hindrance. We report two low coordinated, almost perfectly octahedral lanthanide complexes [LnIII(Ph3PO)4(HBS)2](OTf) (Ln = DyIII (1), YbIII (2) and NdIII (3), Ph3PO = triphenylphosphine oxide; HBS = 4-hydroxybenzenesulfonate). Their magnetic and temperature-dependent luminescent properties have been systematically investigated showing field induced Single Molecule Magnet behavior and f-f optical transitions. To rationalize these properties with Complete Active Space Spin Orbit Configuration Interaction calculations, we have extended our program to compute magnetic dipole oscillator strengths. We showed that the octahedral ligand field acts as the magnetic main axes, that small geometric distortions induce significant anisotropy and simulated luminescent and magnetic data in very good agreement with experiment.

The current work aims to generate multifunctional MOFs by incorporating a well-known inorganic motif, a trinuclear Cu-pyrazolate [Cu₃(μ₃-OH)(μ-Pyz)₃] (T-CuP) unit, as a node of the network.

The present communication deals with the synthesis, characterization of a Cr-based metallogel and explores its electrical-magnetic properties. The proton conductivity and toxic dye sequestrations have also been investigated.

Three fascinating interlocked highly stable triacontanuclear giant nanocages were synthesized and structurally and microscopically characterized. The strong antiferromagnetic behaviour can be envisaged as a silver lining in generating elusive molecular nanomagnets.

Hysteretic four-step spin crossover behaviour with the sequence of LS ↔ HS _0.25 LS _0.75 ↔ HS _0.5 LS _0.5 ↔ HS _0.67 LS _0.33 ↔ HS is observed for the first time.

The present work is part of our ongoing quest for developing multifunctional lanthanide–organic hybrid materials using non-conventional soft N-rich pyridyl–pyrazole-based ligands. Accordingly, we have embarked on an interesting venture of generating lanthanide-metal–organic frameworks (MOFs) using a new N-rich compartmental type ligand. It is imperative to note that compartmental ligands are seldom used in MOF synthesis, let alone lanthanide-MOFs. The terminals of the newly designed titular ligand comprise two contrasting functional moieties, a hard carboxylic group and a soft chelating pyridyl–pyrazole moiety. Their contrasting coordination behaviours are manifested in two isostructural lanthanide-based MOFs (Ln = Gd (1), Dy (2)). Single crystal X-ray analyses reveal archetypal graphite-like framework formation containing substantial pores inside the network with a corresponding moderately high surface area and N₂ and CO₂ gas sorption properties. Another important aspect of lanthanide-MOFs is magnetism and the results of the present work are highly encouraging. The occurrence of the magnetocaloric effect (MCE) of mononuclear Gd-based MOF-1 further boasts the notion of generating magnetic materials. Dy-based MOF-2, on the other hand, features single ion magnet (SIM) behavior, as further confirmed by ac susceptibility measurements.

A stable and high-performance molecule displays a reversal barrier >900 K, which is the highest among square antiprismatic dysprosium single-ion magnets.

In this article, we report four pyridyl‐pyrazolyl based polynuclear cluster complexes with Ln ₈ {Ln=[Gd ^III ₈ (μ ₃ ‐OH) ₄ (L ₁ ) ₄ (DEA) ₄ Cl ₄ ](DMF) ₂ (MeOH)( 1) , [Ho ^III ₈ (μ ₃ ‐OH) ₄ (L ₁ ) ₄ (DEA) ₄ Cl ₄ ]( 2) , [Er ^III ₈ (μ ₃ ‐OH) ₄ (L ₁ ) ₄ (DEA) ₄ Cl ₄ ](DMF)(MeOH)(H ₂ O)( 3 ), [Yb ^III ₈ (μ ₃ ‐OH) ₄ (L ₁ ) ₄ (DEA) ₄ Cl ₄ ](DMF)(MeOH)( 4 ) [DEA = Diethanolamine] cores. The impetus for this study was to explore the magnetic behaviour of lanthanide ions which are often ignored or overlooked. X‐ray crystal analysis show that these complexes are isostructural and exhibit an interesting butterfly like topology. The semi‐rigidity and asymmetric nature of the ligand led to different coordination environment around the metal centres. The lanthanide ions adopt two types of geometry, a bicapped trigonal prism and a distorted square antiprismatic geometry around the metal center. Such dissimilar coordination environments around the lanthanide centre can have profound effects on their magnetic behaviour. Indeed, the magnetic measurements revealed significant magnetocaloric effect for octanuclear gadolinium complex 1 with magnetic entropy change (−ΔS _m ) of 31.4 J kg ⁻¹ K ⁻¹ for ΔH = 9 T at T = 3 K whereas Er analogue complex 3 displayed SMM behavior.