Pentanuclear Spirocyclic Ni₄Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

Abstract

Five pentanuclear heterometallic isostructural complexes, [Ni4Ln(L)2(LH)2(CH3CN)3Cl]·xH2O·yCH3OH {Ln = YIII (1), GdIII (2), TbIII (3), DyIII (4) and ErIII (5)} [for 1 and 2, x = 2, y = 1; for 3, x = 6, y = 2; for 4, x = 5, y = 1; for 5, x = 2, y = 2] were prepared by the reaction of (E)‐2‐(hydroxymethyl)‐6‐{[(2‐hydroxyphenyl)imino]methyl}‐4‐methylphenol (LH3) with LnCl3·6H2O and Ni(OAc)2·4H2O in the presence of tetrabutylammonium hydroxide (TBA‐OH) base. The structural characterization reveals that compounds 1–5 contain a spirocyclic pentanuclear core [Ni4Ln(µ3‐O)4(µ2‐O)4]3+ where two triangular motifs [Ni2Ln(µ3‐O)2(µ2‐O)2]3+ are fused together through a common vertex of the LnIII ion. The central LnIII ion forms an eight‐coordinated distorted triangular dodecahedron geometry, while the nickel(II) ions form a distorted octahedron geometry. Comprehensive dc magnetic studies reveal that antiferromagnetic exchange interaction exists between the NiII centres. The ac susceptibility measurement revels that dysprosium and erbium analogue shows field induced slow magnetic relaxation with an anisotropic barrier (Ueff) of 25.12 cm–1 and 22.13 cm–1 respectively.

Interplay between anisotropy and magnetic exchange to modulate the magnetic relaxation behaviours of phenoxo bridged Dy2dimers with axial β-diketonate co-ligands

“…In accordance with the current literature review, it emerges that multidentate Schiff base ligands with distinct coordination environments have been effectively applied in the assembly of polynuclear heterometallic 3d/4f 61–75 and homometallic 4f complexes. 57,76–85 Utilizing the above-mentioned knowledge, we have applied ( E )-2-((pyridin-2-ylmethylene)amino)phenol (LH) in order to construct homometallic lanthanide complexes.…”

Effect of diamagnetic Zn(ii) ions on the SMM properties of a series of trinuclear ZnDy2 and tetranuclear Zn2Dy2 (LnIII = Dy, Tb, Gd) complexes: combined experimental and theoretical studies

“…[22][23][24][25][26][27] Among several methodical techniques tried to suppress QTM, one is merging of 3d-4f spin carriers. 13,[28][29][30][31][32][33][34][35][36][37][38][39][40][41] However, some researchers have observed very weak magnetic coupling between paramagnetic 3d and 4f ions which shows a small separation between the low-lying split sublevels leading to a lower energy barrier for magnetization reversal. [35][36][37][38] Keeping this in mind, replacing paramagnetic transition metal M 2+ ions with diamagnetic Zn II ions would be a good approach for enhancing the energy barrier and this method is employed with relative success by many researchers as it diminishes the intermolecular magnetic interaction responsible for swift tunneling of magnetization.…”

Utilization of diamagnetic Zn(II) ion to boost the anisotropic nature of Ln(III) ion in heterodinuclear Zn(II)–Ln(III) single‐molecule magnets

“…In this context, lanthanide ions are advantageous to design and construct building block SMMs as they possess significant magnetic anisotropy, which is the result of a combination of strong spin-orbit coupling and unquenched orbital angular momentum, and may result in weaker crystal field effects when placed in an appropriate ligand field. [26][27][28][29][30] Utilizing this strategy, an enormous number of heterometallic 3d/4f clusters [31][32][33][34][35] and high symmetry with lownuclearity 4f metal complexes [36][37][38][39][40][41] (mostly containing Dy III ions) displaying SMM behavior were designed. Recently, energy barrier (U eff ) up to 2220 K [42] and blocking temperature (T B ) of 80 K [43] are observed for a dysprosium complex.…”