A series of dinuclear lanthanide(III) complexes having general formulae [Ln2L2(thd)4] ⋅ 2CH3CN {Ln=DyIII(1), TbIII(2), GdIII(3), ErIII(4)} were successfully synthesized using Schiff base (E)‐2‐((pyridin‐2‐ylmethylene)amino)phenol (LH) and co‐ligand 2,2,6,6‐Tetramethyl‐3,5‐heptanedione (Hthd). The single crystal XRD data shows that complexes possess a dinuclear planar [Ln2(μ2‐O)2]4+ core where phenolate oxygen atoms act as bridges between the two LnIII ions, and that the coordination sphere of LnIII with eight coordination has distorted trigonal dodecahedron geometry. The magnetic analysis shows complex 1 is a single molecule magnet having a zero‐field effective energy barrier (Ueff) of 54.02 K and relaxation time of τo=4.45×10−6 s. Field‐induced SMM behavior has been observed for 4 with an effective energy barrier of 26.9 K and τ0=2.4×10−9 s. CASSCF+RASSI‐SO calculations on 1, 2 and 4 provide deep insight regarding the electronic structure and single‐ion anisotropy of lanthanide ions. Further, using state‐of‐the‐art ab initio calculations, the nature of magnetic anisotropy and magnetic exchange interaction between the LnIII centers is analyzed to shed light on the magnetic dynamics of all the complexes 1–4.

A series of dimetallic Zn II -Ln III compounds of general formulae [LnZn (L) 3 (NO 3 ) 2 ]Á2CH 3 OH (Ln III = Dy III (1), Tb III (2), Gd III (3)) was prepared by stepwise reaction of compartmental ligand LH = ((E)-2-((pyridin-2-ylmethylene)amino)phenol) with Ln (NO 3 ) 3 ÁxH 2 O and Zn (NO 3 ) 2 ÁxH 2 O in the presence of triethylamine as base. The single crystal XRD analysis indicated that both metallic ions are connected to each other through phenolic oxygen atom from fully deprotonated ligand. Based on the SHAPE analysis, the Dy III ion has nine coordination numbers with distorted spherical capped square antiprism geometry, while the Zn II ion has six coordination numbers with distorted octahedral geometry. DC magnetic studies reveal the existence of antiferromagnetic inter-

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.

A new family of 3d-4f polynuclear cocrystals [LnZn 2 L 2 (CH 3 CO 2 ) 4 ]•[Zn 2 Cl 4 L]•H 2 O [where Ln III = Gd(1), Tb(2), and Dy(3)] are synthesized by the sequential reaction of a tetradentate multisite coordinating compartmental ligand, i.e., (E)-2methoxy-6-(((pyridine-2-ylmethyl)imino)methyl)phenol, in the presence of LnCl 3 •6H 2 O and Zn(OAc) 2 •2H 2 O.The detailed studies involve mainly synthesis, structure, and magnetic properties of three isostructural cocrystals. The X-ray diffraction analysis reveals that complexes 1−3 crystallize in triclinic crystal system with the P1̅ space group. The dimeric [Zn 2 Cl 4 L] − complex appears as a cocrystal in the vicinity of the [LnZn 2 L 2 (CH 3 CO 2 ) 4 ] + crystal structure to counter balance the overall charge on the primary coordination sphere. Magnetic relaxation studies indicate that zero-field out-of-phase magnetic susceptibility signals are observed only for complex 3 (Dy III analogue) which gets well resolved in the presence of a H dc = 0.5 kOe magnetic field. The extracted effective energy barrier (U eff ) and pre-exponential factor (τ 0 ) for 3 is found to be 13.53 K and 1.78 × 10 −6 s, respectively. The appearance of single-ion magnet properties for 3 is rationalized with CASSCF/SO-RASSI/SINGLE_ANISO based ab initio calculations.

A series of Schiff base LH ((E)-2-((pyridin-2-ylmethylene)amino)phenol) supported phenoxo bridged symmetric [Dy2(L)2(hfac)4] (1), [Dy2(L)2(tfac)4] (2) and asymmetric [Dy2(L)2(thd)3(NO3)]·1.5H2O (3) binuclear complexes were isolated using diffrently substituted β-diketonate co-ligands (Hhfac =...