Europium‐Based Dinuclear Triple‐Stranded Helicate vs. Tetranuclear Quadruple‐Stranded Helicate: Effect of Stoichiometric Ratio on the Supramolecular Self‐Assembly

Abstract

Two europium-based helicates, namely the dinuclear triplestranded helicate [Eu 2 L 3 ] (1) and tetranuclear quadruplestranded helicate [Eu 4 L 4 (NO 3 )] 3+ (2), were achieved by the self-assembly of the succinohydrazone derived bis-tridentate ligand (H 2 L) and Eu 3+ ions in 1:1 and 1:2 ratios, respectively. Both the helicates were characterized by single-crystal X-ray analysis. Structural analysis of both the helicates revealed optically inactive 50:50 mixtures of left-(Λ) and right-hand (Δ) helicates in one unit cell. In 1, both the europium centers [a]

Lanthanide(III) Hexanuclear Circular Helicates: Slow Magnetic Relaxation, Toroidal Arrangement of Magnetic Moments, and Magnetocaloric Effects

“…The torsional angles between two −(O)­CCH 2 CH 2 CH 2 C­(O)– units in each ligand strand are in the range of 62.79–69.46°. It is worth mentioning that the angles of the two −C­(O)­NH– functions within one ligand strand are 4.21–7.82°, which are smaller than the values previously reported for tetranuclear and dinuclear helicates , (Table ). This arrangement is further supplemented by significant intramolecular hydrogen-bonding interactions between the hydrazide H atoms [NNHC­(O)−] and the methoxy O atoms as well as the phenolate O atoms of the adjacent L 2– ligands (Figures S4 and S5).…”

Coordination-Directed Self-Assembly of Functional Polynuclear Lanthanide Supramolecular Architectures

“…The assembled structures can also be modulated by the ligands/metal stoichiometries. 174 zigzag polymeric chain to Ln n L n (n = 2, 3, 4) macrocycles, depending on the base and metal ions. 176 In 2021, Cui, Liu, and co-workers constructed a series of nonclassical polyhedra with missing edges or vertices through the introduction of steric hindrance between organic linkers.…”

“…Furthermore, the NO 3 – ions induced a structural transformation from circular helicate to quadruple-stranded helicate, suggesting the more potent structure regulation ability. The assembled structures can also be modulated by the ligands/metal stoichiometries . Reactions of 128 with Eu­(NO 3 ) 3 ·6H 2 O in 1:1 and 1:2 ratio gave a dinuclear triple-stranded helicate Eu 2 ( 128 -2H) 3 and tetranuclear quadruple-stranded helicate [Eu 4 ( 128 -2H) 4 (NO 3 )] 3+ , respectively.…”

Complexes of Metals With Dihydrazones of Succinic Acid Dihydrazide

“…Complexes of metals with salicylidene dihydrazones succin acid dihydrazide exhibit catalytic activity in the oxidation reaction of alkenes [1], are able to bind to DNA [2], and possess antimicrobial activity [3]. Salicyliden dihydrazone dihydrazide succinic acid, like dihydrazone derivatives of other dibasic acids, is potentially hexadentate and 4 anionic, due to deprotonation of two phenolic hydroxyls and two enolic groups, as in structure E. [9], helicate clusters of lanthanides and the influence of anions on their configuration [10] and dimeric and polymer complexes of Sn [11] were also obtained.…”