Structural Transformation of Copper Coordination Complexes with Inducing Supramolecular Chirality

Four copper coordination complexes [CuL(CH3OH)]n (1), [CuL(C2H5OH)]n (2), [(CuL)·0.5H2O]n (3), and [CuL(H2O)·0.5H2O]n (4) with a tridentated Schiff base ligand (H2L = (E)-2-((4-fluoro-2-hydroxybenzylidene)amino)acetate) were obtained in different solvents and reaction times....

A novel three-dimensional tetranuclear CoII coordination polymer with water hexamers based on the V-shaped tetracarboxylate ligand 4-(2,4-dicarboxylatophenoxy)phthalate

A new coordination polymer (CP), namely, poly[[diaquatris[μ₂-1,4-bis(1H-imidazol-1-yl)benzene]bis[μ₆-4-(2,4-dicarboxylatophenoxy)phthalato]tetracobalt(II)] hexahydrate], {[Co₄(C₁₆H₆O₉)₂(C₁₂H₁₀N₄)₃(H₂O)₂]·6H₂O}_n, has been synthesized by solvothermal reaction. The CP was fully characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single-crystal X-ray diffraction. It presents a three-dimensional (3D) structure based on tetranuclear Co^II secondary building units (SBUs) with a tfz-d net and point symbol (4³)₂(4⁶·6¹⁸·8⁴). The 4-(2,4-dicarboxyphenoxy)phthalic acid (H₄dcppa) ligands are completely deprotonated and link {Co₄(COO)₄}^4- SBUs into two-dimensional (2D) layers. Furthermore, adjacent layers are connected by 1,4-bis(1H-imidazol-1-yl)benzene (bib) ligands, giving rise to a 3D supramolecular architecture. Interestingly, there are numerous elliptical cavities in the CP where isolated unique discrete hexameric water clusters have been observed. The results of thermogravimetric and magnetic analyses are described in detail.

Structural Disorder in High-Spin {CoII9WV6} (Core)-[Pyridine N-Oxides] (Shell) Architectures

The combinations of Co(II), octacyanidotungstate(V), and monodentate pyridine N-oxide (pyNO) or 4-phenylpyridine N-oxide (4-phpyNO) led to crystallization of novel crystalline phases {Co^II[Co^II₈(pyNO)₁₂(MeOH)₁₂][W^V(CN)₈]₆} (1) and {Co^II[Co^II₈(4-phpyNO)₇(MeOH)₁₇][W^V(CN)₈]₆}·7MeOH·(4-phpyNO)₃ (2). In both architectures, metal-cyanide clusters are coordinated by N-oxide ligands in a simple monodentate manner to give the spherical objects of over 1 nm core diameter and about 2.2 nm (1) and 3 nm (2) of the total diameter, terminated with the aromatic rings. The supramolecular architecture is dominated by dense and rich π-π interaction systems. Both structures are characterized by a significant structural disorder in ligand shell, described with the suitable probability models. For 1, the π-π interactions between the pyNO ligands attached to the same metal centers are suggested for the first time. In 2, 4-phpyNO acts as monodentate ligand and as the crystallization molecule. Magnetic studies indicate the high-spin ground state due to the ferromagnetic interactions Co(II)-W(V) through the cyanido bridges. Due to the high symmetry of the clusters, no signature of slow magnetic relaxation was observed. The characterization is completed by solid-state IR and UV-Vis-NIR spectroscopy. The conditions for the stable M₉M'₆-based crystals formation are synthetically discussed in terms of the type of capping ligands: monodentate, bridging, and chelating. The potential of the related polynuclear forms toward the magnetism-based functional properties is critically indicated.

A lanthanide(iii) dodecanuclear structure with a acylhydrazone Schiff-base ligand: slow magnetic relaxation and magnetocaloric effects

In the complex synthesis process, the design of new type structures of lanthanide clusters with high nuclearity provides an opportunity to understand the nature of magnetic dynamics.

A heterotrimetallic synthetic approach in versatile functionalization of nanosized {MxCu13–xW7}3+ and {M1Cu8W6} (M = Co, Ni, Mn, Fe) metal–cyanide magnetic clusters

The addition of 3d metal heteroatom into Cu^II(Me₃tacn)[W(CN)₈]ⁿ⁻ cluster system governs its structural and magnetic features.

Modulation of the FeII spin crossover effect in the pentadecanuclear {Fe9[M(CN)8]6} (M = Re, W) clusters by facial coordination of tridentate polyamine ligands

N,N,N-tridentate ligands coordinated to {Fe₉[M(CN)₈]₆} (M = Re, W) induce the spin crossover on the external Fe sites of the cluster.

Structural anisotropy of cyanido-bridged {CoII9WV6} single-molecule magnets induced by bidentate ligands: towards the rational enhancement of an energy barrier

{CoII9[W^V(CN)₈]₆} clusters capped by odd and even number of bidentate ligands reveal the improved slow magnetic relaxation due to the significant structural anisotropy.