92 research outputs found
Structural disorder in high-spin (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 {CoII[CoII8(pyNO)12(MeOH)12][WV(CN)8]6} (1) and {CoII[CoII8(4-phpyNO)7(MeOH)17][WV(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
Manipulation of the cyanido-bridged rhombus in the crystalline state : co-crystallization, desolvation and thermal treatment
Influence of the substituted ethylenediamine ligand on the structure and properties of solv. compounds
Field-induced slow magnetic relaxation in cluster-based compound
Magnetic measurements of a three-dimensional (3D) molecular magnet built of Mn₉[W(CN)₈]₆ clusters have been carried out to study its static and dynamic properties. Measurements of ac susceptibility in the presence of static magnetic field revealed slow magnetic relaxations. It was found that for the 120 Hz wave frequency the optimal static field which maximizes the imaginary component of the ac susceptibility is about 500 Oe
Site selectivity for the spin states and spin crossover in undecanuclear heterometallic cyanido-bridged clusters
Photo-induced relaxation of magnetization in molecular magnet
The experimental study of photo-induced magnetization of hybrid
molecular magnet containing cobalt(II) and tungsten(V) magnetic centers
bridged by 4,40
-bpy and CN− is presented. The observed increase in magnetization rate is attributed to the defects due to inter-valence transfer between
CoIIWV *) CoIIIWIV. The time evolution of magnetization is parameterized
by the power law rather than exponential function
Rotating magnetocaloric effect in an anisotropic two-dimensional molecular magnet with topological phase transition : experiment and theory
- …