Structural Disorder in High-Spin {Co II 9 W V 6 } ( Core )-[Pyridine N-Oxides] ( Shell ) Architectures

• Published in: Molecules (Basel, Switzerland) Vol. 25; no. 2; p. 251
• Main Authors: Liberka, Michal, Kobylarczyk, Jedrzej, Podgajny, Robert
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08-01-2020; MDPI
• Subjects: Aromatic compounds; Chelation; crystal engineering; Crystallization; Crystals; Cyanides; Ferromagnetism; Hydrogen bonds; Infrared spectroscopy; Ligands; magnetic coordination materials; Magnetic induction; Magnetic properties; Magnetic relaxation; Magnetic studies; Magnetism; molecular disorder; octacyanidometalates; polynuclear clusters; Pyridines; Solvents; Spectroscopy; surface decoration; octacyanidometalates; surface decoration; magnetic coordination materials; molecular disorder; polynuclear clusters; crystal engineering
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25020251

The combinations of Co(II), octacyanidotungstate(V), and monodentate pyridine
-oxide (pyNO) or 4-phenylpyridine
-oxide (4-phpyNO) led to crystallization of novel crystalline phases {Co
[Co
(pyNO)
(MeOH)
][W
(CN)
]
} (
) and {Co
[Co
(4-phpyNO)
(MeOH)
][W
(CN)
]
}·7MeOH·(4-phpyNO)
(
). In both architectures, metal-cyanide clusters are coordinated by
-oxide ligands in a simple monodentate manner to give the spherical objects of over 1 nm core diameter and about 2.2 nm (
) and 3 nm (
) 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
, the π-π interactions between the pyNO ligands attached to the same metal centers are suggested for the first time. In
, 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 M
M'
-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.