Cobalt(III) Bis-o-semiquinone Complexes with 1-Aryl-3,5-Diphenylformazan Ligands: Synthesis, Structures, and Magnetic Properties

• Published in: Russian journal of coordination chemistry Vol. 47; no. 10; pp. 687 - 694
• Main Authors: Protasenko, N. A., Poddelskii, A. I., Rumyantsev, R. V., Yakushev, I. A., Cherkasov, V. K.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-10-2021; Springer Nature B.V
• Subjects: Anions; Antiferromagnetism; Bromine; Chemical synthesis; Chemistry; Chemistry and Materials Science; Chlorine; Cobalt compounds; Coordination compounds; Ferromagnetism; Fluorine; Inorganic Chemistry; Iodine; Ligands; Magnetic properties; Molecular structure; Physical Chemistry; Structural analysis; semiquinone; cobalt(III) complexes; formazan; X-ray structure analysis; magnetochemistry
• ISSN: 1070-3284; 1608-3318
• DOI: 10.1134/S1070328421100067

New heteroligand cobalt(III) bis-3,6-di-
tert
-butyl-
o
-benzosemiquinone complexes with 1-(
p
-X-phenyl)-3,5-diphenylformazan ligands Co(3,6-SQ)
2
L
X
(Х is fluorine (
I
), chlorine (
II
), bromine (
III
), iodine (
IV
), and methyl (
V
)) are synthesized. The molecular structures of compounds
I
,
II
, and
IV
are determined by X-ray structure analysis (CIF files CCDC nos. 2060727 (
I
), 2052592 (
II
), and 2060728 (
IV
)). The coordination environment of the central cobalt ion in the studied complexes is a weakly distorted octahedron, and the degree of distortion insignificantly changes depending on the substituent. According to the X-ray structure data and results of magnetic and spectral studies, compounds
I
–
V
are low-spin complexes of cobalt(III) bound to two radical anion
o-
semiquinone ligands and one formazan anion. The magnetic behavior of complexes
I
–
V
in a temperature range of 50–300 K is characterized by the predomination of intramolecular exchange interactions of the antiferromagnetic type, whereas in the range lower than 50 K complexes
II
–
V
exhibit ferromagnetic ordering caused by intermolecular exchange interactions between the paramagnetic ligands.