The synthesis, structure and electrochemical properties of new cobalt and nickel complexes based on ferrocenyl-containing o-iminophenols

• Published in: Inorganica Chimica Acta Vol. 495; p. 118963
• Main Authors: Baryshnikova, S.V., Poddel'sky, A.I., Cherkasov, A.V., Smolyaninov, I.V.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2019; Elsevier Science Ltd
• Subjects: Chemical synthesis; Cobalt compounds; Cobalt(II); Diamagnetism; Electrochemical analysis; Ferrocene; Imines; Infrared spectroscopy; Molecular structure; Nickel; Nickel(II); NMR; Nuclear magnetic resonance; o-Iminophenol; Quinones; Single crystals; X ray analysis; X-ray diffraction; X-ray diffraction; Cobalt(II); o-Iminophenol; CV; Nickel(II); Ferrocene
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.118963

[Display omitted] •New cobalt(II) and nickel(II) o-iminophenolato complexes with ferrocene backbone.•The X-ray structure of nickel(II) bis-o-iminophenolate; trans-position of ferrocene groups.•Complexes undergo series of electrochemical oxidations and reductions.•The oxidative addition of o-quinone to Co(II) o-iminophenolate to give Co(III) species. New cobalt(II) and nickel(II) bis-o-iminophenolato complexes of the type (Fc-CHN-ArO)2MII, where M = Co, ArO = C6H4O (1); M = Co, Ar = 4,6-tBu-C6H2O (2); M = Ni, Ar = 4,6-tBu-C6H2O (3), have been synthesized by the reaction of ferrocenyl-containing Schiff bases Fc-C(H)N-(C6H4)OH and Fc-C(H)N-(4,6-tBu-C6H2)OH with cobalt(II) chloride and nickel(II) acetate in methanol solution in the presence of base. Complexes 1–3 have been characterized in details by IR-spectroscopy, mass-spectrometry, cyclic voltammetry and NMR-spectroscopy (for 3). The molecular structure of nickel complex 3 in crystalline state was determined by single-crystal X-ray analysis. Nickel(II) complex 3 is diamagnetic and has a well-resolved NMR spectrum. Cobalt complexes 1 and 2 are paramagnetic. Their interaction with 3,6-di-tert-butyl-o-benzoquinone leads to new cobalt(III) o-benzosemiquinone complexes of the type (Fc-CHN-ArO)2MIII(3,6-DBSQ) 1a and 2a, respectively (3,6-DBSQ is 3,6-di-tert-butyl-o-benzosemiquinone) possessing a doublet spin state with resolved EPR spectra.