Nickel(III)-tris(di-imine) complexes: a series of strong one-electron oxidants

• Published in: Canadian journal of chemistry 1981-06, Vol.59 (11), p.1610-1614
• Main Authors: Brodovitch, J. C, Haines, R. I, McAuley, A
• Format: Article
• Language: English
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v81-238

The complexes [Ni(III)(LL) 3 ](ClO 4 ) 3 (LL = phen, bipy, and substituted derivatives) have been isolated as products of the electrolysis in acetonitrile of the corresponding nickel(II) species. Electron spin resonance measurements for all nickel(III) species in frozen anhydrous CH 3 CN and in frozen 4.0 M HClO 4 solutions (77 K) show a single near symmetric line shape (g ≈ 2.10) with fine structures appearing only in the presence of mixed solvent systems. In a CH 3 CN/5% H 2 O glass (77 K) quintets in the and regions are observed consistent with Jahn-Teller distortion expected for a low-spin d 7 system. Ultraviolet-visible spectra are also reported. Electrode potentials for the Ni(LL) 3 3+/2+ couples in CH 3 CN (0.1 M NaClO 4 ) lie in the range 1.51 V (Ni(4,4′-Me 2 bipy) 3 3+ ) to 1.82 V (Ni(5-NO 2 -phen) 3 3+ ) and the powerful oxidizing nature of these species has been confirmed in reaction with both organic and inorganic substrates.