Unsymmetrical Tetradentate Schiff Base Complexes Derived from 2,3-diaminophenol and Salicylaldehyde or 5-bromosalicylaldehyde

• Published in: Transition metal chemistry (Weinheim) 2006-03, Vol.31 (2), p.169-175
• Main Authors: Ourari, Ali, Ouari, Kamel, Moumeni, Wahiba, Sibous, Lakhdar, Bouet, Gilles M., Khan, Mustayeen A.
• Format: Article
• Language: English
• Subjects: Chemical Sciences
• ISSN: 0340-4285; 1572-901X
• DOI: 10.1007/s11243-005-6334-y

Salicylaldehyde or 5-bromosalicylaldehyde reacted with 2,3-diaminophenol in absolute EtOH in a 2:1 molar ratio to give new unsymmetrical Schiff bases (H^sub 2^L). The bases were used as ligands to coordinate Mn(III), Ni(II) and Cu(II) chlorides leading to [Mn^sup III^ClL] · EtOH and [M^sup II^L] or [M^sup II^L] · 2H^sub 2^O (M = Ni or Cu) complexes. Their structures were determined using mass spectroscopy, IR, u.v.-vis and ^sup 1^H-n.m.r. The cyclic voltammetry in acetonitrile showed irreversible waves for both ligands. Under the same experimental conditions, the complexes exhibited mainly the non-reversible reduction of the Ni(II) or Cu(II) ion to Ni(0) or Cu(0), while the reduction of Mn(III) to Mn(II) was found to be a quite reversible phenomenon.[PUBLICATION ABSTRACT]