Metal specific variable binding modes in Schiff base complexes - facile synthesis and crystal structure of anionic bis-N-(2-oxyethyl-5-bromosalicylal-diminato) cobalt(III)

The Schiff bases N-(2-hydroxyethyl)-X-salicylaldimine (X = H, Br) which sho w monobasic bidentate binding mode in their copper(II) complexes, in contra st offer dibasic tridentate chelation and almost spontaneous reaction leadi ng to the synthesis of anionic bis-tridentate cobalt(III) chelates. On the other hand the Schiff bases N-(2-hydroxyphenyl)-X-salicylaldimine (X = H, B r) which are in dibasic tridentate binding mode in their copper(II) complex es are involved in monobasic bidentate chelation yielding neutral bis-biden tate cobalt(TI) complexes. Crystal structure analysis of bis-N-(2-oxyethyl- 5-bromosalicylal-diminato) cobalt(III) anion confirms near perfect octahedr al geometry around cobalt(III). (C) 2001 Elsevier Science B.V. All rights r eserved.