Diversity in the reactions of unsymmetric dinucleating Schiff baseligands with CuII and NiII

Abstract

A diversity of reaction products have been found in the reactions of two related unsymmetrical Schiff base dinucleating ligands, HL¹ and HL², derived from 3-chloromethyl-5-methylsalicylaldehyde 1, with copper(II) and nickel(II) salts. The ligands remain intact in the copper(II) complexes to give the homodinuclear complexes [Cu₂L¹Br₃] 2 and [Cu₂L²(OH)(ClO₄)]ClO₄3, the crystal structures of which have been solved. The reactions of HL¹ and HL² with nickel perchlorate led to hydrolysis of the imine bond. With HL¹ the homodinuclear complex [NiL^A(OH₂)]₂[ClO₄]₂·4H₂O was formed and with HL² hydrolysis was followed by elimination of C₂H₄ from the terminal NEt₂ of the iminic side arm to leave an NHEt group and the dinuclear complex [NiL^C(OH₂)]₂[ClO₄]₂·3CH₃OH. The crystal structures of the two nickel complexes are also reported.