Metal chelates of dithiocarbazic acid and its derivatives. VII. The magnetism of some copper(II) complexes of salicylaldehyde Schiff bases derived from N-methyl- S-methyldithiocarbazate and S,S′-dimethyldithiocarbazate

Abstract

The Schiff bases α- N-methyl-{S}-methyl-β- N-(2-hydroxyphenyl)methylendithiocarbazate o-HO.C 6H 4.CH = NNMeC(=S)SMe (HONMeS), its 3-methoxy derivative (3-MeOHONMeS), 1-(2-hydroxyphenyl)-2,3-diaza-4-methylthio-5-thiahexa-1,3-diene, o-HO.C 6H 4.CH = NNC(SMe) 2 (HONSMe) and its 5-chloro and 5-bromo derivatives (5XHONSMe; X = Cl, Br) were prepared. By the loss of a proton the Schiff bases act as uni-negatively charged ONS tridentate ligands. The complexes Ni(ONMeS)X (X = Cl, Br, NCS) are diamagnetic and square-planar, while the complex Ni(ONMeS) 2 is paramagnetic and octahedral. The palladium complex Pd(ONSMe)Cl was also isolated. the copper complexes Cu(ONMeS)NO 3, Cu(ONSMe)NO 3, and [Cu(ONMeS)py]ClO 4 display normal magnetic behaviour. The compound Cu(ONMeS)BF 4 has an anomalously low moment (0.88 B.M.) at room temperature and the moment decrease to 0.38 B.M. at 93°K due to antiferromagnetic interaction. The compound Cu 2(3MeOONMeS)Cl 3 also displays antiferromagnetic interaction between the two copper atoms of the dimer. The complexes Cu 3(ONMeS) 2Cl 4 and Cu 3(ONSMe) 2Cl 4 most likely have a linear trimeric structure; the magnetic data for the latter compound fit an equation for a linear trimer with three antiferromagnetically interacting copper atoms. The compounds Cu(5ClONSMe)Cl and Cu(5BrONSMe)Cl are monomeric with normal magnetic moments.