Synthesis,structure and magnetic properties of a mononuclear Cu(II) complex with a NNO donor Schiff base ligand and its oxalato- and oxamidato-bridged dinuclear complexes

摘要

The Schiff base,N-dimethyl-N'-propylsalicylideneimine (HL) acts as a bidentate as well as a tridentate ligand for copper(II) ions.The mononuclear complex [(HL)2Cu](ClO_4)_2 1 reacts with oxalate or oxamidate anions to give dinuclear complexes [(HL)Cu(n-C_2O_4)Cu(HL)](ClO_4)_2 2,[(HL)Cu(SCN)(mu-C,O_4)(SCN)Cu(HL)] 3,[LCu(fi-C_2O_4)CuL] 4,and [LCu{u-(NH)_2C_2O_2}CuL] 5.Complexes 1,3 and 4 have been structurally characterised.Complexes 2 (previously reported) and 3 are found to be essentially square planar and square pyramidal,respectively,whereas complex 4 shows a structure intermediate between square pyramidal and trigonal bipyramidal geometry.Interconversions between 2,3 and 4 were observed in water,depending upon the pH of the solutions.The cryomagnetic properties of 3,4 and 5 were studied.The magnitude of the exchange coupling has been analysed in the framework of a simple orbital model.