Kinetic Studies of Transition Metal Complexes with Macrocyclic Ligands

Abstract

The preparations of a range of saturated triazamacrocyles are described. The macrocycles vary in ring size, from 9 to 14 members in the position of, the heteroatoms within a ring, and in the number and position, of C-methyl substituents on the ring. The method of cyclisation, from tosylated derivatives of di- and tri - amines, diols and amine diols, results in the formation of a number of by-products a discussion of the cyclisation reaction and the nature of these by-products is presented. Copper (II) complexes of the macrocyclic ligands and of cis, ciscyclohexane-1,3,5-triamine have been prepared and their dissociation reactions with acid have been studied. The reactions of complexes with I [g]aneN3 (1,4,7-triazacyclone), Me[9]aneN3, [10]aneN3, [11]ane-1,4,8-N3 and Me3[12]aneN3 display a linear dependence on hydrogen ion concentration, whereas for complexes of [11]ane-1,4,7-N3,[12]ane-1,4,7-N3, [12]ane-1,5,g-N3, [13]ane-1,5,9-N3, [14]ane-1,5,9-N3 and cis, cis-cyclohexane-1,3,5-triamine a non-linear dependence is observed which tends to acid-independence with increasing [H+] General. acid catalysis of, the dissociation reactions is observed. The reactions are compared with those of copper and nickel complexes of linear polyamines and nickel-triazamacrocycle complexes, and the results obtained in this work are discussed in terms of a general mechanism, originally proposed by Margerum(105), for the dissociation of metal-polyamine complexes.