Synthesis and Copper(I) Complexes of a Series of 9- to 13-Membered N3 Macrocycles

Eight cyclic triamines with ring sizes between 9 and 13 were synthesized by the p-toluenesulfonate method. The open-chain triamines bis(2-aminoethyl)amine (dien) and bis(3-aminopropyl)amine (diprop) were used as starting materials. In some cases, the corresponding dimeric cyclic hexaamines have been isolated and characterized as major by-products. The complexation of Cu(I) by the triamines has been studied potentiometrically in CH₃CN/H₂O. All ligands L form ternary complexes Cu(CH₃CN)L]⁺. The corresponding association constants vary between 10¹¹ and 10⁷, decreasing with increasing ring size. In addition, complexes Cu(CH₃CN)_yLH]²⁺, y = 1 or 2, are found as less important species with maximum concentrations of 7 to 50%.