Anion and cation binding by a pendant arm cyclam and its macrobicyclic derivatives

Abstract

A series of transition-metal complexes of N,N′,N″,N‴-tetra(3-hydroxypropyl)cyclam (L¹) are reported. The X-ray structures of the compounds reveal pendant arm coordination of one of the alcohol groups to give square-pyramidal metal centres with simultaneous hydrogen bonding to the counter anions. Ligand L¹ has been elaborated to form a series of macrotricyclic derivatives that form 1 ∶ 1 complexes with Cu(II) and Ni(II). The X-ray structure of the tetrahydrate and protonated forms of L¹ are also reported.