1,8-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-4,11-dibenzyl-1,4,8,11-tetraazacyclotetradecane

A cyclam (1,4,8,11-tetraazacyclotetradecane)-based macrocycle bearing two benzyl and two 2-hydroxy-3,5-di-tert-butylbenzyl pendent arms was synthesized and characterized using spectroscopic techniques and single crystal X-ray diffraction. The macrocycle crystallizes in the triclinic space group P-1, with the asymmetric unit containing one-half of the molecule. The structure is stabilized by hydrogen-bonding which exists between the phenolic protons and the nitrogen atoms of the macrocyclic ring. The presence of this hydrogen bonding is observed in the 1H-NMR due to the deshielded nature of the phenolic OH peak (δ 9.99). Cyclic voltammetry of the ligand revealed a single quasi-reversible peak at −0.58 V (Epc = −0.48 V and Epa = −0.68 V), which is due to the electrochemical oxidation of the phenol to the phenoxyl radical.