What is "cyclam"

Cyclam (1,4,8,11-tetraazacyclotetradecane) is an organic compound with the formula (NHCHCHNHCHCHCH). It is a white solid that is soluble in water. The compound is notable as a macrocyclic ligand, which binds strongly to many transition metal cations. The compound was first prepared by the reaction of 1,3-dibromopropane and ethylenediamine.

The compound features four secondary amines. Its complexes therefore can exist as several diastereomers, depending on the relative orientation of the N–H centres. Its complexes feature alternating five- and six-membered chelate rings. The closely related ligand cyclen ((CHCHNH)) forms only five-membered CNM chelate rings and tends not to form square-planar complexes.