The coordination of a mono(amido) triamine macrocyclic ligand Me₃TACD derived from cyclen (1,4,7,10-tetraazacyclododecane or [12]aneN₄) toward electropositive metal centers is surveyed. This NNNN-type monoanionic macrocyclic ligand is capable of stabilizing a variety of metal coordination environments that are commonly not amenable to stable coordination spheres. Metal complexes supported by Me₃TACD include hydrides, hydrocarbyls, silyls, and amides. Protection of one hemisphere of a large metal center allows, as in the case of metallocene scaffolds for early transition metals, deaggregation and control of reactivity.