Stabilization of Aryl-Calcium, -Strontium, and -Barium Compounds by Designed Steric and π-Bonding Encapsulation

Pentafluorophenyl complexes of the heavier alkaline‐earth metals (Ca, Sr, Ba) are stabilized by a novel sterically crowded triazenido ligand. The pendent arene rings of the aryl‐substituted triazenide are π bonded to the alkaline‐earth metal atoms, thereby suppressing decomposition pathways or ligand redistribution reactions and allowing the isolation of solvent‐free derivatives (see picture; Ba: green; N: blue; F: light green; C: gray).