Remote Multiproton Storage within a Pyrrolide‐Pincer‐Type Ligand

A chemically non‐innocent pyrrole‐based trianionic (ONO) 3− pincer ligand within [(pyr‐ONO)TiCl(thf) 2 ] ( 2 ) can access the dianionic [(3 H ‐pyr‐ONO)TiCl 2 (thf)] ( 1‐THF ) and monoanionic [(3 H ,4 H ‐pyr‐ONO)TiCl 2 (OEt 2 )][B{3,5‐(CF 3 ) 2 C 6 H 3 } 4 ] ( 3‐Et 2 O ) states through remote protonation of the pyrrole γ‐C π‐bonds. The homoleptic [(3 H ‐pyr‐ONO) 2 Zr] ( 4 ) was synthesized and characterized by X‐ray diffraction and NMR spectroscopy in solution. The protonation of 4 by [H(OEt 2 ) 2 ][B{C 6 H 3 (CF 3 ) 2 } 4 ] yields [(3 H ,4 H ‐pyr‐ONO)(3 H ‐pyr‐ONO)Zr][B{3,5‐(CF 3 ) 2 C 6 H 3 } 4 ] ( 5 ), thus demonstrating the storage of three protons.