Rearrangement in a Tripodal Nitroxide Ligand To Modulate the Reactivity of a Ti-F Bond

The tripodal nitroxide ligand [(2-(BuNO)-Bu-t)C6H4CH2)(3)N](3-) (TriNOx(3-)) binds the Ti(IV) cation and prevents inner-sphere coordination of chloride in the complex [Ti(TriNOx)]Cl (1). The ligand undergoes an eta(2)-NO to kappa(1)-O rearrangement to enable a fluoride ion to bind in the related complex Ti(TriNOx)F (2). Computational and reactivity studies demonstrated that the ligand rearrangement contributed to the enthalpy change in the transfer of a fluoride anion.