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

The tripodal nitroxide ligand [(2-tBuNO)­C6H4CH2)3N]3– (TriNOx3–) binds the Ti­(IV) cation and prevents inner-sphere coordination of chloride in the complex [Ti­(TriNOx)]Cl (1). The ligand undergoes an η2-NO to κ1-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.