Synthesis and stabilization of a monomeric iron(II) hydroxo complex via intramolecular hydrogen bonding in the secondary coordination sphere.

Utilizing the pyridinediimine ligand [(2,6-(i)PrC(6)H(3))N═CMe)(N((i)Pr)(2)C(2)H(4))N═CMe)C(5)H(3)N] (didpa), the iron(II) complexes Fe(didpa)Br(2) (1), [Fe(Hdidpa)Br(2)][PF(6)] (2), and [Fe(Hdidpa)CH(3)CN(OH)][2PF(6)] (3) were synthesized and characterized by X-ray diffraction and spectroscopic methods. The X-ray data show that the didpa scaffold is capable of forming intramolecular hydrogen bonds in the solid state located within the secondary coordination sphere of complexes 2 and 3. These hydrogen bonds are responsible for stabilizing the iron(II) hydroxo ligand in 3, which originates from H(2)O.