Tridentate Coordination of Monosubstituted Derivatives of the Tris(2-pyridylmethyl)amine Ligand to FeCl3: Structures and Spectroscopic Properties of ((2-Bromopyridyl)methyl)bis- (2-pyridylmethyl)amine FeIIICl3 and (((2-p- Methoxyphenyl)pyridyl)methyl)Bis(2-pyridyl- methyl)]amine FeIIICl3 and Comparison with the Bis(2-pyridylmethyl)]amine FeIIICl3 Complex

In trichloroferric complexes with tris(2-pyridylmethyl)amine ligands α-substituted by bulky groups, tridentate coordination of the tripode is observed. The X-ray crystal structures of the complexes ((2-bromopyridyl)methyl)bis(2-pyridylmethyl)amine FeIIICl3 and (((2-p-methoxyphenyl)pyridyl)methyl)bis(2-pyridylmethyl)amine FeIIICl3 are reported and compared with that of the bis(2-pyridylmethyl)]amine FeIIICl3 complex. The substituted pyridyl arm remains uncoordinated both in the solid state and in solution, as shown by NMR measurements.