The preparation of the α-iodo-substituted tripods within the series of tris(2-pyridylmethyl)amine ligands, and the characterization of the corresponding I1–3TPAFeCl2 complexes

We report in this communication the easy preparation of the α-iodo substituted tripods within the series of tris(2-pyridylmethyl)amine ligands, I1TPA, I2TPA and I3TPA, respectively. The characterization of the corresponding FeCl2 complexes in solution is described and structural analysis by X-ray diffraction for I1TPAFeCl2 and I2TPAFeCl2 is also reported. The steric effect of the iodo substituent is evidenced: (i) by elongation of the metal to iodo-pyridine distance within I1TPAFeCl2, which however remains a very stable compound; (ii) by decoordination of one substituted pyridine in I2TPAFeCl2 and I3TPAFeCl3. In I2TPAFeCl2 and in the solid state, this uncoordinated pyridine strongly interacts with the same fragment of the neighbouring molecule, providing an overall dinuclear arrangement for this complex.