Chemistry of Re with <i>N</i>,<i>N</i>‘-Bis(2-pyridylmethyl)ethylenediamine (H₂pmen): Hydrolysis, Dehydrogenation, and Ternary Complexes

A number of Re complexes with N,N‘-bis(2-pyridylmethyl)ethylenediamine (H2pmen) have been made from [NH4][ReO4]. [ReOCl2(H2pmen)]Cl, [ReOCl(Hpmen)][ReO4], and [ReO2(H2pmen)][ReO4] are related by hydrolysis/HCl substitution. [ReOCl(Hpmen)][ReO4] was structurally characterized and found to contain a water-stable amido−Re bond. Dehydrogenation of the N-donor ligand from each amine to imine with concomitant two-electron reduction of the Re center occurs readily in these systems. With suitable 3-hydroxy-4-pyrones, ternary complexes such as [ReIIICl(ma)(C14H14N4)][ReO4]·CH3OH, 5, were made from [NH4][ReO4], H2pmen·4HCl and pyrones in one-pot syntheses. 5, a seven-coordinate ReIII complex, was structurally characterized.