Chemistry of re with N,N'-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.