Significant electron-transfer reactions by redox-active transition metals often function by participating with redox-inactive metals to facilitate reactivity. Examples can be seen in synthetic and biological systems such as the potassium-promoted iron surfaces used in the Haber-Bosch process, or the Ca<sup>2+</sup> ion in the oxygen evolving complex of photosystem II. Inclusion of these redox-inactive Lewis acids have been shown to enhance electron-transfer rates and tune reduction potentials in synthetic chemical systems. In this work, we set out to design this feature into the redox non-innocent pyridinediimine (PDI) scaffold by synthesizing a family of Iron (II) pyridinediimine complexes with a 15-crown-5 ether moiety located in the secondary coordination sphere, leading to redox active metal-ligand complexes with Lewis acids in the secondary sphere. We report here the synthesis and characterization of these complexes, as well as kinetic studies which have demonstrated modest enhancement in reaction kinetics by luring in reactive anion species.

Enticing anion reduction with Lewis acids in the secondary coordination sphere of iron (II) pyridinediimine complexes

255th National Meeting (2018)

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