Additive-Free Formic Acid Dehydrogenation Catalyzed by a Cobalt Complex

Abstract

The reversible storage of hydrogen through the intermediate formation of Formic Acid (FA) is a promising solution to its safe transport and distribution. However, the common necessity of using bases or additives in the catalytic dehydrogenation of FA is a limitation. In this context, two new cobalt complexes (<b>1</b> and <b>2</b>) were synthesized with a pincer PP(NH)P ligand containing a phosphoramine moiety. Their reaction with an excess FA yields a cobalt(I)-hydride complex (<b>3</b>). We report here the unprecedented catalytic activity of <b>3</b> in the dehydrogenation of FA, with a turnover frequency (TOF) of 4000 h<sup>-1</sup> and a turnover number (TON) of 454, without the need for bases or additives. A mechanistic study reveals that the ligand has a non-innocent behaviour due to intermolecular hydrogen bonding, which is influenced by the concentration of formic acid

Mechanistic Insights into Formic Acid Dehydrogenation and Carbon dioxide Amidation Using Electrophilic Ru(II)-Complexes

“…Signals for the dissolved H2 and CO2 were observed in the 1 H and 13 C NMR spectra, respectively (Figure S1). A peak at 59.3 ppm in the 31 Although it is known that formate could bind better than formic acid, previous reports also suggested the proposed formic acid bound metal complexes as intermediates. (*) as a very likely precursor for complex 2.…”

Mechanistic Insights into Formic Acid Dehydrogenation and Carbon dioxide Amidation Using Electrophilic Ru(II)-Complexes

“…Signals for the dissolved H2 and CO2 were observed in the 1 H and 13 C NMR spectra, respectively (Figure S1). A peak at 59.3 ppm in the 31 Although it is known that formate could bind better than formic acid, previous reports also suggested the proposed formic acid bound metal complexes as intermediates. (*) as a very likely precursor for complex 2.…”