Hydroxyl bond activation of formic acid by Metal-ligand cooperation of new designed aluminum ligated pincer fullerenes

Abstract

• New designed aluminum ligated NNN pincer fullerene. • Aluminum-ligand cooperation ►►OH bond cleavage HCOOH. • H 2 elimination ►►protonation of imine carbon atom. • The aluminum complex with three HCOO►► active catalyst. • Catalytic cycle►► β-hydride elimination to dissociate CO 2 . The two parts of the formic acid dehydrogenation reaction including catalyst activation and catalytic cycle with a new designed aluminum ligated NNN pincer fullerene as catalyst in which Al(III)–bis(imino)pyridyl pincer are located on the (6, 6) ring fusion bond of C 60 fullerene was investigated with density functional calculations. Aluminum-ligand cooperation enables O H bond cleavage of formic acid in the HCOOH-assisted H 2 elimination pathway with protonation of imine carbon atom. The aluminum complex with three HCOO – units (complex 8 ) forms the active catalyst of HCOOH dehydrogenation. The existences of hydrogen bonds in the studied molecules were confirmed by NBO and AIM analyses. In the catalytic cycle, β-hydride elimination from 8 to dissociate CO 2 and formation of Al–H complex promote HCOOH dehydrogenation to generate H 2 . The β-hydride elimination is the rate-determining step with an overall barrier of +17.8 kcalmol −1 . The effect of fullerene cage on the catalytic cycle of HCOOH dehydrogenation is explored by elimination of fullerene cage from the Al(III)– bis(imino)pyridyl pincer fullerene.