Reactivity of a Ruthenium-Carbonyl Complex in the Methanol Dehydrogenation Reaction

Finding new catalysts for the release of molecular hydrogen from methanol is of high relevance in the context of the devel- opment of sustainable energy carriers. Herein, we report that the ruthenium complex Ru(salbinapht)(CO)(P i-Pr 3 ) {salbinapht = 2-[({2’-[(2-hydroxybenzyl)amino]-[1,1 ’ -binaphthalen]-2-yl}imino)- methyl]phenolato} (2) catalyzes the methanol dehydrogenation reaction in the presence of base and water to yield H 2 , for- mate, and carbonate. Dihydrogen is the only gas detected and a turnover frequency up to 55 h 1 at 82 8C is reached. Complex 2 bears a carbonyl ligand that is derived from methanol, as is demonstrated by labeling experiments. The carbony l ligand can be treated with base to form formate (HCOO ) and hydro- gen. The nature of the active species is further shown not to contain a CO ligand but likely still possesses a salen-derived ligand. During catalysis, formation of Ru(CO) 2 (H) 2 (P-iPr 3 ) 2 is oc- casionally observed, which is also an active methanol dehydro- genation catalys