An active, stable and recyclable Ru(II) tetraphosphine-based catalytic system for hydrogen production by selective formic acid dehydrogenation

Well-defined and in situ made RuIJII) complexes of the linear tetraphosphine ligand meso-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane (tetraphos-1, P4) proved to be effective catalysts for selectiveformic acid dehydrogenation with good yields and TONs in the presence of an added amine, both underbatch and continuous feed experimental conditions. The mechanism was studied by solution NMR andDFT calculations, highlighting the role of the trans-dihydrido complex [Ru(H)2(meso-P4)] as the active speciesin catalysis.