Incorporation of PdCl2P2 Complexes in Ni-MOF for Catalyzing Heck Arylation of Functionalized Olefins

Two palladium complexes of a PdCl2P2 type with P = tri(1-piperidinyl)phosphine (Pd-1) and triphenylphosphine (Pd-2) were successfully immobilized on [Ni-8(OH)(4)(OH2)(2)(L)(6)](n) (Ni-MOF) material [L=4,4 '-(benzene-1,4-diyldiethyne-2,1-diyl)bis(1-H-pyrazole)] to form Pd@Ni-MOF composites. The presence of big octahedral cavities in the Ni-MOF structure (2.4 nm) enabled incorporation of PdCl2P2 molecules inside the Ni-MOF, as confirmed by physicochemical measurements and computer simulation. The Pd@Ni-MOF composites catalyzed arylation of estragole by iodobenzene with an efficiency higher than that for the corresponding PdCl2P2 compounds without MOF. Arylation of eugenol by PhB(OH)(2) unexpectedly resulted in the formation of ether as the main product. This was explained by the dominating activity of the Cu@MOF catalyst, formed in situ under the reaction conditions.