A well-defined Pd hybrid material for the Z-selective semihydrogenation of alkynes characterized at the molecular level by DNP SENS

Direct evidence of the conformation of a Pd–N heterocyclic carbene (NHC) moiety imbedded in a hybrid material and of the Pd–NHC bond were obtained by dynamic nuclear polarization surface-enhanced NMR spectroscopy (DNP SENS) at natural abundance in short experimental times (hours). Overall, this silica-based hybrid material containing well-defined Pd–NHC sites in a uniform environment displays high activity and selectivity in the semihydrogenation of alkynes into Z-alkenes.