The metal complex effect on metal clusters in liquid medium

The metal complex effect on platinum clusters has been studied in the homogeneous liquid-phase hydrogenation of cinnamaldehyde (GAL) at 303 K and 4.0 MPa. The addition of metal complexes to the polymer-stabilized colloidal platinum cluster can considerably modulate both the activity and selectivity of the catalyst. When the neat platinum cluster was served as the catalyst, only moderate conversion (65.5%) of CAL and low selectivity (17.7%) to cinnamyl alcohol (COL) were obtained. However, the conversion was promoted to 78.0% and higher selectivity (75.0%) to COL was obtained, when employing Na3FeF6 as the modifier; otherwise by introducing Ni(bpy)(3)Cl-2 to the catalytic system, the conversion was remarkably enhanced to 82.1% and surprisingly the main product was not COL but hydrocinnamaldehyde (HCAL) with the selectivity of 97.3%. (C) 1997 Elsevier Science B.V.