Ee. Platero et Mp. Mentruit, INTERACTION OF GROUP-6 METAL-CARBONYLS WITH SULFATED ZIRCONIUM DIOXIDE - IR STUDIES, Inorganic chemistry, 33(7), 1994, pp. 1506-1509
The interaction of Cr(CO)6, MO(CO)6, and W(CO)6, with dehydroxylated a
ctive zirconia (prepared by thermolysis of a zirconium sulfate) has be
en studied by in situ IR spectroscopy. Adsorption of the three metal c
arbonyls takes place via O-bonding between a CO ligand and Lewis acid
sites on the zirconia surface. Two kinds of these sites (with differen
t Lewis acid strength) have been identified using CO as a spectroscopi
c probe. Formation of surface adducts between the zirconia support and
the metal carbonyls was found to labilize CO ligands. Reversible deca
rbonylation of the adsorbed metal carbonyls was observed when pumping
at room temperature. Subsequent admission of CO into the IR cell regen
erates the hexacarbonyl surface adducts. The stability of these adduct
s (toward decarbonylation) was found to follow the order W(CO)6 > Cr(C
O)6 > MO(CO)6.