Homogeneous and Supported Niobium Catalysts as Lewis Acid and Radical Catalysts

Tikkanen, Wayne

Cal State L.A. University Auxiliary Svcs, Inc.

关键词: Aldehydes;    Drying;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Catalysts;    Radicals;   

DOI  :  10.2172/922133
RP-ID  :  None
RP-ID  :  FG26-05NT42493
RP-ID  :  922133

美国|英语

来源: UNT Digital Library

【 摘 要 】

The synthesis of tetrachlorotetraphenylcyclopentadienyl group 5 metal complexes has been accomplished through two routes, one a salt metathesis with lithiumtetraphenylcyclopentadiende and the other, reaction with trimethyltintetraphenylcyclopentadiene. The reactants and products have been characterized by {sup 1}H and {sup 13}C({sup 1}H) NMR spectroscopy. The niobium complex promotes the silylcyanation of butyraldehyde. The grafting of metal complexes to silica gel surfaces has been accomplished using tetrakisdimethylamidozirconium as the metal precursor. The most homogeneous binding as determined by CP-MAS {sup 13}C NMR and infrared spectroscopy was obtained with drying at 500 C at 3 mtorr vacuum. The remaining amido groups can be replaced by reaction with alcohols to generate surface bound metal alkoxides. These bound catalysts promote silylcyanation of aryl aldehydes and can be reused three times with no loss of activity.