|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 2000 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1999 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1998 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Several novel results in this research were obtained :
1. The Cp^*Rh^<2+> complex (Cp^* = C_5Me_5) supported on the V_3 surface (B-site) of 1, 4, 9-tri-vanadium(V)-substituted Keggin polyoxotungstate [1, 4, 9-PW_9V_3O_<40>]^<6-> was synthesized. The product also contained [Cp^*Rh(DMSO)_3]^<2+> as counterion.
2.Tri-Ti^<IV>-and di-Ti^<IV>-substituted Keggin polyoxotungstate were isolated as potassium salts and their X-ray crystal structures determined. Ultracentrifugation molecular weight (MW) measurements were also performed in aqueous solution. The two Ti^<IV>-substituted compounds in the solid state were dimeric, Ti-O-Ti anhydride forms of two α-Keggin [1, 2, 3-PW_9Ti_3O_<40>]^<9-> units and of two novel α-Keggin [1, 2-PW_<10>Ti_2O_<40>]^<7-> units, respectively. Solution MW measurements showed that the former was a dimer in pH7.0 aqueous solution, whereas the latter was a monomer in pH 7.8 aqueous solution.
3. The supported-polyoxotungstates formed between tri-metal-substituted Dawson polyoxotungstate [P_2W_<15>M_3O_<62>]^<9-> (M = Nb^V, V^V) and organometallic groups ((cod)Pt^<2+> and Cp^*Rh^<2+>) were synthesized, and the effects polyoxoanion-support (Nb vs. V) and organometallic species ((cod)Pt^<2+> vs. Cp^*Rh^<2+>) were elucidated.
4. Oxidation products of toluene and nitrobenzene with 30% aqueous H_2O_2 catalyzed by several vanadium(V)-substituted Keggin and Dawson polyoxometalates were carefully analyzed by GC/MS measurements. Polyoxometalates which promote the reaction via an ionic mechanism and via a radical mechanism were classified.