A Lewis acid catalytic core sandwiched by inorganic polyoxoanion caps: selective H2O2-based oxidations with [Al(III)4(H2O)10(β-XW9O33H)2](6-) (X = As(III), Sb(III)).

The Al(III)-containing polyanions [Al(III)4(H2O)10(β-XW9O33H)2](4-) with X = As(III) (1) and Sb(III) (2) feature four aluminum(III) centers sandwiched by two trivacant (β-XW9O33) Keggin units, and trigger peroxide catalysis as well as substrate coordination via multiple Lewis acid site interactions.

Alpha and beta isomers of tetrahafnium(IV) containing decatungstosilicates, [Hf4(OH)6(CH3COO)2(x-SiW10O37)2]12- (x = α, β).

The two dimeric, Hf-containing tungstosilicates [Hf(4)(OH)(6)(CH(3)COO)(2)(α-SiW(10)O(37))(2)](12-) (1) and [Hf(4)(OH)(6)(CH(3)COO)(2)(β-SiW(10)O(37))(2)](12-) (2) have been synthesized by reacting HfCl(4) with [γ-SiW(10)O(36)](8-) in potassium acetate solutions at pH = 3.6 and 4.8, respectively.

Large cation-anion materials based on trinuclear ruthenium(III) salts of Keggin and Wells-Dawson anions having water-filled channels.

Reaction of the trinuclear ruthenium(III) cation [Ru(3)O(OOCCH(3))(6)(CH(3)OH)(3)](+) with the Keggin-type [alpha-GeW(11)O(39)](8-), [alpha-SiW(11)O(39)](8-), and [alpha-SiMo(12)O(40)](4-) and the Wells-Dawson-type [alpha-P(2)W(18)O(62)](6-) polyanions in an aqueous, acidic medium resulted in plenary polyoxometalate-based materials K(2)Na[Ru(3)O(OOCCH(3))(6)(H(2)O)(3)][alpha-GeW(12)O(40)].10H(2)O (1), K(3)[Ru(3)O(OOCCH(3))(6)(H(2)O)(3)][alpha-SiW(12)O(40)].18H(2)O (2), K(3)[Ru(3)O(OOCCH(3))(6)(H(2)O)(3)][alpha-SiMo(12)O(40)].

Solvent-free aerobic oxidation of n-alkane by iron(III)-substituted polyoxotungstates immobilized on SBA-15.

The tetrairon(III)-substituted polytungstates [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](n-) (n = 6, X = As(III), Sb(III); n = 4, X = Se(IV), Te(IV)) were immobilized on (3-aminopropyl)triethoxysilane-modified SBA-15 and showed an excellent catalytic performance for solvent-free aerobic oxidation of long-chain n-alkanes using air as the oxidant under ambient conditions through a classical free-radical chain autoxidation mechanism.

Determination of geometric orientation of adsorbed cinchonidine on Pt and Fe and quiphos on Pt nanoclusters via DRIFTS.

Platinum nanoclusters modified with cinchonidine have been employed as 'quasi-homogeneous' catalysts for the hydrogenation of ethyl pyruvate and have demonstrated exceptional activities while the ee's of these systems are currently inferior to the traditional Pt/Al2O3 heterogeneous system. For the bulk systems it has been shown that the orientation of the modifier on the metal surface is a critical parameter influencing catalytically induced enantioselectivity. It has been speculated that the lower observed ee's for the nanocluster systems are a result of the modifier assuming an orientation unfavorable for inducing enantioselectivity due to the lack of large numbers of planar metal atoms.

In situ approaches to establish colloidal growth kinetics.

A technique based on the back scattering phenomenon of dynamic light scattering has been employed to monitor the kinetics of gold and platinum metal nanoparticle growth and silver nanoparticle oxidation as well as in the determination of particle sizes ranging from 1 to 200 nm in diameter. The systems were chosen to examine the applicability of dynamic light scattering to nanoresearch over a broad range of sizes as well as both metallic and nonmetallic systems. The advantages of this instrumentation over traditional instruments such as X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) have been highlighted.