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A mixture of Pd(OAc)(2) and TBA(4)[γ-SiW(10)O(34)(H(2)O)(2)] (TBA-SiW10, TBA = [(n-C(4)H(9))(4)N](+)) showed high catalytic activities for hydration of various kinds of structurally diverse nitriles including aromatic, aliphatic, heteroaromatic, and double bond-containing ones. For hydration of 3-cyanopyridine, the turnover frequency was 860 h(-1), and the turnover number reached up to 670. A dipalladium-substituted γ-Keggin silicodecatungstate, [γ-H(2)SiW(10)O(36)Pd(2)(OAc)(2)](4-) (I), was successfully synthesized by the reaction of [γ-SiW(10)O(34)(H(2)O)(2)](4-) with Pd(OAc)(2) in a mixed solvent of acetone and water. The crystal structure of I was a monomeric, dipalladium-substituted, γ-Keggin silicodecatungstate with bidentate acetate ligands. Compound I showed similar activities and selectivities to those of a simple mixture of Pd(OAc)(2) and TBA-SiW10. The kinetic, mechanistic, and density functional theory calculation studies show that the dipalladium site plays an important role in the present hydration, and the nucleophilic attack of a hydroxide or water to the nitrile carbon atom is included in the rate-determining step.

A single crystal of (NBu4)4 [γ-SiV2W10O39] (I) is prepared from (NBu4)4 [γ-H2SiV2W10O40] (II) with excess PhNCO in 1,2-dichloroethane under Ar at room temperature for 2 d (58% yield).

Under aqueous conditions dimethylamine, piperidine, and triethylamine catalyzed the ring-transformation reaction of triaryl-2H-furo[3,2-b]pyrrole-2,6(6aH)-diones (1), giving benzoylhydroxy-1-pyrrolines 2, which afforded benzoylpyrroles 3 upon acid-catalyzed dehydration. The lactone-ring-opened amides 6 were obtained in the reaction of 1 with methylamine, pyrrolidine, piperidine, and perhydroazepine at room temperature in ethanol. Pyrrolidine and piperidine produced pyrrolecarboxamides 7 when the reaction was carried out in aqueous ethanol under reflux. Amides 6 afforded 7 upon treatment with the amines under the above-mentioned conditions.

Newly synthesized 9-membered diallylic organosulfur cycles have proven to possess planar chirality originating from the rigidity of their medium-sized cyclic structure. The oxidation state of the s...

A novel dinuclear zirconium sandwich-type silicotungstate cluster of [(γ-SiW10O36)2Zr2(μ-OH)2]10- (1) was synthesized by the reaction of a divacant lacunary γ-Keggin silicotungstate [γ-SiW10O36]8- with ZrOCl2·8H2O. The anion consisted of two [γ-SiW10O36]8- units sandwiching a diamond Zr2(μ-OH)2 core, and each zirconium atom in 1 was six-coordinated to two μ-OH ligands and four oxygen atoms of two [γ-SiW10O36]8- units. The Zr2(μ-OH)2 core in 1 reacted with methanol to give the corresponding monomethoxo derivative [(γ-SiW10O36)2Zr2(μ-OH)(μ-OCH3)]10- (2).

Complexation of Keggin-type polyoxometalates (POMs), [α-PW12O40]3- (PW), [α-SiW12O40]4- (SiW), and [γ-SiV2W10O38(OH)2]4- (SiVWH) with cationic transition-metal complexes having a triazacyclononane ligand, [M(tacn)2]n+ (M−tacn; M = CoIII and NiII; tacn = 1,4,7-triazacyclononane), yields fine particles of inorganic−organic composites. The strong electrostatic interaction between the highly negatively charged POMs and the +2- or +3-charged [M(tacn)2]n+ as well as the hydrophobicity of [M(tacn)2]n+ results in the formation of the water-insoluble binary composites. The crystal structure of the 1:1 (=the molar ratio of POM to M−tacn) composite [Co(tacn)2][α-PW12O40]·2H2O (1·H2O) shows the close packing of PW and Co−tacn in the crystal lattice. The guest sorption properties of the corresponding anhydrous compound 1 show that the amounts of hydrophobic molecules sorbed are comparable to that of water. The reaction of SiVWH with Co−tacn yields fine particles of [Co(tacn)2]2[γ-SiV2W10O40]·6H2O (2·H2O), and the mola...

Two novel porous germanates, [Ge 5 O 1 0 ](H 2 O) (1) and [Ge 1 0 O 2 0 OH] [(CH 3 ) 4 N] (2), are synthesized by a hydrothermal method using TMA (tetramethylammonium), and characterized by X-ray crystallography, showing that a novel type of .3 membered rings (two octahedral GeO 6 and one tetrahedral GeO 4 ) exists in 1, and the OH- anions are located in the center of double 4-membered rings in 2.