RESUMEN
A trialuminum-substituted ß-isomer Keggin-type tungstoaluminate was synthesized and characterized, in which the pure metal-oxygen cluster [AlW8.5Al0.5{Al(OH2)}3(OH)3O34](6.5-) consists of three kinds of aluminum sites: the central Al(1), the doped Al(5), and the substituted Al(2) and Al(3) centers.
RESUMEN
Polyanionic cluster [ß-As8V14O42(H2O)](4-) is well embedded in a large porous eight-membered cationic ring of the copper ligand, giving a stable host-guest supramolecular system. The assembly exhibits an efficient heterogeneous catalytic performance for the reduction of Cr(VI) using formic acid at ambient temperature.
RESUMEN
A novel aluminum-containing, bimolybdenum-capped Keggin-type polyoxomolybate cluster of the {AlMo12O40(MoO2)2} anion has been synthesized and characterized. This is the first experimentally determined Keggin-type {AlMo12O40} polyoxoanion. The polyoxometalate crystal exhibits high selectivity toward the heterogeneous catalytic oxidation of cyclohexanol to cyclohexanone.
Asunto(s)
Molibdeno/química , Compuestos Organometálicos/química , Oxígeno/química , Electroquímica , Modelos Moleculares , Conformación MolecularRESUMEN
In the title compound, [Cu(NO(3))(2)(C(8)H(9)N(3))(2)], the Cu(II) atom, lying on an inversion center, has a distorted octa-hedral coordination environment defined by four N atoms from two chelating 2-amino-methyl-1H-benzimidazole ligands and two O atoms from two monodentate nitrate anions. In the crystal, N-Hâ¯O hydrogen bonds link the complex mol-ecules into a three-dimensional network. An intra-molecular N-Hâ¯O hydrogen bond is also observed.
RESUMEN
Two novel sandwich-type polyanions containing hexagonal {V=O}(6) group (H(2)tpy)(Hbpe)(3)H[(VO)(6)(SbW(9)O(33))(2)]·2H(2)O (1) and (H(2)tcy)(6)(Hbpp)(6)H(4)[VW(12)O(40)][(VO)(6)(SbW(9)O(33))(2)](3)·30H(2)O (2) (tpy = 4-(2,3,4-tri(pyridin-4-yl)butyl)pyridine, bpe = 1,2-(4-pyridyl)ethene, tcy = 1,2,4,5-tetra(pyridin-4-yl)cyclohexanol, bpp = 1,3-bis-(4-pyridyl)propane), were reported. Both compounds are built upon the complex hydrogen bonding networks of C-H···O and N-H···O occurred among inorganic anions and organic cations. Unusual in situ organic reactions involving C-C coupling are also observed in 1 and 2 regardless of the rigid bpe or flexible bpp. Compound 2 represents a rare case in which nano-sized α-Keggin [VW(12)O(40)](4-) and sandwich-type [(VO)(6)(SbW(9)O(33))(2)](6-) anionic clusters are present in a common crystal framework.
RESUMEN
In the present paper, microwave digestion technique was used to determine Ca, Zn, Cu, Mg and Fe in rat liver by flame atomic absorption spectrometry (FAAS). The effect of microwave digestion condition on the analysis results was examined and the best analysis condition of FAAS was selected. Compared to traditional wet methods, the experimental result showed that the method is rapid, sample digestion is complete, the blank value is low, and the measurement result is satisfactory. Applied to the determination of trace elements in rat liver, the method proved to be selective with satisfactory recovery of 96%-103% andrelative standard deviation of 1.0%-2.6%.