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91.
Carlos Camacho-Camacho Maria E. Castillo-Ramos Aurora Vásquez-Badillo Angelina Flores-Parra Rosalinda Contreras 《Journal of organometallic chemistry》2010,695(6):833-9863
The syntheses of [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]diphenyltin (1) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]dichloro-phenyl-stannate (2) by template reactions using 3,5-di-tert-butylcatechol, aqueous ammonia and SnPh2Cl2 are reported. We also report the syntheses of compounds 2, [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]trichloro-stannate (4), [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)methylamine]chloro-methyltin (5), and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)-n-butylamine]n-butyl-chlorotin (6) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]n-butyl-dichloro-stannate (7), performed by transmetallation reactions of the octahedral zinc coordination compound Zn[3,5-di-tert-butyl-1,2-quinone-(3,5-di-tert-butyl-2-hydroxy-1-phenyl)imine]2 (3) with SnPhCl3 or SnPh2Cl2, SnCl4, SnMe2Cl2, Sn(nBu)2Cl2 and Sn(nBu)Cl3, respectively. The X-ray diffraction structures of compounds 1, 2, 4 and 6 are reported. The transmetallation reactions with Sn(alkyl)2Cl2 afforded pentacoordinated tin compounds, where an alkyl group migrated from tin to nitrogen, while similar reactions with Sn-Ph compounds did not present any phenyl group migration. 相似文献
92.
Majid Moghadam Shahram TangestaninejadValiollah Mirkhani Iraj Mohammadpoor-BaltorkMostafa Khajehzadeh Farshid KosariMehdi Araghi 《Polyhedron》2010
High-valent tin(IV)octabromotetraphenylporphyrinato trifluoromethanesulfonate, [SnIV(Br8TPP)(OTf)2], was used for selective methoxymethylation of alcohols and phenols with formaldehyde dimethyl acetal (FDMA) at room temperature. Different primary, secondary and tertiary alcohols as well as phenols were converted to their corresponding methoxymethyl ethers with FMDA in the presence of an electron deficient tin(IV) porphyrin. The catalyst was reused several times without significant loss of its activity. 相似文献
93.
Jing Jin Zhiping Zhang Jincheng Wang Peipei Qi Jiping Chen 《Journal of separation science》2010,33(12):1836-1841
Magnesium oxide microspheres were developed as a novel SPE sorbent for the determination of benzo[a]pyrene (BaP), one of the most potent carcinogenic agents, in environmental water samples. The parameters controlling the extraction efficiency, such as elution volume, flow rate, pH values, and breakthrough volume, were investigated in detail. Considering the facile preparation and satisfying recovery, a corresponding analytical method has been developed to determine the concentration of BaP in real tap water, river water, and seawater. The recoveries for the spiked BaP were excellent (94–101%). 相似文献
94.
Gaelle Kerric Françoise Zammattio Jean-Paul Quintard 《Journal of organometallic chemistry》2010,695(1):103-3321
An insoluble polymer-supported phenyltin reagent was successfully used in Stille cross-coupling reactions with aryl- and heteroaryl-halides. Cross-coupling products were isolated in good to high yields with very low contamination by tin and palladium residues after removal of the residual supported organotin halide. The regeneration and recyclability of the supported phenyltin reagent were also examined and proved to be possible, but required palladium cleaning of the grafted polymer to be efficient along 4 cycles when Pd(PPh3)4 was used as catalyst. 相似文献
95.
The optical properties of a silver-doped phosphate glass have been monitored during thermal processing at several fixed temperatures by in situ optical microspectroscopy. Silver nanoparticle (NP) formation and growth processes were assessed by analysis of surface plasmon resonance spectral features. Nucleation and growth processes were distinguished, which appeared temperature and time dependent. While nucleation was favored at low temperatures, relatively high temperatures promoted NP growth by silver diffusion. Photoluminescence spectra acquired along with optical absorption data indicated a continuous reduction of Ag+-Ag0 pairs concomitant with NP precipitation, suggesting their role as nucleation centers. The work of Ag NP formation and the activation energy for silver diffusion were estimated. 相似文献
96.
Feng JiangHonglie Shen Chao GaoBing Liu Long LinZhou Shen 《Applied Surface Science》2011,257(11):4901-4905
SnS films have been prepared by a novel two-stage process. It involved sputtering of Sn film on glass substrate and sulfurization of the thin metallic tin precursor layers in a vacuum furnace. The X-ray diffraction results showed that the SnS layers had orthorhombic structure and (0 4 0) preferential growth is more and more obvious with the increase of sulfurization time. The SnS film obtained by this work shows high optical absorption efficiency, and the film has a direct optical band gap of about 1.3 eV. The films show p-type conductivity and the resistivity of SnS film decreased obviously under illumination. 相似文献
97.
Rajoshree Bandyopadhyay 《Journal of organometallic chemistry》2010,695(7):1012-10984
The treatment of tin(II) trifluoromethanesulfonate with three differently-sized crown ethers [12]crown-4, [15]crown-5 and [18]crown-6 results in the formation of tin complexes that exhibit dramatically different structural features. The compounds are investigated using experimental techniques and density functional theory calculations. 相似文献
98.
The present study provides the first experimental evidence for the stabilization of tin dopant cations immediately on the surface of an oxide having a tetragonal structure. 119Sn Mössbauer spectra of the dopant, introduced by air annealing into the bulk of anatase microcrystals, showed that it was located, in the tetravalent state, in somewhat distorted octahedral sites of a unique type. On the contrary, the reduced tin species, formed upon subsequent hydrogen annealing the Sn4+-doped samples, are found to occupy different sites being characterized by two sets of the isomer shift δ and quadrupole splitting ΔEQ values (δI = 3.25 mm s−1, ΔEQI = 1.75 mm s−1; and δII = 2.85 mm s−1, ΔEQII = 1.71 mm s−1). Either of them implies both the divalent state of tin atoms and their presence at low-coordination sites that can be assigned to the surface of crystallites. Mössbauer spectra of Sn4+←2+ daughter ions, formed upon contact with air of Sn2+, consist of a symmetrically broadened peak characterized by only slightly different average values of both the isomer shift (<δ> = 0.07 mm s−1) and quadrupole splitting (<ΔEQ> = 0.50 mm s−1), as compared to the δ and ΔEQ values for the bulk-located Sn4+. However, considerable broadening of Sn4+←2+ doublet components (Γ = 0.97 mm s−1) allows one to suggest that these secondary formed ions remain distributed over the non equivalent sites inherited from their Sn2+ precursors. The occurrence of Sn4+←2+ at surface sites is independently proven by XPS measurements that revealed a greater than 10-fold enrichment with tin of 3–5 nm thick surface layers. 相似文献
99.
Kerdock codes (Kerdock, Inform Control 20:182–187, 1972) are a well-known family of non-linear binary codes with good parameters
admitting a linear presentation in terms of codes over the ring (see Nechaev, Diskret Mat 1:123–139, 1989; Hammons et al., IEEE Trans Inform Theory 40:301–319, 1994). These codes have been
generalized in different directions: in Calderbank et al. (Proc Lond Math Soc 75:436–480, 1997) a symplectic construction
of non-linear binary codes with the same parameters of the Kerdock codes has been given. Such codes are not necessarily equivalent.
On the other hand, in Kuzmin and Nechaev (Russ Math Surv 49(5), 1994) the authors give a family of non-linear codes over the
finite field F of q = 2
l
elements, all of them admitting a linear presentation over the Galois Ring R of cardinality q
2 and characteristic 22. The aim of this article is to merge both approaches, obtaining in this way new families of non-linear codes over F that can be presented as linear codes over the Galois Ring R. The construction uses symplectic spreads.
相似文献
100.
The Influencing Mechanism of Acidity on the Oxidation Peak Currents of Uric Acid and Ascorbic Acid at the PACPE by Cyclic Voltammetry
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In this paper, a pre‐anodized carbon paste electrode (PACPE) is fabricated by a simple electrochemical pretreatment method, which can be used for the simultaneous determination of uric acid (UA) and ascorbic acid (AA). The influencing mechanism of the acidity on the size of oxidation peak current (ip,a) of UA and AA is discussed in detail. According to the results, in different pH conditions, the intensity of hydrogen bonding between UA, AA and the surface of PACPE, the degree of reduction reaction at the auxiliary electrode, and the structural configurations of UA and AA with different species in reaction system have evident influence on the size of oxidation peak current. In pH 7.00 phosphate buffer solution, the calibration curves for UA and AA are obtained in the range of 5.0 x 10‐7–5.0 x 10‐5 mol/L and 3.0 x 10‐5–5.0 x 10‐3 mol/L, respectively. The detection limits for UA and AA are found to be 2.0 x 10‐8 mol/L and 1.2 x 10‐6 mol/L, respectively. This proposed method has been successfully applied to determine UA and AA in human urine simultaneously with satisfactory results. 相似文献