A novel reversible photochromic nanocomposite film based on a hybrid inorganic-organic matrix in which heteropolyacid H4SiW12O40 （SiWA） was entrapped in Si-O-Ti network was prepared. Structure, photochromic behavior...A novel reversible photochromic nanocomposite film based on a hybrid inorganic-organic matrix in which heteropolyacid H4SiW12O40 （SiWA） was entrapped in Si-O-Ti network was prepared. Structure, photochromic behaviors and mechanism of the film were investigated by means of infrared spectroscopy （IR）, ultraviolet-visible （UV-Vis） absorption spectra and electron spin resonance （ESR）. The results showed that heteropolyanion i.e. SiW12O^4- 40 （SiW12）, maintained a Keggin structure in the film and there was a strong interaction between anion SiW12 and cation R-NH^＋3 （R=link of hybrid composite）. The photochromic properties of the composite film originated from reversible charge transfer between the anions and cations. Under UV irradiation, the anion would be reduced via one-electron step with simultaneous oxidation of the cation, accompanied by a color change from colorless to blue. Bleaching could occur when the film was in contact with ambient air or 02 in the dark.展开更多
Tris, di-( organotitanium) substituted tungstosilicates α,β - (CpTi)3(SiW9037)17– and γ-[(CpTi)2(SiW10O38)] 6– were prepared by the reaction of C2TiC12 (Cp= η-C5H5) with a,β-SiW9 O9/34(noted α,β Siv9,), γ-Si...Tris, di-( organotitanium) substituted tungstosilicates α,β - (CpTi)3(SiW9037)17– and γ-[(CpTi)2(SiW10O38)] 6– were prepared by the reaction of C2TiC12 (Cp= η-C5H5) with a,β-SiW9 O9/34(noted α,β Siv9,), γ-SiWO8/36 (noted γ-SiW10) The products were characterized by means of elemental analysis, IR, 1H NMR, 183W NMR and polarography. 183W NMR spectra of the complexes support the stoichiometry of the new heteropolyanions and the probable retention of the A-XW9 or γ-SiWlO units. And the organotitanium substituted compounds showed promising in vitro antitumor activity in two of human tumor cell lines.展开更多
The present paper covers seven rare earth-containing tungstosilicate heteropoly complexes LnHSiW_(12)O_(40)·xH_2O with Keggin structure(Ln=La,Ce,Pr,Nd,Sm,Eu and Gd)snythesized by double decomposition reaction.The...The present paper covers seven rare earth-containing tungstosilicate heteropoly complexes LnHSiW_(12)O_(40)·xH_2O with Keggin structure(Ln=La,Ce,Pr,Nd,Sm,Eu and Gd)snythesized by double decomposition reaction.The synthesized heteropoly complexes were characterized by ICP,^(29)Si-NMR,XPS, XRD,IR,UV,polarogram,CV and TG-DTA.The relationship between the structure of the synthesized heteropoly complexes and their properties is discussed.展开更多
文摘A novel reversible photochromic nanocomposite film based on a hybrid inorganic-organic matrix in which heteropolyacid H4SiW12O40 （SiWA） was entrapped in Si-O-Ti network was prepared. Structure, photochromic behaviors and mechanism of the film were investigated by means of infrared spectroscopy （IR）, ultraviolet-visible （UV-Vis） absorption spectra and electron spin resonance （ESR）. The results showed that heteropolyanion i.e. SiW12O^4- 40 （SiW12）, maintained a Keggin structure in the film and there was a strong interaction between anion SiW12 and cation R-NH^＋3 （R=link of hybrid composite）. The photochromic properties of the composite film originated from reversible charge transfer between the anions and cations. Under UV irradiation, the anion would be reduced via one-electron step with simultaneous oxidation of the cation, accompanied by a color change from colorless to blue. Bleaching could occur when the film was in contact with ambient air or 02 in the dark.
文摘Tris, di-( organotitanium) substituted tungstosilicates α,β - (CpTi)3(SiW9037)17– and γ-[(CpTi)2(SiW10O38)] 6– were prepared by the reaction of C2TiC12 (Cp= η-C5H5) with a,β-SiW9 O9/34(noted α,β Siv9,), γ-SiWO8/36 (noted γ-SiW10) The products were characterized by means of elemental analysis, IR, 1H NMR, 183W NMR and polarography. 183W NMR spectra of the complexes support the stoichiometry of the new heteropolyanions and the probable retention of the A-XW9 or γ-SiWlO units. And the organotitanium substituted compounds showed promising in vitro antitumor activity in two of human tumor cell lines.
文摘The present paper covers seven rare earth-containing tungstosilicate heteropoly complexes LnHSiW_(12)O_(40)·xH_2O with Keggin structure(Ln=La,Ce,Pr,Nd,Sm,Eu and Gd)snythesized by double decomposition reaction.The synthesized heteropoly complexes were characterized by ICP,^(29)Si-NMR,XPS, XRD,IR,UV,polarogram,CV and TG-DTA.The relationship between the structure of the synthesized heteropoly complexes and their properties is discussed.
