Photomechanical photochromism in a cetyltrimethylammonium isopolytungstate

Abstract

The photochromic properties of a hybrid compound comprised of the surfactant cation cetyltrimethylammonium [(C16H33)N(CH3)3]+ and the isopolytungstate anion [H2W12O40]6− is investigated.

Trapping a [W10O32]6− Decatungstate Anion in an Ag44 Nanowheel

“…In compound 1 , one decatungstate anion is symmetrically wrapped in the Ag 44 shell through Ag−O bonds, as shown in Figure 1 and Figure 2. The W VI 4f 7/2 , W VI 4f 5/2 , W V 4f 7/2 , W V 4f 5/2 signals together with a clear W V 5p 3/2 signals are observed and the ratio of the W VI and W V atoms is 8: 2 in the X‐ray photoelectron spectroscopy (XPS) analysis (Figure 4), [32] which effectively proves that the central decatungstate anion is the [W 10 O 32 ] 6− [33–35] . Herein, [W 10 O 32 ] 6− can be regarded as the formation of ten tungsten oxide octahedrons WO 6 connected by corner‐sharing and edge‐sharing modes, or it can be regarded as the two W 5 O 18 units aggregated by the corner‐sharing mode (Figure 2b).…”

“…The W VI 4f 7/2 , W VI 4f 5/2 , W V 4f 7/2 , W V 4f 5/2 signals together with a clear W V 5p 3/2 signals are observed and the ratio of the W VI and W V atoms is 8: 2 in the X-ray photoelectron spectroscopy (XPS) analysis (Figure 4), [32] which effectively proves that the central decatungstate anion is the [W 10 O 32 ] 6À . [33][34][35] Herein, [W 10 O 32 ] 6À can be regarded as the formation of ten tungsten oxide octahedrons WO 6 connected by corner-sharing and edge-sharing modes, or it can be regarded as the two W 5 O 18 units aggregated by the cornersharing mode (Figure 2b). And regardless of the external organic ligand structure, larger anion sizes usually result in larger nuclear silver clusters.…”

X‐ray‐induced reduction of a surfactant/polyoxotungstate hybrid compound

“…The sample had been subjected to several survey scans prior to the first displayed measurement. These survey scans had shown that carbon was present in 2 environments (most likely in the alkane chains, as well as bound to the cationic head group) and oxygen in 2 environments (the Keggin ion as well as in adsorbed H 2 O) . W4f 5/2 and W4f 7/2 spin‐orbit doublets of the W 6+ and W 5+ states appear at 39.4 and 37.2, and 37.6 and 35.4 eV respectively.…”

“…Many redox‐active, photoresponsive oxide‐containing organic‐inorganic hybrids have similarly confined oxide phases surrounded by organic species, such as surfactant‐encapsulated or polymer‐coated nanoparticles, nanowires, and quantum dots, and therefore would also be highly susceptible to soft X‐ray‐induced photoreduction . In fact, we recently observed that more transmissive hard X‐rays (18 keV) from a synchrotron source induced disorder and colouring of the POMs in CTA‐W 12 , likely through decomposition of the structure supporting CTA + amphiphiles by X‐ray‐induced photoredox processes between the inorganic and organic components . Efforts should be made to minimise X‐ray‐induced damage in samples containing photoreducible metal cations, such as reducing total incident X‐ray flux, or cryogenic cooling of the sample .…”

Synthesis and properties of low‐cost, photochromic transparent hydrogel based on ethaline‐assisted binary tungsten oxide‐molybdenum oxide nanocomposite for optical memory applications

“…The sample was placed under the light at a distance of 10 cm between the sample and the light, after which the absorption was measured using a UV-Vis-NIR spectrometer. From 43,65,66 hence leading to the enhanced photochromic response with the color changing from transparent to deep blue-black (Figure 8D) at 300 s irradiation exposure. Since different amount of water were used as cosolvent in the preparation of the binary metal oxide nanocomposites, the effect could also be observed on the photochromic enhancement of the hydrogel (Figure 8E), 67 with HZ 0.1 exhibiting intense coloration (blue-black) response at 60 s irradiation exposure, compared to previously reported coloration whose changes were either light green or blue.…”