Layered Tungsten Oxide-Based Organic−Inorganic Hybrid Materials:  An Infrared and Raman Study

Abstract

Tungsten oxide-organic layered hybrid materials have been studied by infrared and Raman spectroscopy and demonstrate a difference in bonding nature as the length of the interlayer organic "spacer" molecule is increased. Ethylenediamine-tungsten oxide clearly displays a lack of terminal -NH3(+) ammonium groups which appear in hybrids with longer organic molecules, thus indicating that the longer chains are bound by electrostatic interactions as well as or in place of the hydrogen bonding that must be present in the shorter chain ethylenediamine hybrids. The presence of organic molecules between the tungsten oxide layers, compared with the layered tungstic acid H2WO4, shows a decrease in the apical W=O bond strength, as might be expected from the aforementioned electrostatic interaction.

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…Some groups have investigated the intercalation of organic molecules such as diaminoalkane, phenethylamine, pyridine and poly(ethylene glycol) in the interlayer space of both structures, WO 3 and MoO 3 . [220][221][222][223] A nice example is the preparation of tungsten oxide layers intercalated with acetic acid and hexamethylenetetramine (HMT) molecules with a 3D flowerlike morphology. [224] The most important result of the work is the good reversibility (as high as 98.4%, which is much higher than conventional WO 3 materials) and the good coloration response expanded to the visible-light region, which is a critical challenge for practical applications using solar energy and other visible laser sources.…”

Layered tungsten oxide-based hybrid materials incorporating transition metal ions

“…The major organic modes are illustrated: N-H stretching 3240-3340 cm À1 , C-H stretching 2840-2940 cm À1 , NH 2 bending 1570 cm À1 . It is clear from these spectra that unlike the tungsten oxide/organic hybrids, in which the organic amines are protonated [10], the organic molecules of the manganese tungstate hybrids are neutral. This is evidenced by the clarity of the N-H stretching lines, the presence of the simple NH 2 bending mode, and the absence of broad features at $2100 cm À1 (characteristic of R-NH þ 3 Á Á Á À O-W bonding).…”

“…Similarly, the notation ''W-DAn'' identifies hybrid materials made without additional transition metals in our previous investigations [9][10][11].…”

“…When hydrated, it forms layers of corner-shared WO 6 octahedra separated by water molecules [8]. Recent work by our group has been to develop this structure to include organic molecules (in particular, primary amines) in place of the water molecules [9][10][11].…”

Tungsten oxide-Au nanosized film composites for glucose oxidation and sensing in neutral medium

“…32 The spectrum shows three broad features in the 100-300 cm 33,34 The Raman bands at 275 cm -1 and 430-440 cm -1 correspond to the deformation vibrations of (O-W-O) bonds and the band at 800 cm -1 corresponds to the stretching vibrations of W-O bonds. 35,36 It should be noted that XRD (not shown) did not show any peak related to metallic W.…”