  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 alkane 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.
