Synthesis, Structure and Catalytic Activity of ... - Jacobs University

Chapter I
Introduction
1.1 A brief history
The history of the field of Polyoxometalates (POMs) dates back to the first
third of the nineteenth century, when Berzelius first reported the formation
of Ammonium 12-molybdophosphate (NH4)3[PMo12O40] in 1826. 1,2
There have been attempts in the next hundred years to understand this new
class of compounds. Miolati in 1908 and Rosenheim later on, applied the ionic
coordination theory, which was criticized by Pauling in 1929. The latter
suggested instead, a structure formed by MoO6 octahedra encapsulating a
PO4 3- unit. Pauling made some progress in the right direction, but it was
until 1933, that Keggin provided an explicit description of the structure that
was named after him. Other types of structures were later reported in
literature, the Anderson-Evans in 1948 and the Wells-Dawson in 1953 for
instance. 1,2,3
Nevertheless, it was only in the past few decades that the real burst in the
POMs field began, owing to the development of the modern experimental
techniques (e.g NMR and single crystal XRD) and the promising potential
applications, namely catalysis, that became apparent at the time.
Most of the pioneering systematic studies on the catalytic use of POMs were
carried out in Russia (Matveev and coworkers) and Japan (Izumi, Misono,
Ono, Otake, Yoneda and co-workers). It was actually in Japan in 1972, that a
heteropolyacid H4[SiW12O40] was industrially employed for the first time, as a
homogeneous catalyst for the hydration of propene to 2-propanol. 2,4,5,6
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