It is now IS years since the first patents in polymer supported metal
complex catalysts were taken out. In the early days ion-exchange resins
were used to support ionic metal complexes. Soon covalent links were
developed, and after an initially slow start there was a period of
explosive growth in the mid to late 1970s during which virtually every
homogeneous metal complex catalyst ever reported was also studied bound
to a support. Both polymers and inorganic oxides were studied as
supports, although the great preponderance of workers studied polymeric
supports, and of these polystyrene was by far the commonest used. This
period served to show that by very careful design polymer-supported
metal complex catalysts could have specific advantages over homogeneous
metal complex catalysts. However the subject was a complicated one.
Merely immobilising a successful metal complex catalyst to a
functionalised support rarely yielded other than an inferior version of
the catalyst. Amongst the many discouraging results of the 1970s, there
were more than enough results that were sufficiently encouraging to
demonstrate that, by careful design, supported metal complex catalysts
could be prepared in which both the metal complex and the support
combined together to produce an active catalyst which, due to the
combination of support and complex, had advantages of activity,
selectivity and specificity not found in homogeneous catalysts. Thus a
new generation of catalysts was being developed.