Nickel Polymerization Catalysts with Ylide Steering Ligands - Late Transition Metal Polymerization Catalysis - page 19

Fig. 1.4 Temperature dependence of the ylide-Ni catalyst activity in acetylene polymerization.
control over the (unknown) polymer architecture, an application-oriented product
optimization becomes difficult. To make matters even worse, URPAC is unstable
in air and thus, up to now, virtually useless.
Clearly, novel concepts for catalysts, changing the property profile, had to be de-
veloped to overcome these drawbacks.
1.7.1
Catalyst Activity [20]
Bis(ylide)nickel catalysts are of high chemical variability and show superior perfor-
mance in the activation of unsaturated substrates such as acetylene. The normal-
ized polymerization activity in dimethyl sulfoxide (DMSO) of 500 mol polymer-
ized acetylene per mol nickel (h atm) -1 by far exceeds that of structurally related
phosphane catalysts by a similar order of magnitude as observed in ethylene poly-
merizations (see Sections 1.2 and 1.3.1). To our knowledge this activity even ex-
ceeds that of all other nickel catalysts reported so far (Fig. 1.4).
1.7.2
MATPAC, Novel Highly Polar Matrix Polyacetylenes [21, 22]
The high polar group tolerance of ylide nickel catalysts enables the polymerization
of acetylene in polymer solutions not only of low polarity but also of medium and
high polarity. These options provide synthetic access to a wide range of novel ma-
trix polyacetylenes (MATPAC). Examples of polymers that may be used as matrix