Process for the preparation and use of platinum-organosiloxane complex.

The invention relates to a platinum-organosiloxane complex preparation process. The method comprises reacting a platinum halide with an organosiloxane having from 2 to 4 silicon-bonded organic groups having 2 to 6 carbon atoms and containing a terminal olefinic unsaturation, the reaction being carried out in the presence of a liquid polar organic, for example dimethylformamide or butan-2-one, which is a solvent at least part of platinum halide. These complexes are useful as catalysts for hydrosilylation reactions. Application to coatings, encapsulation and other silicone.