High‐temperature platinum‐catalyzed hydrosilylation and dehydrocoupling cross‐linking of silicones

We propose to use the platinum(II) C , N ‐cyclometalated complex (PCC) to catalyze the hydrosilylation and dehydrocoupling reactions of high molecular weight polysiloxanes at elevated temperatures (above 100°C). PCC was prepared via a three‐step procedure consisting of the 2‐hydrazinopyridine synthesis, its treatment with 3‐methoxy‐4‐(prop‐2‐yn‐1‐yloxy)benzaldehyde, and coupling of the obtained product with cis ‐[PtCl 2 (CNXyl) 2 ]. This complex exhibits thermal stability up to 150°C even at heating in air. PCC allows carrying out the cross‐linking of vinyl‐terminated polydimethylsiloxane (V‐PDMS) and polymethylhydrosiloxane (PMHS) by hydrosilylation, as well as PMHS dehydrocoupling cross‐linking at 150 and 120°C, respectively. The coupling (cross‐linking) patterns were successfully confirmed by 1 H, 13 C, and 29 Si solid‐state NMR spectroscopy. The thermal and swelling characteristics and the transparency of the obtained silicone materials indicate the absence of aggregation of platinum particles.