Cyclometalated Platinum(Ii) Complexes Simultaneously Catalyze The Cross-Linking Of Polysiloxanes And Function As Luminophores

A family of the C,N-cyclometalated species [Pt(ppy)Cl(PPh3)], [Pt(ppy)Cl(CNCy)], [Pt(ppy)(CNCy)(PPh3)](OTf), and [Pt(ppy)(CNCy)(2)](BF4) (ppy = 2-phenylpyridinato-C-2,N; Cy = cyclohexyl) was generated from [Pt(ppy)(mu-Cl)](2), CNCy, and PPh3. The obtained platinum(II) complexes were characterized by high-resolution ESI+-MS, IR, and 1D (H-1, C-13{H-1}, Pt-195{H-1}) and 2D (H-1,H-1-NOESY; H-1,C-13-HSQC; H-1,C-13-HMBC) NMR spectroscopy, and the latter three complexes were investigated by X-ray diffraction. All four platinum species were examined as hydrosilylation catalysts (c 10(-4)-10(-3) M; 80-120 degrees C; [Pt(ppy)Cl(PPh3)] exhibited the highest catalytic activity) for the cross-linking of vinyl-terminated polydimethylsiloxane and polymethylhydrosiloxane to achieve luminescent silicone rubbers. Each solid complex and the appropriate silicone rubber exhibited the same emission spectra in the green region and strong phosphorescence with a solid-state quantum yield of up to 12.5% (measured for the silicone elastomer obtained with the [Pt(ppy)(CNCy)(2)](BF4) catalyst). The resulting luminescent silicone rubbers can be potentially used for protective coatings (to facilitate the thickness control) and as a component for phosphor-converted white light-emitting diodes (to transform a UV part of the LED emission to the visible spectrum).