Photopolymerization of Epoxides with Platinum(II) Bis(acetylacetonato)/Silane Catalysts

Abstract

Photopolymerization of epoxides in the presence of silanes RSi3H and platinum(II) bis-(acetylacetonato) complexes is reported. The catalytic reactivity of the platinum complexes depended on the concentration ratio of silane/platinum complex to monomer and the molecular structure of the silanes, as well as the structure of the platinum complexes. A mechanism is proposed.

Highly Active Cationic Rhodium(I) Precatalysts for the Ambient Temperature Ring-Opening Polymerization of [1]Silaferrocenophanes and Tetramethyldisilacyclobutane

“…Isolation of the resulting polymer 7 via precipitation into MeOH afforded a white fibrous material of very high molecular weight in 80% yield ( M n = 1.08 × 10 6 , PDI = 1.39). Thus, [Rh(1,5-cod) 2 ]OTf represents a highly active catalyst for the ROP of 6 , with only the platinum-based photocatalyst, Pt(acac) 2 , exhibiting superior catalytic activity. , Importantly, in contrast to the degradation of 2a following [Rh(1,5-cod) 2 ]OTf-initiated ROP of 1a , no decrease in molecular weight was detected for 7 . Indeed, the molecular weights of 7 were unchanged over a period of 7 days.…”

Solvent‐free ring‐opening polymerization of cyclohexene oxide catalyzed by palladium chloride

“…The thermal latent catalysis polymerization of CHO is widely used in industry, but it often has a poor polymerization yield, and the catalysts usually require tedious multistep process to synthesize. Considerable efforts have been devoted to finding new catalysts with improved CHO polymerization yield . Onium compounds (eg, iodonium, pyridinium, and sulfonium salts) and metal complexes have been reported to show catalytic activity when aided by light and/or a cocatalyst.…”

“…Considerable efforts have been devoted to finding new catalysts with improved CHO polymerization yield. [9][10][11][12][13][14][15][16][17][18][19] Onium compounds [9][10][11][12][13][14][15] (eg, iodonium, pyridinium, and sulfonium salts) and metal complexes 16,17 have been reported to show catalytic activity when aided by light and/or a cocatalyst.…”

Infrared Spectroscopy - Materials Science, Engineering and Technology

“…Additionally, a protecting effect of axial and equatorial protons of the cyclohexyl ring against nucleophilic attack has been proposed as an explanation of the characteristic low reactivity of the oxirane ring in these aliphatic epoxies (Soucek et al, 1998). This way, the best performance and the highest crosslinking degree for DGEBA-based resins is achieved when cured via an addition mechanism with diamines (either aliphatic or aromatic), whilst cycloaliphatic epoxies are commonly cured with anhydrides (Barabanova et al, 2008;Chen et al, 2002;Tao et al, 2007;Wang et al, 2003) or homopolymerized via a cationic mechanism induced by UV radiation (Crivello, 1995;Crivello & Fan,1991;Crivello & Liu, 2000;Wang & Neckers. 2001;Yagci & Reetz, 1998).…”