Dehydrocoupling Polymerization: Poly(silylether) Synthesis by Using an Iron Β‐diketiminate Catalyst

We describe the iron-catalyzed polymerizations of diol and silane monomers to obtain fourteen different poly(silylether) products with number average molecular weights (M-n) up to 36.3 kDa. The polymerization reactions developed in this study are operationally simple and applicable to 1 degrees and 2 degrees silane monomer substrates and a range of benzylic and aliphatic diol substrates as well as one polyol example. The polymers were characterized by IR spectroscopy, DSC and TGA and, where solubility allowed, H-1, C-13{H-1}, Si-29{H-1} NMR spectroscopies, GPC and MALDI-TOF were also employed. The materials obtained displayed low T-g values (-70.6 to 19.1 degrees C) and were stable upon heating up to T--5%,T-Ar 421.6 degrees C. A trend in T--5%,T-Ar was observed whereby use of a 2 degrees silane leads to higher T--5%,T-Ar compared to those obtained using a 1 degrees silane. Reaction monitoring was undertaken by in situ gas evolution studies coupled with GPC analysis to follow the progression of chain-length growth which confirmed a condensation polymerization-type mechanism.