In this work, we describe the SuFEx-based polycondensation between bisalkylsulfonyl fluorides (AA monomers) and bisphenol bis(t-butyldimethylsilyl) ethers (BB monomers) using [Ph3P=N-PPh3]+[HF2]− as the catalyst. The AA monomers were prepared via the highly reliable Michael addition of ethenesulfonyl fluoride and amines/anilines while the BB monomers were obtained from silylation of bisphenols by t-butyldimethylsilyl chloride. With these reactions, we were able to achieve a remarkable diversity of monomeric building blocks by exploiting readily available amines, anilines, and bisphenols as starting materials. The SuFEx-based polysulfonate formation reaction exhibited excellent efficiency and functional group tolerance, producing polysulfonates with a variety of side chain functionalities in >99% conversion within 10 min to 1 h. When bearing an orthogonal group on the side chain, the polysulfonates can be further functionalized via click-chemistry based post-polymerization modification.
Mechanisms and reactivity differences for the cycloaddition of anhydride to alkyne catalyzed by the palladium and nickel catalysts have been investigated by extensive density functional theory (DFT) calculations. The predicted free energy profiles for the Pd- and Ni-catalyzed reactions have been used to evaluate possible mechanisms for the formation of different products. Calculations show that the formation of isocoumarin via the decarbonylative addition of anhydride to alkyne is kinetically more favorable than the channel to indenone in the Ni-catalyzed reaction. On the contrary, the preparation of naphthalene through sequential liberation of CO2 and CO is kinetically more favorable than that the formation of indenone in the Pd-catalyzed process. The bonding differences between Pd-C and Ni-C bonds, arising from the relativistic effect of late transition metals, play an important role in regulating their catalytic activity. The calculation results show good agreement with the experiments.
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