Cyclic Polysiloxanes with Linked Cyclotetrasiloxane Subunits

Cyclic polymers are an important class of macromolecules, but the structural diversity of the backbone is limited. Herein we report the use of the Piers–Rubinsztajn reaction for the one-step synthesis of cyclic polysiloxanes with novel structural features. Specifically, the B(C₆F₅)₃-catalyzed coupling of various organic tris(dimethylsiloxy)silane and trialkoxysilane compounds generated a series of cyclic polysiloxanes with cyclotetrasiloxane subunits. The thiolated cyclic polymers were also shown to be effective in directing the circular assembly gold nanoparticles. The presence of constrained rings in the backbone is unprecedented and may offer opportunities for novel applications of these cyclic polymers.