Catalytic synthesis of a pH responsive cyclic polymer

Zhihui Miao, Tomohiro Kubo, Christopher D. Roland, Brent S. Sumerlin, Adam S. Veige.

Center for Catalysis, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
Center for Macromolecular Science & Engineering and George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States

Cyclic polymers possess unique properties compared to their linear counterparts, such as smaller hydrodynamic volume, and lower intrinsic viscosities due to the loss of chain end interactions. Cyclic polyacetylenes have been prepared with our pre-catalyst [^tBuOCO]W≡C(^tBu)(THF)₂ and their cyclic topologies were confirmed by physical and chemical analysis. Cyclic poly(p-methoxylphenylacetylene) was made and converted to cyclic poly (p-hydroxylphenylacetylene via demethylation using boron tribromide. The resulting polymer was found to be soluble in basic water solution. The linear analogue was also prepared to study the difference between the two samples. Infrared spectroscopy and ¹H NMR were used to confirm the demethylation and the formation of the hydroxyl groups. Ultraviolet–visible spectroscopy was also applied to study the polymers’ water soluble property. This marks the first time that a cyclic polyphenylacetylene derivative has been modified for water solubility.