pH-Responsive Ruthenium-Based Olefin Metathesis Catalysts: Controlled Ring-Opening Metathesis Polymerization in Alcoholic and Aqueous Media upon Acid Addition

Miles A. Dunbar, University of Southern Mississippi
Shawna L. Balof, University of Southern Mississippi
Adam N. Roberts, University of Southern Mississippi
Hans-Joerg Schanz, University of Southern Mississippi

Abstract

The new hexacoordinate catalysts (PCy3)(DMAP)(2-) Cl2Ru=CH(p-C6H4)CH2NMe2 (7) and (PCy3)(DMAP)(2-)Cl2Ru=CH(p-C6H4)N(CH3)(2) (8) have been synthesized via exchange of a PCy3 ligand for two DMAP ligands from their (PCy3)(2)Ru precursors 4 and 5 in a one-step reaction in high yield. The catalysts promoted controlled ROMP of two cationic exo-7-oxanorbornene derivatives under homogeneous conditions in various acidic protic media, including acidic aqueous media. Very low polydispersities were accomplished in TFE/0.1 M HClaq. (1:1 v/v) with PDIs as low as 1.05.