Cyclometalated Ruthenium(II) Complex as a Versatile Catalyst for Living/Controlled Radical Polymerization of Hydrophobic and Hydrophilic Monomers

Abstract

Summary: Cyclometalated complex, cis-[Ru(phpy)(phen)(MeCN) 2 ]PF 6 , bearing strongly bound ligands (phpy ¼ 2-phenylpyridine, phen ¼ 1, 10-phenantroline) and relatively labile (MeCN) ligands, in conjunction with ethyl 2-bromoisobutyrate (EBiB), was used for radical polymerization of three hydrophobic, styrene (St), methyl methacrylate (MMA), n-butyl acrylate (BA), and one hydrophilic, 2-hydroxyethyl methacrylate (HEMA), monomers. The polymerizations were fast and reasonably controlled; the molecular weights increased with conversion and were close to the calculated values. The best control was achieved in polymerization of St. The complex was able to mediate this polymerization with acceptable rate and level of control even at a monomer/catalyst ratio of 2000. The living character of the polymerizations was confirmed by chain extension experiments; the degree of polymer ''livingness'' was less for PMMA than for PSt. Because of ionic nature, the complex was well soluble in MeOH and thus catalyzed polymerization of HEMA under homogeneous conditions at 50 8C.

Atom Transfer Radical Polymerization of Methyl Methacrylate Mediated by Grubbs 1st and 2nd Generation Catalysts: Insight into the Active Species

“…Recently, the importance of the characteristics of complexes in relation to the nature of ligands in the coordination sphere has been highlighted in the radical polymerization of methacrylates when proceeding in the presence of Al(OiPr) 3 . [26][27][28] As previously seen, the presence of Al(OiPr) 3 plays an important role in the control of polymerizations; therefore, we proceed the UV-Vis spectroscopy study to observe what occurs in the reaction mixture (Figure 4). UV-Vis spectra were registered in the interval of 20 min for 3 h with 1 or 2 in presence or in the absence of Al(OiPr) 3 .…”