POLY 125 |
| The reducing power of several copper, ruthenium, and osmium atom transfer radical polymerization (ATRP) catalysts was quantified with cyclic voltammetry in tetrahydrofuran, including for MtX2(PPh3)3, MtX(Cp*)PiPr3, and CuX2(BPMODA) (where Mt = Ru and Os, X = Cl and Br, and BPMODA = N,N,-bis(2-pyridylmethyl)octadecylamine). Spectrophotometric measurements are used to determine ATRP equilibrium constants (KATRP) for the complexes. OsBr(Cp*)PiPr3 proved one of the most active ATRP complexes known to date (KATRP with 1-phenylethyl bromide in tetrahydrofuran = 3.2x10-5), being over 10,000 times more active than its RuCl(Cp*)PiPr3 analogue. Ru and Os catalysts of comparable activity to Cu are approximately 500 mV less reducing. Evaluation of E1/2 and KATRP values allowed the indirect determination that halogen affinities of these Ru and Os compounds must be approximately 7-9 orders of magnitude stronger than typical Cu ATRP catalysts to compensate for their comparatively poor reducing power. |
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General Papers: Functional Materials
6:00 PM-8:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Polymer Chemistry |