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Combinatorial Catalysis with Bimetallic Complexes: New Efficient Catalysts for Atom Transfer Radical Polymerization

English title Combinatorial Catalysis with Bimetallic Complexes: New Efficient Catalysts for Atom Transfer Radical Polymerization
Applicant Rechavi-Robinson Dalit
Number 114355
Funding scheme Marie Heim-Voegtlin grants
Research institution Institut des sciences et ingénierie chimiques EPFL - SB - ISIC
Institution of higher education EPF Lausanne - EPFL
Main discipline Inorganic Chemistry
Start/End 01.11.2006 - 29.02.2008
Approved amount 120'471.00
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All Disciplines (2)

Discipline
Inorganic Chemistry
Organic Chemistry

Keywords (4)

ATRP; polymerisation; bimetallic complexes; combinatorial catalysis

Lay Summary (English)

Lead
Lay summary
Polymers are of major importance to the chemical industry as well as in everyday life. Atom transfer radical polymerization (ATRP) is emerging as a new polymerization method with potential for obtaining well-defined polymers (with low polydispersity). This polymerization method requires catalysis, and the catalysts used are left trapped within the polymer. It is therefore necessary to find very efficient catalysts, so that their quantity in the polymer would be negligible. The aim of this project is to find new and efficient catalysts for ATRP.The role of the catalysts in ATRP reactions is to generate a radical species via reversible abstraction of the halogen at the polymer terminal.The radical can then undergo propagation by reacting with other monomers.Since the mechanism of the ATRP reaction is complex, rational design of catalysts is difficult. Especially, it is hard to predict which subtle differences could lead to an improvement in the efficiency of the catalysts. We shall therefore use combinatorial catalysis to scan many potential catalysts for this reaction. Bimetallic halogeno-bridged complexes, which can easily be generated in situ from accessible monometallic complexes, have recently been shown by the group of Professor Kay Severin (http://isic2.epfl.ch/page59057.html) to be good catalysts for Atom Transfer Radical Addition (ATRA) reactions of CCl4 to styrene. Due to the presence of the labile halogeno-bridges, the complexes generally show a high intrinsic reactivity. Dimeric complexes of Ru(II), Ru(III), Ru(IV), Rh(I), Rh(III), Ir(I), Ir(III), Pd(II), and Pt(II) will be employed. The two metal fragments can include different metals, so as to form hetero bimetallic complexes. Since the ATRA and the ATRP reactions are mechanistically related, the same type of complexes will be tested in ATRP reactions. The Severin group has already described the successful use of one such catalyst in ATRP reactions. An effort will also be made towards the polymerization of monomers which are not easily polymerized by well-known catalysts.
Direct link to Lay Summary Last update: 21.02.2013

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