Metathesis photoinduced

Some catalysts, most notably W(CO)6 in a CC14 solution44,45 and systems based on molybdena 46 when irradiated, are effective in photoinduced metathesis. In fact, a photoreduced silica-supported molybdena proved to be the most active olefin metathesis catalyst.47... 

More recent results support the view that Lewis acids, on the interaction with metal carbonyls, may facilitate dissociation of a ligand to leave a vacant site for alkene coordination.75 Photochemical generation of carbene species [Eq. (12.20)], the crucial step in photoinduced metathesis, is a complicated, multistep process 74,76,77... 

Karlen, T., Ludi, A., Miihlebach, A., Bernhard, P. and Pharisa, C., Photoinduced Ringopening Metathesis Polymerisation of Strained Bicyclic Olefins with Ruthenium Complexes , J. Polym. Sci., A, Polym. Chem., 33, 1665-1674 (1995). 

Table IV also includes values of the ratio [M]/[F. where M refers to the initial rate of the photoinduced metathesis and [F represents the yields of the photoluminescence spectra of the catalysts at 295 K. These values are important identifying the reactivity of the active site since the reaction proceeds only when a propene molecule interacts with the charge-transfer excited state of the catalyst that acts as the precursor, and this interaction corresponds to the quenching of photoluminescence of the catalyst with C3H, (140).

Effect of Mo Content on the Excited State of Mo/Si02 Catalysts and the Rate of Photoinduced Metathesis ofCJf,... 

A. Hafner, A. Miihlehach, P. A. van der Schaff, One-componenet catalysts for thermal and photoinduced ring-opening metathesis polymerization, Angew. Chem., Int. Ed. Engl. 36 2121 (1997) A. Fiirsmer, L. Ackermann, A most user-friendly protocol for ring closing metathesis reactions, Chem. Commun. 95 (1999). 

The yield of photoinduced metathesis of propene over Mo03/Si02 at 25°C is higher on catalysts obtained by reaction of gaseous M0CI5 with surface silanol... 

NEW MATERIALS FROM THERMAL AND PHOTOINDUCED RING OPENING METATHESIS POLYMERISATION (ROMP/PROMP)... 

Material properties of olefin metathesis polymers made by thermal (ROMP) or photoinduced (PROMP) polymerization with ruthenium (Il)-salts and the later developed ruthenium-phosphines as catalysts are described. The low oxidative stability was improved by copolymerization with so-called "build-in" antioxidants (AOs), i.e. hindered phenols or aromatic amines bearing 2-norbornene units. 

Sriiam, S.R. (2002) Developing of self-healing polymer composites and photoinduced ring opening metathesis polymerization. Doctoral dissertation. Department of Chemistry, University of Illinois Urbana-Champaign. 

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