Control of radical reactions mediated by bimetallic systems

Poster (2001)

We present herein preliminary results on the use of Ti-Ru bimetallic catalyst systems in Kharasch chemistry and atom transfer radical polymerisation

Synthesis and evaluation of new RuCl2(p-cymene)(ER2R') and (eta(1):eta(6)-phosphinoarene)RuCl2 complexes as ring-opening metathesis polymerization catalysts

in Journal of Organometallic Chemistry (2000), 606(1), 55-64

New RuCl2(p-cymene)(ER2R') complexes (E = P, As, Sb; R, R' = H, alkyl, arylalkyl) have been synthesized and used as catalyst precursors for the ring-opening metathesis polymerization (ROMP) of cyclooctene ... [more ▼]

New RuCl2(p-cymene)(ER2R') complexes (E = P, As, Sb; R, R' = H, alkyl, arylalkyl) have been synthesized and used as catalyst precursors for the ring-opening metathesis polymerization (ROMP) of cyclooctene, cyclopentene, and norbornene. When ER2R' was a phosphinoarene, the p-cymene ligand could be displaced upon heating and tethered (eta(1):eta(6)-phosphinoarene)RuCl2 complexes were obtained. Simple thermogravimetric analysis (TGA) of the complexes provided clear-cut indication on their potential catalytic activity in ROMP. (C) 2000 Elsevier Science S.A. All rights reserved. [less ▲]

Highly stereoselective ruthenium-catalyzed ring-opening metathesis polymerization of 2,3-difunctionalized norbornadienes and their 7-oxa analogues

in Macromolecules (1999), 32(7), 2091-2103

The ring-opening metathesis polymerization (ROMP) of 2,3-difunctionalized norbornadienes and their 7-oxa analogues catalyzed by [RuCl2(p-cymene)](2) in the presence of trimethylsilyldiazomethane (TMSD ... [more ▼]

The ring-opening metathesis polymerization (ROMP) of 2,3-difunctionalized norbornadienes and their 7-oxa analogues catalyzed by [RuCl2(p-cymene)](2) in the presence of trimethylsilyldiazomethane (TMSD) yields high-trans, highly tactic polymers. A tentative mechanism involving arene loss, carbene formation, and monomer chelation is presented. The ROMP of 2,3-dicarbomethoxynorbornadiene served as a test reaction to investigate the influence of the various experimental parameters (reaction time and temperature, nature of the solvent and catalyst, and TMSD initiation conditions). An all-trans, highly tactic (>79%) polymer was obtained under a wide variety of conditions. Strikingly, the addition of tricyclohexylphosphine had a detrimental influence on the polymerization yield and stereoselectivity. The procedure was successfully applied to various other 2,3-dicarboalkoxynorbornadienes, benzonorbornadiene, and their 7-oxa analogues. In the case of the diester monomers, an increase in the alkyl substituent size led to a decrease of the polymer trans content and tacticity. Because of the ruthenium catalyst's ready availability and marked resistance to oxygen and water, reactions were very easy to set up and to carry out. [less ▲]

Synthesis of poly(norbornene-g-ε-caprolactone) copolymers by sequential controlled ring opening polymerization

in Polymer Bulletin (1998), 40(6), 631-638

Poly(norbornene-g-ε-caprolactone) copolymers have been prepared by the "grafting from" technique. Well controlled polynorbornene containing 5% acetate pendant groups has been firstly synthesized by ... [more ▼]

Poly(norbornene-g-ε-caprolactone) copolymers have been prepared by the "grafting from" technique. Well controlled polynorbornene containing 5% acetate pendant groups has been firstly synthesized by ruthenium complex-mediated ring opening metathesis polymerization. The acetate groups have been derivatized into aluminum alkoxides by hydrolysis into alcohol followed by reaction of the alcohol with triethylaluminum. The two polymerization steps are under complete control, so that graft copolymers have been synthesized with a narrow molecular weight distribution and are free from any detectable traces of the parent homopolymers as stated by selective fractionation experiments. These original copolymers have been characterized by SEC, FTIR, 1H NMR, DSC, TGA. [less ▲]

Ligand effects in the hydrogenation of methacycline to doxycycline and epi-doxycycline catalysed by rhodium complexes. Molecular structure of the key catalyst [closo-3,3-(η2,3-C7H7CH2)-3,1,2-Rh C2B9H11]

Poster (1993, December)

Stereoselective hydrogenation of methacycline to doxycycline catalysed by rhodium-carborane complexes

in Tetrahedron Letters (1993), 34

Application of high performance liquid chromatography to the determination of the optimized reaction conditions giving stereoselective hydrogenation of methacycline to doxycycline

Poster (1992, May 08)