Nearly monodisperse CdSe nanoclusters, surface-passivated with a layer of trioctylphosphine and trioctylphosphine oxide, have been sequestered within phosphine-containing domains in a diblock copolymer. A convergent approach to fabrication of these composites was adopted via independent synthesis of nanoclusters and polymer. Diblock copolymers of phosphine- or phosphine oxide-functionalized monomers and methyltetracyclododecene (MTD) were prepared by ring opening metathesis polymerization using Mo alkylidene initiators. Nanoclusters were prepared by pyrolysis of CdMe2 and SeP(octyl)3 in the presence of P(octyl)3 and OP(octyl)3. An immediate and sustained increase in electronic passivation is found for nanoclusters incorporated into octylphosphine-containing polymers. In contrast, nanoclusters in pure hydrocarbon or phosphine oxide-containing polymers rapidly lose passivation. Films of nanoclusters in a phosphine-containing polymer matrix were static cast from dilute solution. Under suitable conditions, th...

Fabrication of Quantum Dot/Polymer Composites: Phosphine-Functionalized Block Copolymers as Passivating Hosts for Cadmium Selenide Nanoclusters

Vinylic addition polynorbornenes bearing functional groups can be obtained in a versatile way by nucleophilic substitution of a halogen in new vinylic haloalkyl polynorbornenes. The latter are obtained by vinylic homo and copolymerization of norbornene and haloalkyl norbornenes catalyzed by [Ni(C6F5)2(SbPh3)2]. This method circumvents the problem of catalyst deactivation encountered in classical copolymerizations with polar monomers. The content of substituted monomer in the copolymers is in the range 26−59%, depending on the monomer ratio in the feed. Nucleophilic substitution reactions afford polymers with ester, cyano, phenylthio, or azido groups in the same wide range of composition. Click chemistry on the azido polynorbornenes give polynorbornenes with pendant triazole groups.

Versatile Route to Functionalized Vinylic Addition Polynorbornenes

Use of diisocyanates for in situ preparation of nitrile oxides : preparation of isoxazoles and isoxazolines

The Stille coupling can be carried out in a batch process using insoluble tin supports. The new type of support consists of stannylated polymers based on the vinylic polynorbornene skeleton that allow one to use a set-up where the tin reagent is immobilized in a column. The immobilized stannylated polymeric reagent can be easily reused. The coupling products are thus obtained by a very simple work-up procedure and have very low levels of tin contamination.

Batch Stille Coupling with Insoluble and Recyclable Stannylated Polynorbornenes

3 – Magnesium, Calcium, Strontium and Barium

Le chlorure de norbornenyl-5methyl magnesium subit des transpositions chimiques avec ouverture de cycle pour donner un bicyclo [3.3.0] octene-2, un allyl-3 cyclopentene-1, un allyl-1 ou 2 cyclopentadiene-1,3. Les mecanismes de reaction sont discutes

Heidi Sonnentag

Papers

Rearrangement and cleavage of the Grignard reagent from 5-(chloromethyl)norbornene