| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 475.37 KB | Adobe PDF |
Advisor(s)
Abstract(s)
The living polymerisation of mono and difunctional phenylethynylcalix[4]arene compounds 1 and 2 by Rh(I) ternary catalytic systems (TCS) was examined. Two TCS were tentatively prepared in situ, adapting known methodologies: (1) Rh(CuCPh)(norbornadiene)(PPh3) and (2) Rh(C(Ph)CvCPh2)(norbornadiene)(PPh3). Using the first TCS, the conjugated polymers poly 1 and poly 2 could be obtained in very good yields (77–86%), in short reaction times and freed from low-molecular-weight products, only when NEt3 was used as a co-catalyst. With the second TCS, excellent results were obtained. Indeed,thiscatalyticsystemprovedtobequiteefficientin thepolymerisation ofcalix[4]arenes 1and 2, affording the correspondent poly 1 and poly 2 essentially in almost quantitative yields (by GPC analysis), under appropriate conditions. The living nature of the polymerisation has been proved. For instance, in the case of calix[4]arene 1, the Mn of the polymer obtained at high monomer conversion increased proportionally with the [1]:[Rh] molar ratio in the feed, keeping [1]o constant, thus showing that irreversible chain transfer or termination reactions did not occur to a major extent. Under the most favourable conditions {[1]:[Rh] 5 50 and [2]:[Rh] 5 50}, the polydispersities of poly 1 and poly 2 were kept in a narrow range (1.16–1.30).
Description
Keywords
Calixarene Conjugated polymers Living polymerisation Rhodium Transition metal catalyst Dimerisation
Citation
COSTA, Alexandra I.; PRATA, José V. – Studies towards the living polymerisation of phenylethynyl-calix[4]arene compounds with rhbased ternary catalytic systems. Supramolecular Chemistry. ISSN 1061-0278. Vol. 20, N.º 1-2 (2008), pp. 95-108
Publisher
Taylor & Francis