Improved Reactivity in the Ring-Opening Polymerization of ε-Caprolactone with a Trinuclear Titanium(IV) Oxochloroneopentoxide as Initiator
| Autor: | Giovana G. Nunes, Sônia Faria Zawadzki, Jaísa F. Soares, Eduardo L. de Sá, André Luis Rüdiger, David L. Hughes, Thiago da Silva, Siddhartha O. K. Giese |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
ring-opening polymerization
Dispersity Inorganic chemistry trinuclear alkoxide Solution polymerization General Chemistry crystal structure analysis Medicinal chemistry Ring-opening polymerization titanium(IV) chemistry.chemical_compound Monomer chemistry Polymerization Alkoxide Reactivity (chemistry) Caprolactone ε-caprolactone |
| Zdroj: | Journal of the Brazilian Chemical Society v.28 n.8 2017 Journal of the Brazilian Chemical Society Sociedade Brasileira de Química (SBQ) instacron:SBQ Journal of the Brazilian Chemical Society, Volume: 28, Issue: 8, Pages: 1440-1452, Published: AUG 2017 |
| Popis: | The complex [Ti3(O)(Cl)(ONep)9] and two iron(II)-containing products, [Fe4Cl8(thf)6] and [Fe2Cl3(thf)6][FeCl4], were synthesized by a redox reaction involving [Ti3(OiPr)11][FeCl4] and neopentanol; the structures of compounds [Ti3(O)(Cl)(ONep)9] and [Fe2Cl3(thf)6][FeCl4] have been confirmed by X-ray diffraction methods. Variable-temperature 1H NMR analysis of [Ti3(O)(Cl)(ONep)9] revealed signals for three non-equivalent neopentoxides in the 1:1:1 integration ratio, indicating the maintenance of the trinuclear structure in solution. Alkoxide [Ti3(O)(Cl)(ONep)9] was employed as initiator in both bulk and solution polymerization of e-caprolactone (e-CL) at various temperatures, monomer/initiator molar ratios and reaction times. [Ti3(O)(Cl)(ONep)9] produced poly(e-caprolactone) in high yields, with molecular weights ranging from 7100 to 9800 g mol-1 and PDI (polydispersity index) values between 1.3 to 1.5. The reactivity of [Ti3(O)(Cl)(ONep)9] in the ring-opening polymerization (ROP) of e-CL was compared to those of [Ti3(OiPr)11][FeCl4] and [Ti(OiPr)4]. The better polymerization reactivity shown by [Ti3(O)(Cl)(ONep)9] seems to be associated with structural features, as well as with the stronger Lewis basicity of -ONep over -OiPr ligands and the maintenance of the trimetallic structure in the reaction media. |
| Databáze: | OpenAIRE |
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