New complexes for ε-caprolactone polymerisation

• Main Author: Arbaoui, Abdessamad
• Published: University of East Anglia 2008
• Subjects: 547.638
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502042

The present study deals with the synthesis and characterisation of a number of new complexes incorporating main group and transition metals. The catalytic behaviour of these complexes for the ring opening polymerisation of ε-caprolactone is discussed. Iron and alkali metals complexes (1 - 8) bearing calixarene ligands were obtained by reacting [MFe(Or-Bu)₃(THF)]₂ (M = Na, K) with p-rer/-butylcalix[4, 6 and 8]arene (L¹H₄,L² H₆ and L³ H₈ respectively), p-ferr-butylhexahomotrioxacalix[3]arene (L⁴H₃) or p-tert-butyltetrahomodioxacalix[6]arene (L⁵H₆). Treatment of L⁵H₆ with ZnEt₂ afforded the hexanuclear complex [L⁵Zn₆Et⁴(OEt)₂(CH₃CN)₄] (9.4(CH₃CN)).Reaction of AIR₃ (R = Me, Et) with the macrocyclic Schiff base ligand L⁶H₂ afforded the complexes (L⁶A1R₂)₂ (R = Me (10), Et (11)), L⁷H₂(AlMe₂)₂ (12) and L⁷H₂(AlMe₂)₄ (13) respectively. Complexes 12 and 13 were obtained via methyl transfer to imine moieties of the macrocycle framework. The acyclic analogues of complexes 12 and 13 were synthesised for catalytic comparison, along with a series of dinuclear zinc complexes bearing Schiff base ligands, obtained by metal template synthesis.