The complex [Ti 3 (O)(Cl)(ONep) 9 ] and two iron(II)-containing products, [Fe 4 Cl 8 (thf) 6 ] and [Fe 2 Cl 3 (thf) 6 ][FeCl 4 ], were synthesized by a redox reaction involving [Ti 3 (O i Pr) 11 ][FeCl 4 ] and neopentanol; the structures of compounds [Ti 3 (O)(Cl)(ONep) 9 ] and [Fe 2 Cl 3 (thf) 6 ][FeCl 4 ] have been confirmed by X-ray diffraction methods. Variable-temperature 1 H NMR analysis of [Ti 3 (O)(Cl)(ONep ) 9 ] revealed signals for three non-equivalent neopentoxides in the 1:1:1

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... ation ratio, indicating the maintenance of the trinuclear structure in solution. Alkoxide [Ti 3 (O)(Cl)(ONep) 9 ] was employed as initiator in both bulk and solution polymerization of ε-caprolactone (ε-CL) at various temperatures, monomer/initiator molar ratios and reaction times. [Ti 3 (O)(Cl)(ONep) 9 ] produced poly(ε-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 [Ti 3 (O)(Cl)(ONep) 9 ] in the ring-opening polymerization (ROP) of ε-CL was compared to those of [Ti 3 (O i Pr) 11 ][FeCl 4 ] and [Ti(O i Pr) 4 ]. The better polymerization reactivity shown by [Ti 3 (O)(Cl)(ONep) 9 ] seems to be associated with structural features, as well as with the stronger Lewis basicity of −ONep over −O i Pr ligands and the maintenance of the trimetallic structure in the reaction media.