Versatile organoaluminium catalysts based on heteroscorpionate ligands for the preparation of polyesters

Martinez, J.; de Sarasa Buchaca, M. Martinez; de la Cruz-Martinez, F.; Alonso-Moreno, C.; Sanchez-Barba, L. F.; Fernandez-Baeza, J.; Rodriguez, A. M.; Rodriguez-Dieguez, A.; Castro-Osma, J. A.; Otero, A.; Lara-Sanchez, A.


A series of alkyl aluminium complexes based on heteroscorpionate ligands were designed as catalysts for the ring-opening polymerisation of cyclic esters and ring-opening copolymerisation of epoxides and anhydrides. Treatment of AlX3 (X = Me, Et) with ligands bpzbeH [bpzbe = 1,1-bis(3,5-dimethylpyrazol-1-yl)-3,3-dimethyl-2-butoxide], bpzteH [bpzte = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-para-tolylethoxide], and (R,R)-bpzmmH [(R,R)-bpzmm = (1R)-1-{(1R)-6,6-dimethyl-bicyclo[3.1.1]-2-hepten-2-yl}-2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide] for 2 hours at 0 degrees C afforded the mononuclear dialkyl aluminium complexes [AlMe2{kappa(2)-bpzbe}] (1), [AlEt2{kappa(2)-bpzbe}] (2), [AlMe2{kappa(2)-(R,R)-bpzmm}] (3) and [AlEt2{kappa(2)-(R,R)-bpzmm}] (4), and the dinuclear dialkyl complexes [AlMe2{kappa(2)-bpzte}](2) (5) and [AlEt2{kappa(2)-bpzte}](2) (6). The molecular structures of the new complexes were determined by spectroscopic methods and confirmed by X-ray crystallography. The alkyl-containing aluminium complexes can act as highly efficient single-component initiators for the ring-opening polymerisation of epsilon-caprolactone and L-lactide and for the ring-opening copolymerisation of cyclohexene oxide and phthalic anhydride to give a range of biodegradable polyesters.

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Título según WOS: ID WOS:000434313900012 Not found in local WOS DB
Título de la Revista: DALTON TRANSACTIONS
Volumen: 47
Número: 22
Fecha de publicación: 2018
Página de inicio: 7471
Página final: 7479


Notas: ISI