Synthesis and characterisation of alkylaluminium benzimidazolates and their use in the ring-opening polymerisation of ε-caprolactone

Shen, Miao; Huang, Wei; Zhang, Wenjuan; Hao, Xiang; Sun, Wen Hua; Redshaw, Carl

Abstract

The stoichiometric reactions of 2-(benzimidazol-2-yl)-6-methylpyridine (L1) or 8-(benzimidazol-2-yl)quinaldine (L2) with trialkylaluminium reagents R 3Al (R = Me, Et and iBu) afforded the corresponding dialkylaluminium benzimidazolate complexes R2AlL (L1, R = Me (1), Et (2), iBu (3); L2 R = Me (4), Et (5), iBu (6)). Treatment of L1 with one or two equivalents of Et2AlCl led to the adducts EtAl(L1)2·AlEtCl 2 (7) or Et2AlL1·AlEtCl2 (8), respectively. Complex 7 was also available via treatment of 8 with one equivalent of L1. Reaction of L1 with two equivalents of AlR3 (R = Me or Et) afforded R2AlL1·AlR3 (R = Me, 9; R = Et, 10), which were also formed when 1 or 2 were reacted with AlR3. Reaction of L2 with two equivalents of AlR3 (R = Me or Et) gave the complexes R2AlL2·AlR3 (R = Me, 11; R = Et, 12), which were also formed in the stoichiometric reaction of 4 or 5 with AlR 3 (R = Me or Et). Screening of these complexes in the presence of BnOH, for the ring-open polymerisation of ε-caprolactone, revealed appreciable activities. Only the aluminium compounds ligated by 2-(benzimidazol-2-yl)-6-methylpyridine maintained high activity in the absence of BnOH. In all cases, polymers with bi- or multi-modal characteristics were produced.

Citation

Shen, M., Huang, W., Zhang, W., Hao, X., Sun, W. H., & Redshaw, C. (2010). Synthesis and characterisation of alkylaluminium benzimidazolates and their use in the ring-opening polymerisation of ε-caprolactone. Dalton Transactions : an international journal of inorganic chemistry, 39(41), 9912-9922. https://doi.org/10.1039/c0dt00514b

• Journal Article Type: Article
• Acceptance Date: Aug 9, 2010
• Online Publication Date: Sep 14, 2010
• Publication Date: Nov 7, 2010
• Deposit Date: Jun 8, 2022
• Journal: Dalton Transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 39
• Issue: 41
• Pages: 9912-9922
• DOI: https://doi.org/10.1039/c0dt00514b
• Public URL: https://hull-repository.worktribe.com/output/3622481