Pentamethylcyclopentadienyl molybdenum(V) complexes derived from iodoanilines: Synthesis, structure, and rop of ε-caprolactone

Xing, Tian; Elsegood, Mark R. J.; Dale, Sophie H.; Redshaw, Carl

Abstract

The reaction of [Mo(η-C5Me5 )Cl4 ] with the ortho-, meta-, or para-iodo-functionalized anilines 2-IC6H4NH2, 3-IC6H4NH2, 4-IC6H4NH2 yields imido or amine products of the type [Mo(ηC5Me5 )Cl2 (IC6H4N)] (2-I, 1, 3-I, 3, 4-I, 5) or [Mo(η-C5Me5 )Cl4 (IC6H4NH2 )] (3-I, 2, 4-I, 4), respectively, depending on the reaction stoichiometry/conditions; we were unable to isolate an amine complex of the 2-I derivative. The reaction of [Mo(η-C5Me5 )Cl4 ] with one equivalent of 2-I,4-FC6H3NH2 in the presence of Et3N afforded [Mo(η-C5Me5 )Cl2 (2-I,4-FC6H3N)]·MeCN (6·MeCN), which, upon exposure to air, afforded the Mo(VI) imido complex [Mo(η-C5Me5)Cl3 (2-I,4-FC6H3N)] (7). For comparative studies, the structure of the aniline (C6H5NH2 )-derived complex [Mo(η-C5Me5 )Cl2 (2-C6H3N)] (8) has also been prepared. The molecular structures of 1–8 have been determined and reveal packing in the form of zig-zag chains or ladders. The complexes catalyze, in the presence of benzyl alcohol under N2, the ring-opening polymerization (ROP) of ε-caprolactone affording relatively low molecular weight products. The MALDI-ToF spectra indicate that a number of polymer series bearing a variety of end groups are formed. Conducting the ROPs as melts or under air results in the isolation of higher molecular weight products, again bearing a variety of end groups. Kinetic studies reveal the aniline-derived imido complex 8 performs best, whilst a meta-iodo substituent and a Mo(V) centre are also found to be beneficial. The structures of the side products 2-IC6H4NH3Cl and 3-IC6H4NH3Cl are also reported.

Citation

Xing, T., Elsegood, M. R. J., Dale, S. H., & Redshaw, C. (2021). Pentamethylcyclopentadienyl molybdenum(V) complexes derived from iodoanilines: Synthesis, structure, and rop of ε-caprolactone. Catalysts, 11(12), Article 1554. https://doi.org/10.3390/catal11121554

• Journal Article Type: Article
• Acceptance Date: Dec 2, 2021
• Online Publication Date: Dec 20, 2021
• Publication Date: Dec 20, 2021
• Deposit Date: Dec 21, 2021
• Publicly Available Date: Dec 22, 2021
• Journal: Catalysts
• Print ISSN: 2073-4344
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 12
• Article Number: 1554
• DOI: https://doi.org/10.3390/catal11121554
• Keywords: Imido; Amine; Iodo; Molybdenum; Structure; Ring opening polymerization
• Public URL: https://hull-repository.worktribe.com/output/3902718