Manganese coordination chemistry of bis(imino)phenoxide derived [2 + 2] Schiff-base macrocyclic ligands

Yang, Wenxue; Zhao, Ke-Qing; Wang, Bi-Qin; Redshaw, Carl; Elsegood, Mark R.J.; Zhao, Jiang-Lin; Yamato, Takehiko

Abstract

The [2 + 2] Schiff base macrocycles [2,2'-(CH₂CH₂)(C₆H₄N)₂-2,6-(4-RC₆H₃OH)]₂ (IʳH₂), upon reaction with MnCl₂ (two equivalents) afforded the bimetallic complex [Cl₃Mn(NCMe)][MnCl(IᵗᵇᵘH₂)] (2). Under similar conditions, use of the related [2 + 2] oxy-bridged macrocycle [2,2'-O(C₆H₄N=CH)₂4-RC₆H₃OH] (IIʳH₂), afforded the bimetallic complexes [(MnCl)₂IIʳ] (R = Me 3, tBu 4), whilst the macrocycle derived from 1,2-diaminobenzene and 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-methylenedibenzaldehyde (IIIH₄) afforded the complex [(MnCl)₂(III)]·2MeCN (5·2MeCN). For comparative studies, the salt complexes [2,6-(ArNHCH)₂-4-MeC₆H₂O][MnCl₃(NCMe)] (Ar = 2,4-Me₂C₆H₃, 6) and {[2,6-(ArNHCH)₂-4-MeC₆H₂O][MnCl}₂[MnCl₄]·8CH₂Cl₂ (Ar = 4-MeC₆H₄, 7·8CH₂Cl₂) were prepared. The crystal structures of 1 - 7 are reported (synchrotron radiation was necessary for complexes 1, 3 and 5). Complexes 1 - 7 (not 5) were screened for their potential to act as pre-catalysts for the ring opening polymerization (ROP) of ε-caprolactone; 3, 4 and 6, 7 were inactive, whilst 1 and 2 exhibited only poor activity low conversion (<15 %) at temperatures above 60 °C.

Citation

Yang, W., Zhao, K., Wang, B., Redshaw, C., Elsegood, M. R., Zhao, J., & Yamato, T. (in press). Manganese coordination chemistry of bis(imino)phenoxide derived [2 + 2] Schiff-base macrocyclic ligands. Dalton Transactions : an international journal of inorganic chemistry, 45(1), 226-236. https://doi.org/10.1039/c5dt03453a

• Acceptance Date: Nov 10, 2015
• Online Publication Date: Nov 10, 2015
• Deposit Date: Dec 11, 2015
• Publicly Available Date: Nov 23, 2017
• Journal: Dalton transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 45
• Issue: 1
• Pages: 226-236
• DOI: https://doi.org/10.1039/c5dt03453a
• Keywords: Schiff base
• Public URL: https://hull-repository.worktribe.com/output/382445
• Publisher URL: http://pubs.rsc.org/en/Content/ArticleLanding/2016/DT/c5dt03453a#!divAbstract
• Additional Information: Authors' accepted manuscript of article published in: Dalton transactions, 2016, v.45, issue 1.