Triphenylantimony(V) o-amidophenolates with unsymmetrical N-aryl group for a reversible dioxygen binding

• Published in: Applied organometallic chemistry Vol. 25; no. 3; pp. 180 - 189
• Main Authors: Poddel'sky, Andrey I., Kurskii, Yury A., Piskunov, Alexandr V., Somov, Nikolay V., Cherkasov, Vladimir K., Abakumov, Gleb A.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.03.2011
• Subjects: antimony(V); Binding; dioxygen; Fragmentation; Isomers; Metalorganic compounds; Molecular structure; NMR spectroscopy; o-amidophenolate; Peroxides; redox-active ligand; X-ray analysis; X-rays
• ISSN: 0268-2605; 1099-0739; 1099-0739
• DOI: 10.1002/aoc.1738

New triphenylantimony(V) o‐amidophenolates (AP‐Me,Et)SbPh3 (1) and (AP‐Me,iPr)SbPh3 (2) with unsymmetrically substituted N‐aryl groups and (AP‐Et,Et)SbPh3 (3) with symmetrical N‐aryl group {AP‐R1,R2 is 4,6‐di‐tert‐butyl‐N‐[2‐alkyl(R1),6‐alkyl(R2)‐phenyl]‐o‐amidophenolate dianion} were synthesized and characterized in detail. Complexes were examined for dioxygen activity. The unsymmetrical complexes 1 and 2 were found to form different geometrical isomers (A and B) of spiroendoperoxides [L‐R1,R2(O2)]SbPh3 (4 and 5, respectively) with different dispositions of peroxide group and N‐aryl fragment (methyl and peroxide group are on the same side of the molecule in the less shielded isomer A, and on different sides in the more hindered isomer B). The isomer A prevails over isomer B, reflecting the possibility of steric control on the dioxygen‐binding reaction. Complex 3, where R1 = R2 = Et, formed the isomers 6A and 6B as 50:50. The ratio 4A:4B was 60:40 (for methyl‐ethyl containing complex 4) and it increased up to 80:20 for methyl‐isopropyl‐containing 5. The molecular structure of isomers 4A and 4B was confirmed by X‐ray analysis. Copyright © 2010 John Wiley & Sons, Ltd. New triphenylantimony(V) o‐amidophenolates of (AP‐R1,R2)SbPh3 type with (un)symmetrically substituted N‐aryl groups were examined for dioxygen activity. The unsymmetrical complexes form geometrical isomers of spiroendoperoxide with different dispositions of peroxide group and N‐aryl fragment (less shielded isomer A and more shielded isomer B). The isomer A prevails over isomer B, reflecting the possibility of steric control on dioxygen‐binding reaction.