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Tertiary arsine-stabilised arsenium salts: Syntheses and comparisons with phosphine analogues
journal contribution
posted on 2023-05-17, 17:18 authored by Nathan KilahNathan Kilah, Weir, ML, Wild, SBThe first tertiary arsine-stabilised arsenium salts, [(L)AsMePh]OTf (L = Ph3As, Me2PhAs, [2-(MeOCH2)C6H4]Ph2As, [2-(MeOCH2)C6H4]Me2As), have been prepared by chloride abstraction from chloromethylphenylarsine with trimethylsilyl triflate in the presence of the arsine. The complexes have been characterised by crystallography and 1H NMR spectroscopy. The chiral cations in the complexes have structures based on the trigonal pyramid in which the arsine is coordinated orthogonally to the prochiral, six-electron MePhAs+ ion that forms the base of the pyramid. The NMR data for the complexes in dichloromethane-d2 are consistent with rapid exchange of the arsine on the arsenium ion, even at 183 K. The corresponding phosphine-stabilised complexes are considerably more stable than their arsine counterparts in dichloromethane-d2 with the free energy of activation ΔG‡c = ca. 60 kJ mol-1 being calculated for phosphine exchange in [(Me2PhP)AsMePh]OTf at 281 K; for [(Me2{2-(MeOCH2)C6H4}P)AsMePh]OTf in the same solvent, ΔG‡c = ca. 70 kJ mol-1 at 323 K.
History
Publication title
Dalton TransactionsIssue
18Pagination
2480-2486ISSN
1477-9226Department/School
School of Natural SciencesPublisher
Royal Soc ChemistryPlace of publication
Thomas Graham House, Science Park, Milton Rd, Cambridge, England, Cambs, Cb4 0WfRights statement
Copyright 2008 The Royal Society of ChemistryRepository Status
- Restricted