title: Metal ion hydrocarbon bidentate bonding in alkyl acetates, methyl alkanoates, alcohols and 1-alkenes: a comparative study.
abstract: The relative affinity of the monovalent metal ions Li+, Na+, Cu+and Ag+towards a series of aliphatic alkyl acetates and some selected 1-alkenes (P) was examined using the kinetic method. A detailed analysis of the dissociation characteristics of a series of mixed metal-bound dimer ions of the type P1-M+-P2and the evaluated proton affinities (PAs) of the monomers shows that the affinity of the cation towards long-chain alkyl acetates and alkenes (having a chain length ≤ C4) is markedly enhanced. In line with recent studies of nitriles, alcohols and methyl alkanoates, this is attributed to a bidentate interaction of the metal ion with the functional group or double bond and the aliphatic chain. In particular, the longer chain alkyl acetates, methyl alkanoates and alcohols show a remarkably similar behaviour with respect to silver ion hydrocarbon bonding. The Ag+adducts of the alkyl acetates dissociate by loss of CH3COOH. This reaction becomes more pronounced at longer chain lengths, which points to metal ion bidentate formation in [Ag+···1-alkene] product ions having a long hydrocarbon chain. In the same vein, the heterodimers [1- hexene···Ag+···1-heptene] and [1- heptene···Ag+···1-octene] dissociate primarily into [Ag+···1-heptene] and [Ag+···1-octene] ions, respectively. Hydrocarbon bidentate formation in [Ag+···1-octene] also reveals itself by the reluctance of this ion to react with water in an ion trap, as opposed to [Ag+···1-hexene] which readily undergoes hydration.
authors.affiliation: Department of Neurology, Laboratory of Neuro-Oncology, Erasmus Medical Center, Rotterdam, 3015 CN, The Netherlands. p.burgers@erasmusmc.nl.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burgers
authors.affiliation: Department of Chemistry and Biological Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: John L
authors.initials: JL
authors.lastname: Holmes
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada L8S 4M1.
authors.forename: Johan K
authors.initials: JK
authors.lastname: Terlouwc