title: Hydrogen/Chlorine exchange reactions of gaseous carbanions.
abstract: Gas-phase reactions of three typical carbanions CH(2)NO(2)(-), CH(2)CN(-), and CH(2)S(O)CH(3)(-) with the chloromethanes CH(2)Cl(2), CHCl(3), and CCl(4), examined by tandem mass spectrometry, show a novel hydrogen/chlorine exchange reaction. For example, reaction between the nitromethyl anion CH(2)NO(2)(-) and carbon tetrachloride CCl(4) forms the ion CHClNO(2)(-). The suggested reaction mechanism involves nucleophilic attack by CH(2)NO(2)(-) at the chlorine of CCl(4) followed by proton transfer within the resulting complex [CH(2)ClNO(2) + CCl(3)(-)] to form CHClNO(2)(-) and CHCl(3). Two other carbanions CH(2)CN(-) and CH(2)S(O)CH(3)(-) also undergo the novel hydrogen/chlorine exchange reactions with CCl(4) but to a much smaller extent, their higher nucleophilicities favoring competitive nucleophilic attack reactions. Proton abstraction is the exclusive pathway in the reactions of these carbanions with CHCl(3). While CH(2)CN(-) and CH(2)S(O)CH(3)(-) promote mainly proton abstraction and nucleophilic displacement in reactions with CH(2)Cl(2), CH(2)NO(2)(-) does not react.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Meurer
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin
mesh_terms: D000838:Anions; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D002713:Chlorine / Q000032:analysis* / Q000737:chemistry*; D005740:Gases / Q000032:analysis / Q000737:chemistry*; D006859:Hydrogen / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000838:Anions; D005740:Gases; D002713:Chlorine; D002244:Carbon; D006859:Hydrogen