title: Ethylenediamine as a liquid chemical reagent to probe hydrogen bonding and host-guest interactions with crown ethers in an ion trap tandem mass spectrometer.
abstract: Ethylenediamine (EDA) was used as a novel liquid chemical reagent to probe hydrogen bonding and host-guest interactions with crown ether derivatives in an ion trap mass spectrometer (ITMS). Selective ion/molecule reaction product ions were generated by reactions of EDA with oxygenated and aza-crown ethers. For the oxygenated crown ethers, glycols and dimethylglycols, ion/molecule reactions led to the formation of the protonated molecules ([M+H](+)) and adduct ions including [M+30](+), [M+44](+) and [M+61](+). The aza-crown ethers produced [M+H](+), [M+13](+) and [M+27](+) ions. Collisionally activated dissociation (CAD) experiments were applied to probe the binding strength of these ion/molecule reaction products. CAD results indicated that all these hydrogen-bonding complexes are weakly bound except for the [M+44](+) ion of 18-crown-6, since all the complexes dissociate to the protonated polyether and/or protonated EDA. Fragmentation of the [M+H](+) ions under CAD conditions indicates the extensive covalent bond cleavage of the protonated crown ether skeleton.
authors.affiliation: Department of Chemistry, Tamkang University, Tamsui, Taipei Hsien, 251, Taiwan.
authors.forename: Hui-Fen
authors.initials: HF
authors.lastname: Wu
authors.forename: Pei-Yi
authors.initials: PY
authors.lastname: Lin
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D043844:Crown Ethers / Q000737:chemistry*; D005029:Ethylenediamines / Q000737:chemistry*; D006860:Hydrogen Bonding; D007202:Indicators and Reagents; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D043844:Crown Ethers; D005029:Ethylenediamines; D007202:Indicators and Reagents; C031234:ethylenediamine