title: Contact Ion Pairs on a Protonated Azamacrocycle: the Role of the Anion Basicity.
abstract: A potassium-containing hexaazamacrocyclic dication, [M•H•K](2+), is able to add in the gas phase mono- and dicarboxylate anions as well as inorganic anions by forming the corresponding monocharged adducts, the structure of which markedly depends on the basicity of the anion. With anions, such as acetate or fluoride, the neutral hexaazamacrocycle M acts as an acceptor of monosolvated K(+) ion. With less basic anions, such as trifluoroacetate or chloride, the protonated hexaazamacrocycle [M•H](+) performs the unusual functions of an acceptor of contact K(+)/anion pairs. Graphical Abstract ᅟ.
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Fraschetti
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy.
authors.forename: Antonello
authors.initials: A
authors.lastname: Filippi
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy.
authors.forename: Maria Elisa
authors.initials: ME
authors.lastname: Crestoni
authors.affiliation: Scuola di Scienze e Tecnologie, Divisione Chimica, Università di Camerino, 62032, Camerino (MC), Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Marcantoni
authors.affiliation: Scuola di Scienze e Tecnologie, Divisione Chimica, Università di Camerino, 62032, Camerino (MC), Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Glucini
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Guarcini
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Montagna
authors.affiliation: Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi de L'Aquila, 67100, L'Aquila, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Guidoni
authors.affiliation: Dipartimento di Chimica e Tecnologie del Farmaco, Università La Sapienza, Rome, Italy. maurizio.speranza@uniroma1.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Speranza
mesh_terms: D000085:Acetates / Q000737:chemistry; D000838:Anions / Q000737:chemistry; D001372:Aza Compounds / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D011188:Potassium / Q000737:chemistry; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000085:Acetates; D000838:Anions; D001372:Aza Compounds; D002412:Cations; D002712:Chlorides; D047028:Macrocyclic Compounds; D011522:Protons; D005459:Fluorides; D011188:Potassium
keywords: Ab initio molecular dynamics; Azamacrocycles; Contact ion pairs; ESI-MS; Ion–ion reactions