title: Conformational sensitivity of conjugated poly(ethylene oxide)-poly(amidoamine) molecules to cations adducted upon electrospray ionization - a mass spectrometry, ion mobility and molecular modeling study.
abstract: Tandem mass spectrometry and ion mobility spectrometry experiments were performed on multiply charged molecules formed upon conjugation of a poly(amidoamine) (PAMAM) dendrimer with a poly(ethylene oxide) (PEO) linear polymer to evidence any conformational modification as a function of their charge state (2+ to 4+) and of the adducted cation (H(+)vs Li(+)). Experimental findings were rationalized by molecular dynamics simulations. The G0 PAMAM head-group could accommodate up to three protons, with protonated terminal amine group enclosed in a pseudo 18-crown-6 ring formed by the PEO segment. This particular conformation enabled a hydrogen bond network which allowed long-range proton transfer to occur during collisionally activated dissociation. In contrast, lithium adduction was found to mainly occur onto oxygen atoms of the polyether, each Li(+) cation being coordinated by a 12-crown-4 pseudo structure. As a result, for the studied polymeric segment (Mn=1500gmol(-1)), PEO-PAMAM hybrid molecules exhibited a more expanded shape when adducted to lithium as compared to proton.
authors.affiliation: Aix-Marseille Université - CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille, France.
authors.forename: Aura
authors.initials: A
authors.lastname: Tintaru
authors.affiliation: Aix-Marseille Université - CNRS, FR 1739, Fédération des Sciences Chimiques de Marseille, Spectropole, Marseille, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chendo
authors.affiliation: Aix-Marseille Université - CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille, France.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Aix-Marseille Université - CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Viel
authors.affiliation: Aix-Marseille Université - CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Quéléver
authors.affiliation: Aix-Marseille Université - CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille, France.
authors.forename: Ling
authors.initials: L
authors.lastname: Peng
authors.affiliation: University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste, Italy; National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Posocco
authors.affiliation: University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste, Italy; National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste, Italy. Electronic address: sabrina.pricl@di3.units.it.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pricl
authors.affiliation: Aix-Marseille Université - CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille, France. Electronic address: laurence.charles@univ-amu.fr.
authors.forename: Laurence
authors.initials: L
authors.lastname: Charles
mesh_terms: D002412:Cations / Q000737:chemistry; D043844:Crown Ethers / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D011073:Polyamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D002412:Cations; D043844:Crown Ethers; C531249:Poly(amidoamine); D011073:Polyamines; D011092:Polyethylene Glycols; C015762:18-crown-6; D008094:Lithium; C557123:12-crown-4
keywords: Conformation; Ion mobility; Molecular modeling; Poly(amidoamine) dendrimer; Poly(ethylene oxide); Tandem mass spectrometry