Glycine Dimers: Structure, Stability, and Medium Effects

Friant-Michel, Pascale; Ruiz‐López, Manuel F.

doi:10.1002/cphc.201000354

Cited by 41 publications

(56 citation statements)

References 76 publications

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“…For all neutral molecules, the C1 conformer is of the lowestenergy,i nl ine with previous calculations by Chocholoušovµ et al [34] and Friant-Michel and Ruiz-Lopez [35] on glycine dimers. The structure of radicalm onocations after optimization is shown in Figure 3.…”

Section: Resultsoft He Calculationsmentioning

confidence: 56%

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

et al. 2015

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Collisions between O(3+) ions and neutral clusters of amino acids (alanine, valine and glycine) as well as lactic acid are performed in the gas phase, in order to investigate the effect of ionizing radiation on these biologically relevant molecular systems. All monomers and dimers are found to be predominantly protonated, and ab initio quantum-chemical calculations on model systems indicate that for amino acids, this is due to proton transfer within the clusters after ionization. For lactic acid, which has a lower proton affinity than amino acids, a significant non-negligible amount of the radical cation monomer is observed. New fragment-ion channels observed from clusters, as opposed to isolated molecules, are assigned to the statistical dissociation of protonated molecules formed upon ionization of the clusters. These new dissociation channels exhibit strong delayed fragmentation on the microsecond time scale, especially after multiple ionization.

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Section: Resultsoft He Calculationsmentioning

confidence: 56%

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

et al. 2015

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“…ref. [44][45][46]. These studies show that different conformations could present similar stabilization energies, and therefore several conformers of the dimer having different infrared spectra could be present in the gas phase.…”

Section: Polar Environmentsmentioning

confidence: 67%

An infrared study of solid glycine in environments of astrophysical relevance

Maté

Rodrı́guez-Lazcano

Gálvez

et al. 2011

Phys. Chem. Chem. Phys.

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The conversion from neutral to zwitterionic glycine is studied using infrared spectroscopy from the point of view of the interactions of this molecule with polar (water) and non-polar (CO 2 , CH 4 ) surroundings. Such environments could be found on astronomical or astrophysical matter. The samples are prepared by vapour-deposition on a cold substrate (25 K), and then heated up to sublimation temperatures of the co-deposited species. At 25 K, the neutral species is favoured over the zwitterionic form in non-polar environments, whereas for pure glycine, or in glycine/water mixtures, the dominant species is the latter. The conversion is easily followed by the weakening of two infrared bands in the mid-IR region, associated to the neutral structure. Theoretical calculations are performed on crystalline glycine and on molecular glycine, both isolated and surrounded by water. Spectra predicted from these calculations are in reasonable agreement with the experimental spectra, and provide a basis to the assignments. Different spectral features are suggested as probes for the presence of glycine in astrophysical media, depending on its form (neutral or zwitterionic), their temperature and composition.

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“…Obviously, such an approach has already been used (e.g., see Refs. ) and shown to perform adequately even for carboxylic acid oligomers …”

Section: Experiments Methods and Modelsmentioning

confidence: 99%

On the origin and consequences of high DMAEMA reactivity ratio in ATRP copolymerization with MMA: An experimental and theoretical study^#

Mella

Rocca

Miele

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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Designing and tuning a copolymerization process to obtain specific material properties is still fundamentally empirical and requires the determination of apparent reactivity ratios rs. To this end, PEG–(MMA–DMAEMA)n copolymers obtained via ATRP of MMA and DMAEMA using a PEG‐based initiator in toluene were analyzed to extract monomer relative reactivities; the impact of changing solvent on the latter was also tested. Differing from previous free radical and controlled radical copolymerizations (CRcoP), we found that DMAEMA is preferentially included (rMMAnormals=0.36(±10%) and rDMAEMAnormals=2.76(±15%)) in toluene; increasing the solvent polarity decreased the gap between rs. With these data, kMC simulations based on the copolymerization terminal model were used to investigate copolymer microstructure, which is not amenable to NMR investigation. kMC simulations evidenced both a gradient‐like nature of the copolymers and a somewhat unexpected qualitative change in the probability of finding MMA‐rich triads along the chain depending on initial feed composition. An additional DFT analysis suggested the likely formation of a DMAEMA:CuBr:2‐2′‐bipyridine complex, which being involved in the regeneration of reactive radicals from dormant species, is expected to locally increase DMAEMA concentration favoring its addition to the growing chains. The formation of such complex is also supported by 1H‐NMR experiments. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1366–1382

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Glycine Dimers: Structure, Stability, and Medium Effects

Cited by 41 publications

References 76 publications

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

An infrared study of solid glycine in environments of astrophysical relevance

On the origin and consequences of high DMAEMA reactivity ratio in ATRP copolymerization with MMA: An experimental and theoretical study^#

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Glycine Dimers: Structure, Stability, and Medium Effects

Cited by 41 publications

References 76 publications

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

An infrared study of solid glycine in environments of astrophysical relevance

On the origin and consequences of high DMAEMA reactivity ratio in ATRP copolymerization with MMA: An experimental and theoretical study#

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On the origin and consequences of high DMAEMA reactivity ratio in ATRP copolymerization with MMA: An experimental and theoretical study^#