Phenylalkylamines of the general formula C6H5(CH2)nNH2 (n = 1-4) have been delivered to the gas phase as protonated species using electrospray ionization. The ions thus formed have been assayed by IRMPD spectroscopy in two different spectroscopic domains, namely, the 600-1800 and the 3000-3500 cm(-1) regions using either an IR free electron laser or a tabletop OPO/OPA laser source. The interpretation of the experimental spectra is aided by density functional theory calculations of candidate species and vibrational frequency analyses. Protonated benzylamine presents a relatively straightforward instance of a single stable conformer, providing a trial case for the adopted approach. Turning to the higher homologues, C6H5(CH2)nNH3(+) (n = 2-4), more conformations become accessible. For each C6H5(CH2)nNH3(+) ion (n = 2-4), the most stable geometry is characterized by cation-π interactions between the positively charged ammonium group and the aromatic π-electronic system, permitted by the folding of the polymethylene chain. The IRMPD spectra of the sampled ions confirm the presence of the folded structures by comparison with the calculated IR spectra of the various possible conformers. An inspection of the NH stretching region is helpful in this regard.

Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries.

Differential Ion Mobility Spectrometry (DIMS) provides orthogonal separation to mass spectrometry, and DIMS combined with the high sensitivity of a quadrupole ion-trap is shown to be useful for the separation and identification of saccharides. A comprehensive analysis of the separation of anomers (α- and β-methylated glucose) and epimers (α-methylated glucose and mannose) ionized with Li(+), Na(+), and K(+) is performed. DIMS separation is found to be better for saccharides cationized with the two latter species. The corresponding resolving power for the two glucose anomers with Na(+) is found to be very close to the corresponding drift-tube IMS value. The lithiated complexes are investigated further using a combination of infrared spectroscopy integrated to ion-trap mass spectrometry and quantum chemical calculations. Together with DIMS, consistent results are obtained. It is found that two competing structural motifs might be at play, depending on the subtle balance between the maximization of the coordination of the metal cation and the intrinsic conformational energetics of the saccharide, which is for a large part driven by hydrogen bonding. The comparison of simulated and observed spectra clearly shows that a band at ∼3400 cm(-1) is specific to a structural motif found in the lithiated glucose complexes, which could explain the trends observed in the DIMS spectra of the saccharide complexes. It is shown that DIMS-MS/MS using wavelength specific IR activation would provide a new orthogonal dimension to mass spectrometry.

Experiments have been carried out in which electrospray ionization has been used to generate ionic complexes of all-cis 1,2,3,4,5,6 hexafluorocyclohexane. These complexes were subsequently mass isolated in a quadrupole ion trap mass spectrometer and then irradiated by the tunable infrared output of a free electron laser in the 800-1600 cm(-1) range. From the frequency dependence of the fragmentation of the complexes, vibrational signatures of the complexes were obtained. Computational work carried out in parallel reveals that the complexes formed are very strongly bound and are among the most strongly bound complexes of Na(+) and Cl(-) ever observed with molecular species. The dipole moment calculated for the heaxafluorocyclohexane is very large (∼7 D), and it appears that the bonding in each of the complexes has a significant electrostatic contribution.

The structure of a protonated diketopiperazine dipeptide, cyclo-diphenylalanine, is studied by means of infrared multiple photon dissociation spectroscopy combined with quantum chemical calculations. Protonation exclusively occurs on the oxygen site and, in the most stable conformer, results to an intramolecular OH···π interaction, accompanied by a CH···π interaction. Higher-energy conformers with free OH and NH···π interactions are observed as well, due to kinetic trapping. Optimization of the intramolecular interactions involving the aromatic ring dictates the geometry of the benzyl substituents. Changing the chirality of one of the residues has consequences on the CH···π interaction, which is of CH···π nature for LD, while LL shows a CH···π interaction. Higher-energy conformers also display some differences in the nature of the intramolecular interactions.

A combination of infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory calculations is used to investigate the structures and charge-transfer properties of clusters containing transition metals (TM = Co(II), Ni(II), Cu(I), Zn(II), Rh(III), Pd(II), Ag(I), Cd(II)) and the dodecafluorododecaboron dianion, B12F12(2-). In all cases, IRMPD resulted in transfer of electron density to the metal center and production of B12F12(-). Metals that exhibit the highest degree of charge transfer are found to induce reaction among the B12F12 cages, leading to production of BnFm (up to n = m = 24).

Oxidative damage to DNA yields guanine radical cations. Their gas-phase IR spectroscopic signature and acidity have been modelled by the radical cation of 9-methylguanine. Comparisons with quantum chemistry calculations suggest that radical cation formation produces the ground-state keto tautomer, which has an N-H acidity enhanced by ~470 kJ mol(-1).

The radical cation of cytosine (Cyt ) is generated by dissociative oxidation from a ternary Cu complex in the gas phase. The radical cation is characterized by infrared multiple photon dissociation (IRMPD) spectroscopy in the fingerprint region, UV/Vis photodissociation (UVPD) spectroscopy, ion-molecule reactions, and theoretical calculations (density functional theory and ab initio). The experimental IRMPD spectrum features diagnostic bands for two enol-amino and two keto-amino tautomers of Cyt that are calculated to be among the lowest energy isomers, in agreement with a previous study. Although the UVPD action spectrum can also be matched to a combination of the four lowest energy tautomers, the presence of a nonclassical distonic radical cation cannot be ruled out. Its formation is, however, unlikely due to the high energy of this isomer and the respective ternary Cu complex. Gas-phase ion-molecule reactions showed that Cyt undergoes hydrogen-atom abstraction from 1-propanethiol, radical recombination reactions with nitric oxide, and electron transfer from dimethyl disulfide.