Anthropogenic debris in three sympatric seal species of the Western Antarctic Peninsula.

Litter pollution is a growing concern, including for Antarctica and the species that inhabit this ecosystem. In this study, we investigated the microplastic contamination in three seal species that inhabit the Western Antarctic Peninsula: crabeater (Lobodon carcinophaga), leopard (Hydrurga leptonyx) and Weddell (Leptonychotes weddellii) seals. Given the worldwide ubiquity of this type of contaminant, including the Southern Ocean, we hypothesized that the three seal species would present anthropogenic debris in their feces.

Spectroscopic and structural studies on phenyl and pentafluorophenyl trifluorothioacetate, and pentafluorophenyl trifluoroacetate, CFC(O)SCH, CFC(O)SCF and CFC(O)OCF.

Phenyl and pentafluorophenyl trifluorothioacetate, CFC(O)SCH and CFC(O)SCF, were prepared by condensation of CFC(O)Cl and the corresponding mercaptan RSH under vacuum conditions. The compounds were isolated and properly characterized by using infrared spectroscopy, UV-Vis, multinuclear NMR spectroscopy techniques and by mass spectrometry. The crystal structures have been determined for both CFC(O)SCH and according to the best of our knowledge the not yet reported in the literature CFC(O)SCF species.

Preparation of FC(S)SF, FC(S)SeF and FC(Se)SeF through matrix photochemical reactions of F with CS, SCSe, and CSe.

The reactions of F with CS, SCSe, and CSe, respectively, were analyzed under matrix conditions by co-deposition of the halogen with the triatomic molecules trapped in argon matrices at cryogenic temperatures. In all cases, after co-deposition, the formation of the respective van der Waals complexes is observed. When each mixture is subsequently irradiated by means of broad-band UV-visible light (200 ≤ ≤ 800 nm), FC(S)SF, fluorothiocarbonylsulfenyl fluoride, FC(S)SeF, fluorothiocarbonylselenyl fluoride and FC(Se)SeF, fluoroselenocarbonylselenyl fluoride are produced, respectively.

Color Source for the First Argentinian Flags.

In this work, a historical controversy of more than 200 years is settled by the study of the oldest preserved Argentinian flag. The results of the present work reinforce the hypothesis of a number of historians who consider it to be the first flag that was originally hoisted on February 27, 1812, on the banks of the Paraná River. The work consists of a study of the original textile.

Valence and Inner Electronic Excitation, Ionization, and Fragmentation of Perfluoropropionic Acid.

The photoexcitation, photoionization, and photofragmentation of gaseous CFCFC(O)OH were studied by means of synchrotron radiation in the valence and inner energy regions. Photofragmentation events were detected from 11.7 eV through formation of COH, CF, and the parent species M.

Spectroscopic and thermal properties of stannadithiane compounds bearing endocyclic ether and lactone groups.

Four related stannadithiane compounds containing different endocyclic functional groups -including ether (1), diether (2), lactone (3), and spirolactone (4)- were prepared. The conformational landscape has been fully determined for the 8-membered representative (compound 1) resulting in a distorted crown form with the butyl chains adopting an extended conformation. The infrared and Raman spectra of stannadithiane species have been measured and interpreted, aided by quantum chemical calculations and potential energy surface analysis.

Preparation and Properties of Chlorosulfuryl Chloroformate, ClC(O)OSOCl.

The novel chlorosulfuryl chloroformate, ClC(O)OSOCl, was prepared by the reaction of CCl and SO. Alternatively, the compound was obtained from the direct insertion reaction of SO to ClC═O. The latter reaction constitutes also a confirmation of the proposed mechanism for the former one.

Disulfuryl Dichloride ClSO OSO Cl: A Conformation and Polymorphism Chameleon.

Disulfuryl dichloride ClSO OSO Cl was characterized by vibrational spectroscopy in the gaseous and liquid phase as well as in the Ar-matrix. By varying the temperature, certain bands could be assigned to several conformers. Gas-phase electron diffraction revealed a dominance of the anti-conformer at ambient temperature.

Photochemical Reaction of OCSe with ClF in Argon Matrix: A Light-Driven Formation of XC(O)SeY (X, Y = F or Cl) Species.

The photochemistry of OCSe with ClF trapped together in argon matrices at cryogenic temperatures has been explored and the first interhalogen representatives of the elusive XC(O)SeY family, namely syn-ClC(O)SeF, anti-ClC(O)SeF, syn-FC(O)SeCl, and anti-FC(O)SeCl, as well as the hitherto triatomic species ClSeF complexed by a CO molecule, were obtained. Both ClC(O)SeF conformers appear to be produced independently by photolysis of the respective precursors; while formation of both FC(O)SeCl structures is ruled by the presence of an angular molecular complex OCSe···Cl-F formed prior to photolysis. This latter photochemical pathway seems to favor the formation of the less stable anti-FC(O)SeCl structure instead of the more stable syn- one.

Electronic structure determination using an assembly of conventional and synchrotron techniques: The case of a xanthate complex.

The electronic properties of the coordination complex nickel (II) bis-n-propylxanthate, Ni(CH(CH)OC(S)S), were studied by a combination of complementary experimental (both laboratory and synchrotron based techniques) and theoretical methods. Energy differences between HOMOs and LUMOs were determined from UV-visible spectroscopy. The assignment of the transitions were performed with the aid of TD-DFT calculations and based in symmetry considerations.

Structural Analysis of Perfluoropropanoyl Fluoride in the Gas, Liquid, and Solid Phases.

The coexistence of two conformers in perfluoropropanoyl fluoride, CF3CF2C(O)F, differing in the CC-CF dihedral angle (gauche 85(10)% and anti 15(10)%), has been determined by means of gas-phase electron diffraction (GED). Quantum-chemical calculations performed at the MP2 and B3LYP approximations and cc-pVTZ basis sets reproduce the experimental values with confidence. By contrast, FTIR spectra give no clear evidence for the anti-conformer in the gas phase.

Structures of Trichloromethyl Thiocyanate, CCl3 SCN, in Gaseous and Crystalline State.

Trichloromethyl thiocyanate, CCl3 SCN, was structurally studied in both the gas and crystal phases by means of gas electron diffraction (GED) and single-crystal X-ray diffraction (XRD), respectively. Both experimental studies and quantum chemical calculations indicate a staggered orientation of the CCl3 group relative to the SCN group. This conclusion is supported by the similarity of the C-SCN bond length to that of the anti-structure of CH2 ClSCN (Berrueta Martínez et al.

Photoelectron Spectroscopy and Ionic Fragmentation of OSeCl2 and Its Analogue OSCl2 under VUV Irradiation.

The electronic structure and the dissociative ionization of selenium oxychloride, OSeCl2, have been investigated in the valence region by using results from both photoelectron spectroscopy (PES) and synchrotron-based photoelectron photoion coincidence (PEPICO) spectra. The PES is assigned with the help of quantum chemical calculations at the outer-valence Green's function (OVGF) and symmetry adapted cluster/configuration interaction (SAC-CI) levels. The first energy ionization is observed at 11.

Photofragmentation Mechanisms of Chlorosulfonyl Isocyanate, ClSO2NCO, Excited with Synchrotron Radiation between 12 and 550 eV.

The unimolecular photofragmentation mechanisms of chlorosulfonyl isocyanate, ClSO2NCO, excited with tunable synchrotron radiation between 12 and 550 eV, were investigated by means of time-of-flight (TOF) coincidence techniques. The main fragmentation mechanism after single ionization, produced by irradiation of an effusive beam of the sample with synchrotron light in the valence electron region, occurs through the breaking of the Cl-S single bond, giving a chloride radical and a SO2NCO(+) fragment. This mechanism contrasts with the one observed for the related FSO2NCO, in which the rupture of the S-N bond originates the FSO2(+) fragment.

The Structure and Conformation of (CH3 )3 CSNO.

The gas-phase molecular structure of (CH3 )3 CSNO was investigated by using electron diffraction, allowing the first experimental geometrical parameters for an S-nitrosothiol species to be elucidated. Depending on the orientation of the -SNO group, two conformers (anti and syn) are identified in the vapor of (CH3 )3 CSNO at room temperature, the syn conformer being less abundant. The conformational landscape is further scrutinized by using vibrational spectroscopy techniques, including gas-phase and matrix-isolation IR spectroscopy, resulting in a contribution of ca.

Photoexcitation, photoionization, and photofragmentantion of CF3CF2CF2C(O)Cl using synchrotron radiation between 13 and 720 eV.

The main inner shell ionization edges of gaseous CF3CF2CF2C(O)Cl, including Cl 2p, C 1s, O 1s, and F 1s, have been measured in Total Ion Yield (TIY) mode by using tunable synchrotron radiation, and several resonance transitions have been assigned with the help of quantum chemical calculations. Interestingly, resonance transitions observed in the C 1s region can be assigned to different carbon atoms in the molecule according to the degree of fluorine substitution. Ionic photofragmentation processes have been studied by time-of-flight mass spectrometry in the Photoelectron-Photoion-Coincidence (PEPICO) and Photoelectron-Photoion-Photoion-Coincidence (PEPIPICO) modes.

Ionic fragmentation mechanisms of 2,2,2-trifluoroethanol following excitation with synchrotron radiation.

Gaseous 2,2,2-trifluoroethanol (TFE) is excited with synchrotron radiation between 10 and 1000 eV and the ejected electrons and positive ions are detected in coincidence. In the valence-electron energy region, the most abundant species is CH2 OH(+) . Other fragments, including ions produced by atomic rearrangements, are also detected; the most abundant are COH(+) , CFH2 (+) and CF2 H2 (+) .

Matrix isolation study of the conformations and photochemistry of S-ethyl fluorothioformate, FC(O)SCH2CH3.

The IR spectra of S-ethyl fluorothioformate, FC(O)SCH2CH3, were recorded in the vapor phase and compared with the Raman spectrum in the liquid state. Additional IR spectra of the compound isolated in argon and nitrogen matrices at ca. 12 K were also recorded.

Conformational properties of ethyl- and 2,2,2-trifluoroethyl thionitrites, (CX₃CH₂SNO, X = H and F).

The simple 2,2,2-trifluoroethyl thionitrite molecule, CF3CH2SNO, has been prepared in good yield for the first time using CF3CH2SH and NOCl in slight excess. The vapor pressure of the red-brown compound CF3CH2SNO follows, in the temperature range between 226 and 268 K, the equation log p = 12.0-3881/T (p/bar, T/K), and its extrapolated boiling point reaches 51 °C.

Electronic properties of FC(O)SCH2CH3. a combined helium(I) photoelectron spectroscopy and synchrotron radiation study.

The valence electronic properties of S-ethyl flouromethanethioate (S-ethyl fluoromethsanethioate), FC(O)SCH2CH3, were investigated by means of He(I) photoelectron spectroscopy in conjunction with the analysis of the photofragmentation products determined by PEPICO (phtoelectron-photoion-coincidence) by using synchrotron radiation in the 11.1-21.6 eV photon energy range.

Dimers of perhaloacetyl cyanides: CClF2C(O)OC(CN)2CClF2 and CF3C(O)OC(CN) 2CF3. preparation, properties, and spectroscopy.

The vapor of the new compound 1,1-dicyano-2-chloro-2,2-difluoroethyl chlorodifluoroacetate, CClF2C(O)OC(CN)2CClF2 and of the known 1,1-dicyano-2,2,2-trifluoroethyl trifluoroacetate, CF3C(O)OC(CN)2CF3, were investigated using vibrational spectroscopy tools. The existence of rotational isomerism was confirmed for CClF2C(O)OC(CN)2CClF2 when the matrix isolated compound was examined in combination with the computational results applying quantum chemical models. From the four conformers gauche-syn-gauche, gauche-syn-anti, syn-syn-anti, syn-syn-gauche (the used nomenclature is with respect to the ϕ(ClC-C(O)), ϕ((O)C-OC), and ϕ(OC-CCl) torsion angles, respectively) predicted for CClF2C(O)OC(CN)2CClF2 the first two forms can be evidenced using Ar-matrix IR spectroscopy, with the first one being the most abundant at room temperature.

Matrix photochemical study and conformational analysis of CH3C(O)NCS and CF3C(O)NCS.

The vapor of acetyl isocyanide, CH3C(O)NCS, and trifluoroacetyl isocyanide, CF3C(O)NCS, were isolated in solid Ar at 15 K. The existence of rotational isomerism was confirmed when the matrixes were irradiated with broad-band UV-vis light (200 ≤ λ ≤ 800 nm) and also by temperature-dependent Ar-matrix IR spectroscopy. The initial spectra showed the vapor of CH3C(O)NCS and CF3C(O)NCS consist of two conformers syn-syn and syn-anti (with the C═O bond syn with respect to the C-H or C-F bond and syn or anti with respect to the N═C double bond).

Electronic properties of fluorosulfonyl isocyanate, FSO2NCO: a photoelectron spectroscopy and synchrotron photoionization study.

The electronic properties of fluorosulfonyl isocyanate, FSO2NCO, were investigated by means of photoelectron spectroscopy and synchrotron based techniques. The first ionization potential occurs at 12.3 eV and was attributed to the ejection of electrons formally located at the π NCO molecular orbital (MO), with a contribution from nonbonding orbitals at the oxygen atoms of the SO2 group.