Fragmentation patterns in the gas-phase pyrolysis of some bi- and tri-cyclic sulfolanes related to the 8-thiabicyclo[4.3.0]non-3-ene 8,8-dioxide ring system

1994 ◽  
pp. 2301 ◽  
Author(s):  
R. Alan Aitken ◽  
J. I. G. Cadogan ◽  
Ian Gosney ◽  
Stephen F. Newlands
Keyword(s):  
Gas Phase ◽  
Ring System ◽  
Fragmentation Patterns

Ring inversion in solid fluorocyclohexane

1986 ◽  
Vol 64 (10) ◽  
pp. 2094-2095 ◽  
Author(s):  
Roderick E. Wasylishen
Keyword(s):  
Solid State ◽  
Gas Phase ◽  
Solid Phase ◽  
Ring System ◽  
Cyclohexane Ring ◽  
Ring Inversion ◽  
Nmr Study

Inversion of the cyclohexane ring system in the solid state has been directly observed in a 19F nmr study of solid fluorocyclohexane. The barrier to ring inversion in the orientationally disordered solid phase, ΔG≠e→a = 44.1 ± 0.9 kJ mol−1 at 263 K is found to be only slightly larger than the value previously reported for a CFCl3 solution of fluorocyclohexane. The population of the equatorial conformation is slightly favored over the axial conformation with K = Pe/Pa = 1.56 at 281 K; similar values have been obtained in CFCl3 and in the gas phase.

Gas-Phase Reactivity of Copper Cations with Ketones

2001 ◽  
Vol 7 (4-5) ◽  
pp. 313-320 ◽  
Author(s):  
P. Fordham ◽  
M. Deschasse ◽  
V. Haldys ◽  
J. Tortajada ◽  
J.-P. Morizur
Keyword(s):  
Gas Phase ◽  
Copper Ions ◽  
Ion Molecule Reactions ◽  
Fragmentation Mechanisms ◽  
Dehydration Reactions ◽  
Ion Kinetic Energy ◽  
The Rich ◽  
Fragmentation Patterns ◽  
Gas Phase Ion ◽  
Chemical Ionisation

Gas-phase ion–molecule reactions between copper ions and ketones were investigated. Organometallic adducts were prepared using a chemical ionisation/fast-atom bombardment source. Abundant pseudo-molecular ion adducts were observed in the Cu+-chemical ionisation mass spectra and their unimolecular decompositions were studied by tandem mass spectrometry. Mass-analysed ion kinetic energy spectroscopy revealed diagnostic fragmentation patterns. Losses of alkenes, losses of alkanes and dehydrogenation and dehydration reactions were observed, as well as eliminations of CuR (R = C nH2 n + 1). The rich reaction chemistry of the cationised ketones enabled differentiation of the majority of the linear and branched ketone isomers studied. Isotope-labelled derivatives were employed to elucidate fragmentation mechanisms.

scholarly journals Time-dependent density functional theory molecular dynamics simulation of doubly charged uracil in gas phase

Open Physics ◽  
2014 ◽  
Vol 12 (2) ◽  
Author(s):  
Pablo López-Tarifa ◽  
Marie-Anne Hervé du Penhoat ◽  
Rodophe Vuilleumier ◽  
Marie-Pierre Gaigeot ◽  
Ursula Rothlisberger ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Time Dependent ◽  
Dynamics Simulation ◽  
Functional Theory ◽  
Fragmentation Patterns ◽  
Doubly Charged ◽  
Dependent Density

AbstractWe use time-dependent density functional theory and Born-Oppenheimer molecular dynamics methods to investigate the fragmentation of doubly ionized uracil in gas phase. Different initial electronic excited states of the dication are obtained by removing electrons from different inner-shell orbitals of the neutral species. We show that shape-equivalent orbitals lead to very different fragmentation patterns revealing the importance of the intramolecular chemical environment. The results are in good agreement with ionion coincidence measurements of uracil collision with 100 keV protons.

scholarly journals UV photodissociation spectroscopy of cryogenically cooled gas phase host–guest complex ions of crown ethers

2015 ◽  
Vol 17 (39) ◽  
pp. 25925-25934 ◽  
Author(s):  
Yoshiya Inokuchi ◽  
Takeharu Haino ◽  
Ryo Sekiya ◽  
Fumiya Morishima ◽  
Claude Dedonder ◽  
...  
Keyword(s):  
Gas Phase ◽  
Crown Ethers ◽  
Electronic Spectra ◽  
Complex Ions ◽  
Guest Complex ◽  
Dramatic Effect ◽  
Host Guest Complex ◽  
Guest Species ◽  
Fragmentation Patterns

Crown ethers show a dramatic effect on the electronic spectra and fragmentation patterns of guest species.

scholarly journals Laser production of gas phase complexes of metalα-aminophosphonic acid mixtures and their role in chiral recognition

2001 ◽  
Vol 3 (4) ◽  
pp. 217-221 ◽  
Author(s):  
A. Paladini ◽  
C. Calcagni ◽  
T. Di. Palma ◽  
M. Satta ◽  
M. Speranza ◽  
...  
Keyword(s):  
Gas Phase ◽  
Phosphonic Acid ◽  
Chiral Recognition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Collision Induced Dissociation ◽  
Spectral Features ◽  
Aminophosphonic Acid ◽  
Aminophosphonic Acids ◽  
Fragmentation Patterns

Clusters between first-group metal ions and chiralα-aminophosphonic acids have been readily generated by Pulsed Laser Ablation (PLA) and by Electrospray Ionization (ESI) and their fragmentation investigated by mass spectrometry. The complexes studied have the general formula[Me(I)Cl2]+, where Me(I) is H, Li, Na, or K, C is (R)-(—)-(1-aminoethyl) phosphonic acid(ER)and (S)-(+)-(1-aminoethyl) phosphonic acid(ES),(1R)-(+)-(1-amino-2-methylpropyl) phosphonic acid(PR)and (1S)-(—)-(1-amino-2-methylpropyl) phosphonic acid(PS),(1R)-(-)-(1-amino-hexyl) phosphonic acid (HR) and (1S)-(+)-(1-amino-hexyl) phosphonic acid (HS), o-phospho-L-serine (SS)ando-phospho-D-serine(SR), and L is a referenceα-aminophosphonic acid (E, P, H or S) of defined configuration. Collision induced dissociation (CID) of diastereomeric[Me(I)Cl2]+complexes leads to fragmentation patterns characterized by[Me(I)Cl]+/[Me(I)L2]+abundance ratios which depend upon the configuration of solute C. These different spectral features were correlated to the different stability of the diastereomeric[Me(I)CRL]+and[Me(I)CSL]+complexes in the gas phase.

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