FT-ICR studies of gas-phase ionic nitration of benzene: the role of electron- and proton-transfer processes

1992 ◽  
Vol 117 ◽  
pp. 37-46 ◽  
Author(s):  
M. Attinà ◽  
F. Cacace ◽  
M. Speranza
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Transfer Processes ◽  
Ft Icr

The exemplary role of nanoconfinement in the proton transfer from acids to ammonia

2017 ◽  
Vol 19 (30) ◽  
pp. 19869-19872 ◽  
Author(s):  
Manoj K. Tripathy ◽  
K. R. S. Chandrakumar
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Barrier Crossing ◽  
Reaction Barrier ◽  
Transfer Processes ◽  
Mineral Acids

Proton transfer processes from mineral acids to bases are normally feasible in solution and they cannot spontaneously occur in the gas phase. Our results demonstrate that the remarkable aspect of reaction barrier crossing can be achieved by confining these systems in a suitable size of a nanocavity.

Effects of Crystal Packing on Photoinduced Proton-Transfer Processes of 2,4-Dinitrobenzylpyridine Derivatives

1997 ◽  
Vol 53 (2) ◽  
pp. 306-316 ◽  
Author(s):  
S. Khatib ◽  
M. Botoshansky ◽  
Y. Eichen
Keyword(s):  
Proton Transfer ◽  
Crystal Packing ◽  
Aromatic Rings ◽  
Proton Abstraction ◽  
Thermally Activated ◽  
Transfer Processes ◽  
Highly Sensitive ◽  
Photoinduced Proton Transfer ◽  
Photochemical Properties

Photoinduced and thermally activated proton-transfer processes taking place in crystals of 2-(2,4-dinitrobenzyl)pyridine and some of its derivatives are highly sensitive to molecular packing. Small differences in the way the molecules are packed in the crystal are found to dominate molecular properties in controlling the photoactivity of the different phototautomers, leading, for example, to photoactive or photoinert systems. Three compounds, 2-(2,4-dinitrobenzyl)-4-methylpyridine, 1-(2,4-dinitrophenyl)-l-(2-pyridine)ethane and 4′-(2,4-dinitrobenzyl)-4-methyl-2,2′-bipyridine, having different photochemical properties, were prepared and their crystal structures characterized by means of X-ray analysis. In the photoinert crystals the 2,4-dinitrophenyl group is π-stacked with other aromatic rings of neighboring molecules. This arrangement may open some deactivation channels to the excited state which are faster than the proton-transfer process, leading to photoinert crystals. The absence of π-stacking between the chromophore and other aromatic rings leads to photoactive systems. An O atom of the o-nitro group is the only basic atom that is systematically found to interact with the abstracted proton. It seems that this atom is responsible for the photoinduced proton abstraction of the benzylic H atom, while the role of the N atom of the pyridine ring in the proton-abstraction process is mainly inductive.

Gas-Phase Basicity of Formaldehyde by the Thermokinetic Method

2000 ◽  
Vol 6 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Guy Bouchoux ◽  
Danielle Leblanc
Keyword(s):  
Fourier Transform ◽  
Proton Transfer ◽  
Equilibrium Constant ◽  
Gas Phase ◽  
Cyclotron Resonance ◽  
Transfer Reactions ◽  
Ion Cyclotron Resonance ◽  
Proton Transfer Reactions ◽  
Ft Icr

A series of proton transfer reactions monitored in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer allows the determination of the gas-phase basicity ( GB) and the proton affinity ( PA) of formaldehyde. The values determined by the thermokinetic method, GB(CH2O) = 681.5 ± 0.7 kJ mol−1 and PA(CH2O) = 711.5 ± 2.1 kJ mol−1 are in excellent agreement with data originating from proton transfer equilibrium constant determinations or from G2 calculations.

scholarly journals PROTON TRANSFER IN PHOSPHORUS-CONTAINING ACID–N,N-DIMETHYLFORMAMIDE SYSTEM WITH GLANCE OF ENVIRONMENT

2018 ◽  
Vol 59 (6) ◽  
pp. 37
Author(s):  
Lyubov P. Safonova ◽  
Irina V. Fedorova ◽  
Michael A. Krestyaninov
Keyword(s):  
Proton Transfer ◽  
Solvent Effect ◽  
Gas Phase ◽  
Energy Barrier ◽  
Continuum Model ◽  
Energy Surface ◽  
Molecular Complexes ◽  
Transfer Processes ◽  
Polarized Continuum Model ◽  
Phosphorus Containing

Proton transfer processes in the molecular and ion-molecular complexes of phosphorus acids (phosphoric H3PO4, phosphorous H3PO3, methylphosphonic СН3Н2РО3) with N,N-dimethylformamide (DMF) was studied. The potential energy surface (PES) for proton transfer was studied using the B3LYP/6-31++G(d,p) level of theory, and the solvent effect (here DMF) on the PES was included using the conductor polarized continuum model (CPCM). For all cases, the energy profile for proton transfer represents a double well curve, if intermolecular O…Odistance for the hydrogen bond considered has a fixed length equal to 2.7 Å. The solvent effect favors a proton transfer in the molecular complexes, but no shift of the equilibrium towards ionic pairs is observed. As a result, the energy values associated with proton transfer are significantly reduced in comparison with those found for the gas phase. The proton transfer in the complexes of H3PO4 with DMF is more favored than this process for the cases with H3PO3 and СН3Н2РО3. The probability of proton transfer in the Н3РО4–DMF and (Н3РО4)2–DMF is nearly identical. On the contrary, the barrier height for transfer in Н3РО4–(DMF)n for n=1÷3 increases with increasing number of DMF molecules. The energy barrier for proton transfer in the DMFH+–DMF and H3PO4–H2PO4– is lower than the ones for the molecular complexes.

Application of experimental (FT-ICR) and theoretical (AM1) methods to the study of proton-transfer reactions for tautomerizing amidines in the gas phase

1996 ◽  
Vol 355 (3-4) ◽  
pp. 412-414 ◽  
Author(s):  
R. W. Taft ◽  
E. D. Raczynska ◽  
P. -C. Maria ◽  
I. Leito ◽  
W. Lewandowski ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Transfer Reactions ◽  
Proton Transfer Reactions ◽  
Ft Icr
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