Effect of the intermolecular hydrogen bond conformation on the structure and reactivity of the p-cresol(H2O)(NH3) van der Waals complex

Oldani, Andrés N.; Ferrero, Juan C.; Pino, Gustavo A.

doi:10.1039/b916901f

Cited by 15 publications

(25 citation statements)

References 44 publications

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“…The experimental set-up used in Córdoba for LIF and REMPI spectroscopy with nanosecond lasers has been described previously. 42 For the pump-probe experiments, the third harmonic (355 nm) output of a mode-locked picoseconds Nd:YAG laser (EKSPLA-SL300) was split in two parts to pump two OPA and SHG systems (EKSPLA-PG411) for obtaining tunable UV light. One of the systems was used as excitation laser tuned at several frequencies ( 1 ) while the other system was tuned to 325 nm and used as ionization laser ( 2 ), keeping its energy at 100 J/pulse approximately, while the energy of the  1 laser was attenuated to preclude one-color two-photon ionization.…”

Section: Methodsmentioning

confidence: 99%

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Hydrogen bonds vs. π-stacking interactions in the p-aminophenol⋯p-cresol dimer: an experimental and theoretical study

Capello

Hernández

Broquier

et al. 2016

Phys. Chem. Chem. Phys.

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The gas phase structure and excited state lifetime of the p-aminophenolp-cresol heterodimer have been investigated by REMPI and LIF spectroscopy with nanosecond laser pulses and pump-probe experiments with picosecond laser pulses as a model system to study the competition between π-π and H-bonding interactions in aromatic dimers. The excitation is a broad and unstructured band. The excited state of the heterodimer is long lived (2.5 ± 0.5) ns with a very broad fluorescence spectrum red-shifted by 4000 cm with respect to the excitation spectrum. Calculations at the MP2/RI-CC2 and DFT-ωB97X-D levels indicate that hydrogen-bonded (HB) and π-stacked isomers are almost isoenergetic in the ground state while in the excited state only the π-stacked isomer exists. This suggests that the HB isomer cannot be excited due to negligible Franck-Condon factors and therefore the excitation spectrum is associated with the π-stacked isomer that reaches vibrationally excited states in the S state upon vertical excitation. The excited state structure is an exciplex responsible for the fluorescence of the complex. Finally, a comparison was performed between the π-stacked structure observed for the p-aminophenolp-cresol heterodimer and the HB structure reported for the (p-cresol) homodimer indicating that the differences are due to different optical properties (oscillator strengths and Franck-Condon factors) of the isomers of both dimers and not to the interactions involved in the ground state.

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Section: Methodsmentioning

confidence: 99%

“…The experimental set-up used in Córdoba for LIF and REMPI spectroscopy with nanosecond lasers has been described previously. 42 Briefly, the carrier gas He at 1. The ions were extracted perpendicularly to the molecular beam and laser directions, and detected by a microchannel plate (Jordan MCP).…”

Section: Methodsmentioning

confidence: 99%

Hydrogen bonds vs. π-stacking interactions in the p-aminophenol⋯p-cresol dimer: an experimental and theoretical study

Capello

Hernández

Broquier

et al. 2016

Phys. Chem. Chem. Phys.

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“…The setup used in Córdoba for LIF and REMPI spectroscopy with nanosecond lasers were essentially the same as described previously, 42 and the experimental conditions were the same as for the experiments performed in Orsay. The LIF and REMPI spectra were measured using a frequency doubled Lumonics (HD5000) dye laser (FWHM = 5 ns) operating with a mixture of Rhodamine 590 and 610, pumped by the second harmonic of a Spectra-Physics (Indi-HG) Nd:YAG laser.…”

Section: Methodsmentioning

confidence: 99%

Fast excited state dynamics in the isolated 7-azaindole-phenol H-bonded complex

Capello

Broquier

Dedonder‐Lardeux

et al. 2013

The Journal of Chemical Physics

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The excited state dynamics of the H-bonded 7-azaindole-phenol complex (7AI-PhOH) has been studied by combination of picosecond pump and probe experiments, LIF measurements on the nanosecond time scale and ab initio calculations. A very short S(1) excited state lifetime (30 ps) has been measured for the complex upon excitation of the 0(0)(0) transition and the lifetime remains unchanged when the ν(6) vibrational mode (0(0)(0) + 127 cm(-1)) is excited. In addition, no UV-visible fluorescence was observed by exciting the complex with nanosecond pulses. Two possible deactivation channels have been investigated by ab initio calculations: first an excited state tautomerization assisted by a concerted double proton transfer (CDPT) and second an excited state concerted proton electron transfer (CPET) that leads to the formation of a radical pair (hydrogenated 7AIH(●) radical and phenoxy PhO(●) radical). Both channels, CDPT and CPET, seem to be opened according to the ab initio calculations. However, the analysis of the ensemble of experimental and theoretical evidence indicates that the excited state tautomerization assisted by CDPT is quite unlikely to be responsible for the fast S(1) state deactivation. In contrast, the CPET mechanism is suggested to be the non-radiative process deactivating the S(1) state of the complex. In this mechanism, the lengthening of the OH distance of the PhOH molecule induces an electron transfer from PhOH to 7AI that is followed by a proton transfer in the same kinetic step. This process leads to the formation of the radical pair (7AIH(●)···PhO(●)) in the electronically excited state through a very low barrier or to the ion pair (7AIH(+)···PhO(-)) in the ground state. Moreover, it should be noted that, according to the calculations the πσ* state, which is responsible for the H loss in the free PhOH molecule, does not seem to be involved at all in the quenching process of the 7AI-PhOH complex.

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“…The experimental apparatus was previously described 27,28 and only the main changes will be mentioned here. Briefly, it consists of two differentially pumped chambers that contain a cluster source and a time-of-flight mass spectrometer (TOF-MS).…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Unexpected size distribution of Ba(H2O)n clusters: why is the intensity of the Ba(H2O)1 cluster anomalously low?

Cabanillas-Vidosa

Rossa

Pino

et al. 2011

Phys. Chem. Chem. Phys.

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An experimental and theoretical study on the reactivity of neutral Ba atoms with water clusters has been conducted to unravel the origin of the irregular intensity pattern observed in one-photon ionization mass spectra of a Ba(H(2)O)(n)/BaOH(H(2)O)(n-1) (n = 1-4) cluster distribution, which was generated in a laser vaporization-supersonic expansion source. The most remarkable irregular feature is the finding for n = 1 of a lower intensity for the Ba(+)(H(2)O)(n) peak with respect to that of BaOH(+)(H(2)O)(n-1), which is opposite to the trend for n = 2-4. Rationalization of the data required consideration of a distinct behavior of ground-state and electronically excited state Ba atoms in inelastic and reactive Ba + (H(2)O)(n) encounters that can occur in the cluster source. Within this picture, the generation of Ba(H(2)O)(n) (n > 1) association products results from stabilizing collisions with atoms of the carrier gas, which are favored by intramolecular vibrational redistribution that operates on the corresponding collision intermediates prior to stabilization; the latter is unlikely to occur for Ba + (H(2)O) encounters. Overall, this interpretation is consistent with additional in-source laser excitation and quenching experiments, which aimed to explore qualitatively the effect of perturbing the Ba atom electronic state population distribution on the observed intensity pattern, as well as with the energetics of various possible reactions for the Ba + H(2)O system that derive from high level ab initio calculations.

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Effect of the intermolecular hydrogen bond conformation on the structure and reactivity of the p-cresol(H2O)(NH3) van der Waals complex

Cited by 15 publications

References 44 publications

Hydrogen bonds vs. π-stacking interactions in the p-aminophenol⋯p-cresol dimer: an experimental and theoretical study

Hydrogen bonds vs. π-stacking interactions in the p-aminophenol⋯p-cresol dimer: an experimental and theoretical study

Fast excited state dynamics in the isolated 7-azaindole-phenol H-bonded complex

Unexpected size distribution of Ba(H2O)n clusters: why is the intensity of the Ba(H2O)1 cluster anomalously low?

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