Laser-induced fluorescence spectroscopy of ethyl and methyl p-aminobenzoates weakly bound complexes with polar solvents (CH2F2, CH3F and CHF3)

Pereira, R.; Calvo, T.; Castaño, Fernando; Martínez, Marta Gil

doi:10.1016/0301-0104(95)00256-1

Cited by 12 publications

(9 citation statements)

References 46 publications

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“…As in MAB/water complexes, no 1:2 discrete spectra is observed, in spite of the large wavelength range scanned. The bare molecule spectrum exhibit the two 0 0 0 transitions characteristic of the EAB conformers, separated by ϳ10 cm Ϫ1 , in good agreement with previous observations, [14][15][16][17][18] and where the bands at 34 128 and 34 138 cm Ϫ1 were assigned to the EAB trans and the EAB gauche origin bands, respectively.…”

Section: Eab(h 2 O) 1 Complexsupporting

confidence: 83%

A theoretical and experimental study of the ethyl-p-aminobenzoate (H2O)n (n=1–4) complexes

Fernández

Longarte

Unamuno

et al. 2000

The Journal of Chemical Physics

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Weakly bound hydrogen bonded ethyl-p-aminobenzoate/water complexes, referred to henceforth both as EAB/͑H 2 O) n (nϭ1 -4) or by their stoichiometry 1:n, have been investigated with a combined approach of mass and light detector laser spectroscopic techniques and ab initio calculations. The experimental studies follow explorations with laser induced fluorescence ͑LIF͒, and include one-color resonant enhanced multiphoton ionization ͑REMPI͒, two-color REMPI ͑R2PI͒, pressure dependent R2PI and hole burning ͑HB͒ spectroscopies. Calculations were conducted at the B3LYP/6-31ϩG* level and for the 1:1 complex led to the existence of six stable isomers, identified as the experimental origin bands at ϩ4, ϩ6, ϩ13, ϩ89, ϩ96, and ϩ108 cm Ϫ1 above the bare EAB 0 0 0 transition. It has been shown that three of these bands originate in the EAB trans conformer, while the other three derive from the EAB gauche conformer. None of the experimental methods used lead us to observe the EAB͑H 2 O͒ 2 complex spectrum and the inspection of the EAB͑H 2 O͒ 3 REMPI and R2PI spectra has been shown to be a fragmentation from the EAB͑H 2 O͒ 4 complex. The structures and identification of the set of isomers are reported and a comparison with the results on the family complexes methyl-p-aminobenzoate/water is discussed.

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Section: Eab(h 2 O) 1 Complexsupporting

confidence: 83%

A theoretical and experimental study of the ethyl-p-aminobenzoate (H2O)n (n=1–4) complexes

Fernández

Longarte

Unamuno

et al. 2000

The Journal of Chemical Physics

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“…These structures are reminiscent of those found for benzene and toluene solvated by ethane. 1,31 The calculated shift for this cluster is roughly structure independent and is about three times larger than that observed. One possible reason for this lack of agreement for the calculated and experimental shifts is that, for this large solvent molecule, the hydrogen atoms of cpd can no longer be considered unaffected by the electronic excitation ͑see Fig.…”

Section: Cncpd"c 2 F 6 …mentioning

confidence: 53%

“…21 Additionally, the Franck-Condon factors for the cluster vibrational structure strongly suggest that the ground and excited state structures are similar, and that the major change in potential upon D 0 to D 1 excitation is along the z and y directions ͑see Table I͒. The calculated ground state cluster structures are not at all surprising in light of those calculated and determined for the benzyl radical and aromatic molecule clusters found in the literature. 1,2,16,19 One even expects the two structures for Xcpd͑C 2 F 6 ͒ 1 , based on previously reported aromatic-C 2 H 6 cluster structures. 1,31 In the case of C 6 H 5 X͑C 2 H 6 ͒ 1 , however, both structures are observed in the supersonic expansion.…”

Section: B Cluster Structuresmentioning

confidence: 95%

“…1,2,16,19 One even expects the two structures for Xcpd͑C 2 F 6 ͒ 1 , based on previously reported aromatic-C 2 H 6 cluster structures. 1,31 In the case of C 6 H 5 X͑C 2 H 6 ͒ 1 , however, both structures are observed in the supersonic expansion. For Xcpd͑C 2 F 6 ͒ 1 , HB spectra make clear that only one isomer ͑presumed to be the lower energy isomer 1͒ is detected for all Xcpd clusters.…”

Section: B Cluster Structuresmentioning

confidence: 95%

“…A great deal of experience has been accumulated in the last two decades with regard to calculation of these experimental observables based on semiempirical potential energy surfaces for clusters of an aromatic chromophore molecule 1,2,19 solvated by both polar and nonpolar solvent molecules. For example, benzene-rare gas, CH 4 , H 2 O, NH 3 , C 2 H 6 2,19 clusters have been studied with regard to structure, binding energy, vdW modes and the calculated results are in good agreement with the experimental data.…”

Section: B Theoreticalmentioning

confidence: 99%

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Solvation of cyclopentadienyl and substituted cyclopentadienyl radicals in small clusters. I. Nonpolar solvents

Fernández

Yao

Bernstein

1999

The Journal of Chemical Physics

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Cyclopentadienyl (cpd), methylcpd (mcpd), fluorocpd (Fcpd), and cyanocpd (CNcpd) are generated photolytically, cooled in a supersonic expansion, and clustered with nonpolar solvents. The solvents employed are Ar, N2, CH4, CF4, and C2F6. These radicals and their clusters are studied by a number of laser spectroscopic techniques: Fluorescence excitation (FE), hole burning (HB), and mass resolved excitation (MRE) spectroscopies, and excited state lifetime studies. The radical D1←D0 transition is observed for these systems: The radical to cluster spectroscopic shifts for the clusters are quite large, typically 4 to 5 times those found for stable aromatic species and other radicals. Calculations of cluster structure are carried out for these systems using parameterized potential energy functions. Cluster geometries are similar for all clusters with the solvent placed over the cpd ring and the center-of-mass of the solvent displaced toward the substituent. The calculated cluster spectroscopic shifts are in reasonable agreement with the observed ones for N2 and CF4 with all radicals, but not for C2F6 with the radicals. The Xcpd/Ar data are sacrificed to generate excited state potential parameters for these systems. CH4 is suggested to react with all but the CNcpd radical and may begin to react even with CNcpd. van der Waals vibrations are calculated for these clusters in the harmonic approximation for both D1 and D0 electronic states; calculated van der Waals vibrational energies are employed to assign major cluster vibronic features in the observed spectra.

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TICT Molecules

Herbich¹,

Brutschy²

2001

Electron Transfer in Chemistry

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Laser-induced fluorescence spectroscopy of ethyl and methyl p-aminobenzoates weakly bound complexes with polar solvents (CH2F2, CH3F and CHF3)

Cited by 12 publications

References 46 publications

A theoretical and experimental study of the ethyl-p-aminobenzoate (H2O)n (n=1–4) complexes

A theoretical and experimental study of the ethyl-p-aminobenzoate (H2O)n (n=1–4) complexes

Solvation of cyclopentadienyl and substituted cyclopentadienyl radicals in small clusters. I. Nonpolar solvents

TICT Molecules

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