High-resolution electronic spectroscopy of molecular conformers. 3-Hydroxy and 3-deuteroxy benzoic acid esters

Hepworth, P.A.; McCombie, J.; Simons, John P.; Pfanstiel, J. F.; Ribblett, Jason W.; Pratt, David W.

doi:10.1016/0009-2614(95)00263-4

Cited by 16 publications

(15 citation statements)

References 17 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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“…22 Further, the angles of rotation of the TM vectors of cis-and trans-1HN are comparable in magnitude, though opposite in sign. As discussed elsewhere, 27 the difference in signs reflects primarily the difference in the orientation of the oxygen lone pair orbitals in the two conformers. Cis/trans rotation of the OH group rotates the TM vector towards the lone pair electron density on oxygen.…”

Section: ͑2͒mentioning

confidence: 77%

High resolution electronic spectroscopy of 1-aminonaphthalene: S0 and S1 geometries and S1←S0 transition moment orientations

Berden

Meerts

Plusquellic

et al. 1996

The Journal of Chemical Physics

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Fluorescence excitation spectroscopy at both vibrational and rotational resolution has been used to probe the changes in energy, electronic distribution, and geometry that occur when 1-aminonaphthalene ͑1AN͒ absorbs light at ϳ332 nm. The 0 0 0 band of the S 1 ←S 0 transition of 1AN is red shifted by nearly 2000 cm Ϫ1 with respect to the corresponding band of naphthalene. Additionally, it is mainly b-axis polarized, unlike the corresponding bands of naphthalene and other 1-substituted naphthalenes. Thus, 1 L a / 1 L b state reversal occurs on 1-substitution of naphthalene with an NH 2 group. The S 0 state of 1AN is pyramidally distorted at the nitrogen atom. Additionally, the NH 2 group is rotated by ϳ20°about the C-NH 2 bond. Excitation of 1AN to the zero-point vibrational level of its S 1 state reduces the C-NH 2 bond length by ϳ0.2 Å and flattens the NH 2 group along both out-of-plane coordinates. Other vibronic bands in the S 1 ←S 0 transition exhibit significantly different rotational constants, inertial defects, and transition moment orientations. An explanation for these findings is given that is based on the well-known conjugative properties of the NH 2 group in chemically related systems.

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“…Similar results were obtained for MHBA. 4 In this case, the 0-trans conformers actually exhibit positive AA values. Now, isomerization about the C-COOCH, bond rotates the in-plane inertial axes, a and b, with respect to the benzene ring.…”

Section: Methodsmentioning

confidence: 95%

“…Thus, conformer A has A = 1964.5 MHz, conformer B has A" = 2460.8 MHz, conformer C has A" = 1855. 4 MHz, and conformer D has A" = 1518.6 MHz. Analogously, there also are significant differences in their ground-state B" and C" constants.…”

Section: Methodsmentioning

confidence: 99%

High Resolution Electronic Spectroscopy of Molecular Conformers. Methyl‐3‐methoxybenzoic Acid Ester

Ribblett

Sinclair

Pratt

1997

Israel Journal of Chemistry

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Abstract. By combining the techniques of rotationally resolved fluorescence excitation spectroscopy in molecular beams and ab initio quantum mechanics, we have determined the identity of the four conformers that contribute to the S,+S, electronic spectrum of methyl-3-methoxybenzoic acid ester in the gas phase. Each conformer exhibits a unique spectrum. Each conformer also exhibits a differently oriented electronic transition moment (TM) in the molecular frame, for which the distinguishable inertial and electronic contributions also have been determined. The results suggest that the S,+S, TM vectors of all conformers are rotated by relatively large (counterclockwise) angles with respect to the a inertial axes, placing them close to the b axis of a -OCH, substituted benzene, and that the exact values of these angles depend upon the mutual conformations of both attached groups with respect to each other.

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High-resolution electronic spectroscopy of molecular conformers. 3-Hydroxy and 3-deuteroxy benzoic acid esters

Cited by 16 publications

References 17 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

High resolution electronic spectroscopy of 1-aminonaphthalene: S0 and S1 geometries and S1←S0 transition moment orientations

High Resolution Electronic Spectroscopy of Molecular Conformers. Methyl‐3‐methoxybenzoic Acid Ester

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