Zum System Essigsäure-Trifluoressigsäure: Bildung und Kristallstruktur eines über zwei sehr ungleiche Wasserstoffbrücken cyclisch-heterodimeren 1:1-Addukts

Schilling, Michaela; Bartmann, K.; Mootz, D.

doi:10.1016/0022-1139(94)03217-n

Cited by 4 publications

(12 citation statements)

References 16 publications

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“…In the crystal, the acetic acid-Tfa bimolecule contains intermolecular distances that differ even more than those calculated for FA-Tfa. 38 These are 2.761 ( 0.005 Å on the acetic acid OH side, and 2.571 ( 0.004 Å on the Tfa OH side, compared to the analogous FA-Tfa distances of 2.704 Å and 2.620 Å. The greater difference in the acetic acid-Tfa O‚‚‚O distances is consistent with the stronger hydrogen bond interactions in this complex compared to FA-Tfa.…”

Section: Resultsmentioning

confidence: 54%

“…In the crystal, the acetic acid−Tfa bimolecule contains intermolecular distances that differ even more than those calculated for FA−Tfa . These are 2.761 ± 0.005 Å on the acetic acid OH side, and 2.571 ± 0.004 Å on the Tfa OH side, compared to the analogous FA−Tfa distances of 2.704 Å and 2.620 Å.…”

Section: Resultsmentioning

confidence: 70%

“…In the crystal environment, the acetic acid-Tfa bimolecule does have such an unsymmetrical structure. 38 In this report, gas-phase spectroscopic and computational data are presented that demonstrate unequal proton donation along the hydrogen bonds, resulting in a highly polar and unsymmetrical complex.…”

Section: Introductionmentioning

confidence: 95%

“…37 The structure of the acetic acid-trifluoroacetic acid (Tfa) bimolecule, which crystallizes from the mixed acids at low temperatures, has been determined. 38 Theoretical studies of carboxylic acid bimolecules have been limited to semiempirical calculations of complexation energy and overall geometry of the FA-Tfa 21 and acetic acid-Tfa 39 bimolecules. No ab initio or DFT calculations have been reported for carboxylic acid bimolecules.…”

Section: Introductionmentioning

confidence: 99%

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The Formic Acid−Trifluoroacetic Acid Bimolecule. Gas-Phase Infrared Spectrum and Computational Studies

Keller

2004

J. Phys. Chem. A

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The gas-phase FT-IR spectrum of the formic acid−trifluoroacetic acid (FA−Tfa) hydrogen-bonded complex, or bimolecule, was obtained by numerical analysis of the FT-IR spectrum of a mixture of FA and Tfa vapors. Nineteen out of 24 vibrational modes predicted by ab initio frequency calculations to occur in the mid-IR range (400−4000 cm-1) were observed as well-defined absorbance peaks, with the other five occurring as complex or overlapped regions. Several hydrogen-bond-influenced vibrations of each monomer were identified, including CO stretching and COH in-plane and OH out-of-plane bending. These occurred at 1701, 1403, and 871 cm-1, respectively, for FA, and at 1774, 1325, and 942 cm-1, respectively, for Tfa. The hydrogen bond donated by Tfa in the bimolecule appears to be stronger than that in the Tfa dimer, while the FA-donated hydrogen bond is weaker than that in the FA dimer. Geometry optimization and vibrational frequency calculations were carried out at 21 levels of theory up to B3LYP/aug-cc-PVDZ. All levels of theory predicted an unsymmetrical complex, with hydrogen bond distances of 1.608 Å and 1.706 Å donated by Tfa and FA, respectively, and the corresponding O···O distances of 2.620 Å and 2.704 Å (B3LYP/aug-cc-PVDZ). These values differ from the symmetrical, or nearly symmetrical, structure derived from microwave spectra (Costain and Srivastava, J. Chem. Phys. 1964, 41, 1620−1627; Martinache et al. Chem. Phys. 1990, 148, 129−140). In agreement with previous experimental findings, the bimolecule was predicted to be more stable than either homodimer, with a calculated ΔH complexation of −14.2 kcal/mol (B3LYP/aug-cc-PVDZ). Mulliken population analysis predicted a polar complex with a transfer of 0.02−0.03 protons from Tfa to FA and a predicted dipole moment of 2.3−2.4 D, depending on the level of theory. The combined spectroscopic and computational evidence indicates that in this complex the Tfa-donated hydrogen bond is strengthened more than the FA-donated hydrogen bond is weakened.

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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The Formic Acid−Trifluoroacetic Acid Bimolecule. Gas-Phase Infrared Spectrum and Computational Studies

Keller

2004

J. Phys. Chem. A

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“…The bases selected m•e charged as well as uncharged, like cesium and tetramethylammonium hydroxide [2] on one hand and certain new phosphazenes, aliphatic and aromatic amines [3], and the prototype synthetic macrocyclic polyether 18-crown-6 [4] on the other. The acids m•e mainly halogenoacetic ones [5].…”

mentioning

confidence: 99%

Hydrates and hydrogen bonding: crystal chemistry of and with some selected acids and bases

Mootz¹

1996

Acta Cryst Sect A

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Synproportionation reactions between copper(II) trihalogenoacetates Cu(CX3CO2)2, X = F, Cl or Br, and copper in the presence of carbon monoxide

Dell’Amico

Alessio

Calderazzo

et al. 2000

J. Chem. Soc., Dalton Trans.

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Zum System Essigsäure-Trifluoressigsäure: Bildung und Kristallstruktur eines über zwei sehr ungleiche Wasserstoffbrücken cyclisch-heterodimeren 1:1-Addukts

Cited by 4 publications

References 16 publications

The Formic Acid−Trifluoroacetic Acid Bimolecule. Gas-Phase Infrared Spectrum and Computational Studies

The Formic Acid−Trifluoroacetic Acid Bimolecule. Gas-Phase Infrared Spectrum and Computational Studies

Hydrates and hydrogen bonding: crystal chemistry of and with some selected acids and bases

Synproportionation reactions between copper(II) trihalogenoacetates Cu(CX3CO2)2, X = F, Cl or Br, and copper in the presence of carbon monoxide

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