Interaction of Anions with Perfluoro Aromatic Compounds

Alkorta, Ibón; Rozas, Isabel; Elguero, José

doi:10.1021/ja025693t

Cited by 506 publications

(419 citation statements)

References 32 publications

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“…The parameters of the ring critical point RCP (Figure 4) may also be considered as descriptors of hydrogen bond strength [99]. Correlations between the characteristics of RCPs and other parameters describing H-bond strength were observed by Alkorta [100,101]. There is also a good correlation between electron density at BCP H…Y and H-bond energy for pyrrole-2-carboxylic acid dimers [40].…”

Section: Aim Studiesmentioning

confidence: 96%

Conformational Preferences of 2-Acylpyrroles in Light of FT-IR and DFT Studies

Dubis

2014

J Phys Chem Biophys

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2-carboxylic acids [3] and corresponding esters [4]. Pyrrole-2-carboxylates are also useful substrates for the preparation of more complex pyrrole containing systems [5] such as ketorolac, a drug with anti-inflammatory and analgesic properties [6]. It is noted that the 2-acylpyrrole motif is widespread in nature. There are many examples of 2-acylpyrrole based molecules (Figure 1) with various biological activities [7,8]. Representative examples are pyoluteorin and pyrrolomycin D, secondary metabolites produced by marine Conformational Preferences of 2-Acylpyrroles in Light of FT-IR and DFT StudiesAlina T Dubis* Institute of Chemistry, University of Białystok, Hurtowa 1, Poland AbstractConformations of alpha-substituted pyrroles have been effectively studied using spectroscopic methods assisted by theoretical calculations developed in the recent decade. The question of how to effectively study the conformation of 2-acylpyrrole no longer remains unanswered. The detailed spectroscopic studies conducted in the last decade and interpreted on the basis of theoretical calculations provide a satisfactory answer to that question. Based on the Density Functional Theory (DFT) calculations of conformational properties of 2-acylpyrroles, for which two stable rotameric forms were predicted, syn and anti-conformers have been studied either by experimental or theoretical methods. The family of 2-acylpyrroles have both a proton donor N-H group and a proton acceptor C=O group. This structure favors the formation of doubly hydrogen-bonded cyclic dimers connected by two N-H...O=C bonds. The tendency to form cyclic dimers stabilizes the syn-conformation. Due to these properties 2-acylpyrroles can be used as structural models for the conformational analysis of peptides.This review summarizes recent investigations of conformations of 2-acylpyrroles, with a particular emphasis on the hydrogen bonds forming within these systems. The influence of 2-substitution on different aspects of stability of these molecular systems and the usefulness of infrared spectroscopy supported by theoretical calculations in H-bonds and conformational studies are discussed. Among the molecular properties hydrogen bond energy, structural characteristics such as C=O bond length of dimers and unique spectral features of 2-acylpyrroles that can be used to predict and investigate the conformation and structure of proteins are considered.Graphical abstract. The potential energy diagram of 2-acylpyrroles as a function of the dihedral angle pyrrole ringcarbonyl group of bond rotation. Most stable conformer syn converts to conformer anti via the transition state TS1; less stable conformer anti converts to conformer syn via the transition state TS2. conformational research and can greatly support experimental work with quite good accuracy. Among the most useful parameters are geometrical parameters, relative conformational energies, barriers to internal rotation and vibrational frequencies for each conformer. Journal of Physical Chemistry & BiophysicsEnergy differ...

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Section: Aim Studiesmentioning

confidence: 96%

Conformational Preferences of 2-Acylpyrroles in Light of FT-IR and DFT Studies

Dubis

2014

J Phys Chem Biophys

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“…Pertinent anion transport experiments have identified anion-p interactions 1,4 and halogen bonds 5,6 as promising candidates to contribute to the acceleration of transformations with anionic transition states. Anion-p interactions [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] are particularly intriguing because the complementary cation-p interactions are essential in biocatalysis 25,26 and are increasingly used in organocatalysis 25,27,28 . In sharp contrast, anion-p interactions are essentially unexplored in catalysis 23,24 .…”

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confidence: 99%

“…To attract anions, the negative quadrupole moment of p-basic aromatics has to be inverted. This is possible with the introduction of strongly electron-withdrawing substituents 1,4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] . Popular examples are hexafluorobenzene or 2,4,6-trinitrotoluene.…”

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confidence: 99%

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Enolate chemistry with anion–π interactions

2014

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“…Theoretical calculations showed that attractive electrostatic interactions exist between perfluoro aromatic compounds, such as hexafluorobenzene, and several anions [10]. These results prompted us to investigate whether this type of interaction is present in 1 and 2 and to which extent this can influence the geometry of PCP-pincer Ru(II) complexes.…”

Section: Introductionmentioning

confidence: 99%

(P-Bis(pentafluorophenyl) substituted) PCP-pincer Ru(II) complexes: A theoretical study of the molecular structure and electronic properties

Gagliardo

Havenith²,

Klink

et al. 2006

Journal of Organometallic Chemistry

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The differences between the molecular structures of the PCP-pincer complex [RuCl{C 6 + (2cat). The molecular interactions between the chloride ligand and the axial rings, as found in 1 and 2, respectively, have been studied computationally in the model systems [(C 6 X 5 PH 2 ) 2 Cl À ] (X = H, F). The calculations on 2cat show that in 2 it is most likely the attractive electrostatic interaction between the chloride ligand and the fluorinated phenyl rings that forces the C ipso atom to occupy an axial position rather than an equatorial one in the observed (X-ray of 2) square pyramidal arrangement. In 1, however, repulsive steric hindrance forces the PPh 3 ligand to take the apical position. The applicability of the TD-DFT method for the calculation of the electronic spectra of the PCP-pincer compounds 1 and 2 has been tested. The results indicate that the excitation energies calculated for both complexes are in a reasonable agreement with the experimental absorption maxima. However, for 1, all the calculated transition energies are underestimated.

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Interaction of Anions with Perfluoro Aromatic Compounds

Cited by 506 publications

References 32 publications

Conformational Preferences of 2-Acylpyrroles in Light of FT-IR and DFT Studies

Conformational Preferences of 2-Acylpyrroles in Light of FT-IR and DFT Studies

Enolate chemistry with anion–π interactions

(P-Bis(pentafluorophenyl) substituted) PCP-pincer Ru(II) complexes: A theoretical study of the molecular structure and electronic properties

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