Molecular Geometries and Vibrational Spectra of Phenol, Benzaldehyde, and Salicylaldehyde:  Experimental versus Quantum Chemical Data

Lampert, Heike; Mikenda, W.; Karpfen, Alfred

doi:10.1021/jp962933g

Cited by 169 publications

(85 citation statements)

References 43 publications

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“…These results are in line with the earlier reports on failures of electronic structure methods for the correct description of low-lying out-of-plane vibrational frequencies of benzene, 2,3 several planar arenes, [4][5][6][7][8] and other nonrigid molecules. 9 Similar pitfalls have been recently found by Shabahzian 10 for the challenging ͑B 6 C͒ 2− anion, particularly at the MP2 level of theory.…”

Section: Introductionsupporting

confidence: 92%

Intramolecular basis set superposition error effects on the planarity of benzene and other aromatic molecules: A solution to the problem

Asturiol

Duran

Salvador

2008

The Journal of Chemical Physics

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Recently, the surprising result that ab initio calculations on benzene and other planar arenes at correlated MP2, MP3, configuration interaction with singles and doubles ͑CISD͒, and coupled cluster with singles and doubles levels of theory using standard Pople's basis sets yield nonplanar minima has been reported. The planar optimized structures turn out to be transition states presenting one or more large imaginary frequencies, whereas single-determinant-based methods lead to the expected planar minima and no imaginary frequencies. It has been suggested that such anomalous behavior can be originated by two-electron basis set incompleteness error. In this work, we show that the reported pitfalls can be interpreted in terms of intramolecular basis set superposition error ͑BSSE͒ effects, mostly between the C-H moieties constituting the arenes. We have carried out counterpoise-corrected optimizations and frequency calculations at the Hartree-Fock, B3LYP, MP2, and CISD levels of theory with several basis sets for a number of arenes. In all cases, correcting for intramolecular BSSE fixes the anomalous behavior of the correlated methods, whereas no significant differences are observed in the single-determinant case. Consequently, all systems studied are planar at all levels of theory. The effect of different intramolecular fragment definitions and the particular case of charged species, namely, cyclopentadienyl and indenyl anions, respectively, are also discussed.

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Section: Introductionsupporting

confidence: 92%

Intramolecular basis set superposition error effects on the planarity of benzene and other aromatic molecules: A solution to the problem

Asturiol

Duran

Salvador

2008

The Journal of Chemical Physics

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“…Furthermore, the calculated IR spectrum of phenol H3 exhibits a very intense vibration at 1161 cm −1 without matching an experimental band. This vibration has also been obtained by other DFT calculations [93,95,96,98,113]. Despite of some C-C stretch character, this vibration has C-H and O-H in-plane bending character and has been assigned to a strong band at 1177 cm −1 in the IR spectrum of phenol vapor [114,115].…”

Section: Ir Spectra: Comparison Of Calculated To Experimental Resultssupporting

confidence: 69%

Electronic and Molecular Structures of Heteroradialenes: A Combined Synthetic, Computational, Spectroscopic, and Structural Study Identifying IR Spectroscopy as a Simple but Powerful Experimental Probe

Richthofen

Feldscher

Lippert

et al. 2013

Zeitschrift Für Naturforschung B

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The vicinity of a hydrogen bond donor (O-H) and a hydrogen bond acceptor (C=O or C=N-R) in salicylaldehydes and ortho-Schiff bases results in significant structural variations compared to the monosubstituted derivatives that are reflected in the electronic structure and thus in the spectroscopic properties. This interplay between intramolecular hydrogen bonding and multicenter π-electron delocalization is the origin of the concept of resonance-assisted hydrogen bonding (RAHB). Herein, the complexity is extended from one hydrogen bond donor-acceptor pair in salicylaldehyde and ortho-Schiff bases to three hydrogen bond donor-acceptor pairs in 2,4,6-tricarbonyl-and 2,4,6-triimine-substituted phloroglucinols (1,3,5-trihydroxybenzene), respectively. To evaluate the changes in the molecular and electronic structures, we have performed a comprehensive computational, spectroscopic, and structural study starting from monosubstituted benzene derivatives as references over ortho-disubstituted derivates to the sixfold-substituted derivatives. Whereas in salicylaldehydes, ortho-Schiff bases, and 2,4,6-tricarbonyl-phloroglucinols the phenolic O-protonated tautomers represent the energy minima, the N-protonated tautomers represent the energy minima in 2,4,6-triiminephloroglucinols. The analysis provides a keto-enamine resonance structure with six exocyclic double bonds to be dominant for these species reminiscent of [6]radialenes, which were termed heteroradialenes. These heteroradialenes are non-aromatic alicycles. However, the predominance of this resonance structure does not represent a sudden change going from the 2,4,6-tricarbonyl-to the 2,4,6-triimine-phloroglucinols, but a gradual increase of analogous resonance structure contributions is observed even in salicylaldehyde and ortho-Schiff bases demonstrating some hetero-orthoquinodimethane character. These changes are, besides in the molecular structures, well reflected in the IR spectra, which can therefore be used as a simple tool to probe the electronic structures in these systems. Interruption of the delocalized π system supporting the intramolecular hydrogen bond, i. e. going from 2,4,6-triimine-to 2,4,6-triamine-substituted phloroglucinols, reestablishes an O-protonated aromatic phloroglucinol system.

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“…The integrated IR intensities of both molecules are reported. It should be noted that these data are lacking in the literature, since Lampert et al 2 reported only the absorbances at band maxima for Ph-OH. Most recently, 13 the anharmonicities for the CH, OH, and OD stretching vibrations were determined from the overtones observed in the near-IR spectra of Ph-OH and Ph-OD.…”

Section: Introductionmentioning

confidence: 99%

“Troublesome” Vibrations of Aromatic Molecules in Second-Order Möller−Plesset and Density Functional Theory Calculations: Infrared Spectra of Phenol and Phenol-OD Revisited

et al. 2001

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The infrared spectra of phenol and phenol-OD are thoroughly reinvestigated, to resolve the contradictory assignment of some vibrations. The harmonic frequencies, integrated IR intensities, and potential energy distribution (PED) have been calculated by the B3LYP method with the 6-311++G(df,pd) basis set. The Fourier transform infrared (FT-IR) spectra of phenol and phenol-OD have been measured in carbon tetrachloride and cyclohexane solutions, in the frequency range 3700-400 cm -1 , and the experimental integrated infrared intensities are reported. On the basis of the results obtained, the detailed assignment of all the fundamental modes of Ph-OH and Ph-OD are presented. The study demonstrates that density functional B3LYP is clearly superior to the ab initio Hartree-Fock (HF) and second-order Möller-Plesset (MP2) methods in reliable prediction of the vibrational spectra of phenol. In particular, it is shown that scaling of the B3LYP-calculated frequencies of the CH and OH(OD) stretching vibrations by the scaling factor, derived by Baker et al. [J. Phys. Chem. A 1998, 102, 1412 gives excellent agreement between theoretical and experimental frequencies of these vibrations. Detailed theoretical investigations are performed for these troublesome normal modes in phenol and benzene, which show the largest deviations between the MP2-predicted frequencies and the experimental ones. It has been demonstrated that these modes have almost identical atomic displacements and potential energy distributions in both the molecules. The electron correlation effects and basis set dependences are examined, and the nature of these problematical vibrations in aromatic molecules is discussed.

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Molecular Geometries and Vibrational Spectra of Phenol, Benzaldehyde, and Salicylaldehyde: Experimental versus Quantum Chemical Data

Cited by 169 publications

References 43 publications

Intramolecular basis set superposition error effects on the planarity of benzene and other aromatic molecules: A solution to the problem

Intramolecular basis set superposition error effects on the planarity of benzene and other aromatic molecules: A solution to the problem

Electronic and Molecular Structures of Heteroradialenes: A Combined Synthetic, Computational, Spectroscopic, and Structural Study Identifying IR Spectroscopy as a Simple but Powerful Experimental Probe

“Troublesome” Vibrations of Aromatic Molecules in Second-Order Möller−Plesset and Density Functional Theory Calculations: Infrared Spectra of Phenol and Phenol-OD Revisited

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