Energetics of the rotational isomers of thiophenecarboxaldehydes in the ground state

Itoh, Takaò; Tanaka, Nobuaki; Nishikiori, Hiromasa; Fujii, Tsuneo

doi:10.1016/j.cplett.2011.08.043

Cited by 4 publications

(2 citation statements)

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“…In a previous study on carboxaldehydes, Itoh et al studied the energetics of the conformers of 2and 3-thiophenecarboxaldehydes in argon matrices by means of matrix-isolation infrared spectroscopy [36]. Their analysis using density functional theory and coupled-cluster calculations are in agreement with our results.…”

Section: Geometry Optimizationssupporting

confidence: 88%

The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

et al. 2020

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We report on the structures of two conformers of 2-thiophenecarboxaldehyde as obtained using a combination of molecular jet Fourier-transform microwave spectroscopy and quantum chemical calculations. The microwave spectrum was recorded using two spectrometers operating in the frequency ranges of 2.0 GHz to 26.5 GHz and 26.5 GHz to 40.0 GHz. The spectra of all singlysubstituted heavy atom isotopologues 13 C, 18 O, and 34 S in their natural abundances could be measured and assigned to determine the experimental gas-phase substitution rs and semi-empirical re SE structures of the most abundant conformer. The spectrum of the 33 S isotopologue with its nuclear quadrupole coupling hyperfine structure was analyzed, yielding the complete quadrupole tensor with aa = 22.63799(76),  = bb  cc = 18.4892( 14), and ab = 12.002(33) MHz.Quantum chemical calculations for the electric field gradient tensor including corrections with a calibration factor determined from 27 previous studies on the 33 S species predicted the 33 S nuclear quadrupole coupling constants of 2-thiophencarboxaldehyde with high quality. The experimental results are used to map the observed rotational constants to the corresponding molecular structure obtained from quantum chemical calculations, which predicted two conformers with an energy difference of about 6 kJmol 1 at the MP2/6-311++G(d,p) level of theory. Insight into the conformational stability of aromatic heterocyclic carboxaldehydes and bond situations of the sulfur atom extracted from the hyperfine structure of the 33 S nucleus are discussed within the frame of the current literature. This work provides an important contribution to the study and characterization of sulfur-containing volatile organic compounds.

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Section: Geometry Optimizationssupporting

confidence: 88%

The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

et al. 2020

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“…Itoh [45] showed coexistence of anti and syn rotamers for 2-thiophenecarboxaldehyde through matrix-isolation infrared spectroscopy combined with UV photoexcitation as well as DFT and Coupled Cluster calculations. It was revealed that the syn rotamer was more stable than the anti rotamer for 2-thiophenecarboxaldehydes.…”

Section: Quantum Chemical Calculationsmentioning

confidence: 99%

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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Molecular structure and non-covalent interaction of 2-thiophenecarboxaldehyde and its monohydrated complex

Jin

et al. 2019

The Journal of Chemical Physics

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The rotational spectrum of 2-thiophenecarboxaldehyde was investigated by using supersonic jet Fourier transform microwave spectroscopy. The measurements were extended to the 34S, 33S, 13C, and 18O isotopologs for the cis conformer, as well as to the 34S and 13C isotopologs for the trans conformer, leading to an accurately structural determination of the two observed conformers. The unchanged experimental Pcc values upon isotopic substitution indicate effective planar geometries of the two conformers. The ring structures of thiophene are slightly different between the cis and trans conformers. Two isomers of the monohydrated complex of 2-thiophenecarboxaldehyde, formed between a cis or trans monomer with water stabilized by an O—H⋯O hydrogen bond (HB) and an additional (C=O)CH⋯O(H2O) or (Cring)CH⋯O(H2O) HB, respectively, were observed in jet expansion. The noncovalent interactions attributed to the stabilization of the monomer and the monohydrated complex are revealed by quantum chemical methods. The interaction energy for trans-w-1 is 4 kJ mol−1 larger than that of cis-w-1, attributed to the relative stronger CH⋯O HB. The relative abundance of the two conformers of the 2-thiophenecarboxaldehyde monomer and the two isomers of the complex was estimated in the jet.

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Energetics of the rotational isomers of thiophenecarboxaldehydes in the ground state

Cited by 4 publications

References 9 publications

The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

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

Molecular structure and non-covalent interaction of 2-thiophenecarboxaldehyde and its monohydrated complex

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Energetics of the rotational isomers of thiophenecarboxaldehydes in the ground state

Cited by 4 publications

References 9 publications

The heavy atom structures and 33S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

The heavy atom structures and 33S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

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

Molecular structure and non-covalent interaction of 2-thiophenecarboxaldehyde and its monohydrated complex

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The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy

The heavy atom structures and ³³S quadrupole coupling constants of 2-thiophenecarboxaldehyde: insights from microwave spectroscopy