Conformational Analysis of 1-Chloro- and 1-Bromo-2-propanol

Gonçalves, Karla M. S.; Garcia, Danielle Rodrigues; Ramalho, Teodorico C.; Figueroa‐Villar, José Daniel; Freitas, Matheus P.

doi:10.1021/jp408528j

Cited by 9 publications

(15 citation statements)

References 24 publications

(37 reference statements)

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“…Because no vibrational modes for 1-chloro-2-propanol molecule are available in the literature, we have performed DFT calculation for the fundamental frequencies and the corresponding modes of the g,g′-conformer of this molecule which are also included in Table for comparison. The g,g′ conformer is the most stable geometry of isolated ClCH 2 CH(CH 3 )OH, as shown in Scheme S1 . However, the presence of other less-stable conformers of ClCH 2 CH(CH 3 )OH on Cu(100) at low temperatures cannot be completely ruled out.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The g,g′ conformer is the most stable geometry of isolated ClCH 2 CH(CH 3 )OH, as shown in Scheme S1. 25 However, the presence of other less-stable conformers of ClCH 2 CH(CH 3 )OH on Cu(100) at low temperatures cannot be completely ruled out. According to the surface dipole selection rule of RAIRS which states that only the vibrational modes with nonzero dynamic dipole moments perpendicular to the surface are active, 26 several adsorption characteristics for the chloropropanol molecules in the multilayers can be excluded.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)

Yang

Chen

et al. 2016

J. Phys. Chem. C

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Thermal reactions of bifunctional 1-chloro-2-propanol and 3-chloro-1-propanol on Cu(100) and oxygen-precovered Cu(100) are presented in this article. X-ray photoelectron spectroscopy, reflection–absorption infrared spectroscopy and temperature-programmed reaction/desorption have been employed to investigate the decomposition process of 1-chloro-2-propanol on Cu(100). The competitive dissociation of the functional C–Cl and CO–H at 265 K results in the formation of ClCH2CH(CH3)O– and −CH2CH(CH3)O– surface intermediates at a 2:1 concentration ratio. This ratio decreases to ∼0.6:1 at 300 K. The −CH2CH(CH3)O– oxametallacycle is theoretically predicted to be bonded on the Cu(100) surface, with both the O and CH2 at bridge sites. This surface intermediate decomposes mainly at 300 K producing CH3C(O)CH3 and CH3CHCH2 in addition to H2 and CO. Preadsorbed oxygen atoms can stabilize the oxametallacycle and increases its reaction temperature to ∼350 K. Moreover, propene formation is promoted relative to acetone. In the reaction of 3-chloro-1-propanol on Cu(100), a low-temperature (159 K) formation channel of ClCH2CHCH2 is observed. Other products presumably from −CH2CH2CH2O– reaction, including CH2CHCHO, CH3CH2CHO, C2H4, CO, and H2, evolve at a temperature higher than ∼300 K. No propene from C–O dissociation is formed. Preadsorption of oxygen causes the evolution of these products to be shifted to ∼400 K, with additional CH3CH2CH2OH and a small amount of CH3CHCH2. The theoretical calculation indicates that −CH2CH2CH2O– is bonded via the 3CH2 and O at atop and bridge sites, respectively, and has an energy slightly higher than that of −CH2CH(CH3)O–, by 3.4 kcal·mol–1.

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Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)

Yang

Chen

et al. 2016

J. Phys. Chem. C

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“…Unlike 3,5-dimethylcyclohexoxy, the 3,4-dimethylcyclohexoxy radical had C 1 symmetry. The vicinal methyl substituent increased the energy of 1.53 kcal/mol above 3,5-dimethylcyclohexoxy because of the additional gauche-butane type steric interaction ,− introduced by the two methyl groups substituted on adjacent carbons of the ring (Scheme ), and thus, the X̃ state of 3,4-dimethylcyclohexoxy was destabilized. Overlapping the origin bands of the two spectra via adjusting the horizontal axis revealed that the 3,4-dimethylcyclohexoxy spectrum (Figure a) contained all strong bands in the 3-methylcyclohexoxy spectrum (Figure b).…”

Section: Results and Discussionmentioning

confidence: 99%

Methyl Substitution Effect on the Jet-Cooled Laser-Induced Fluorescence Spectrum of Cyclohexoxy Radical

Wang

2015

J. Phys. Chem. A

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Understanding the structure and properties of cyclohexoxy radical and its substitutes is important because of their presence in combustion processes, in atmospheric chemistry, and as intermediates in the hydrocarbon reactions. In this work, jet-cooled laser-induced fluorescence (LIF) spectra of five dimethyl substituted cyclohexoxy radicals are obtained for the first time. The correlation between the spectral variations and the radical structural changes is studied with the assistance of theoretical calculations at the B3LYP/6-31+G(d) and CASSCF/6-31+G(d) levels. The results show that the spectral characters of the dimethylcyclohexoxy radicals and their dissociation kinetics are predominantly affected by the methyl substitution position related to the C-O group. The spectral effect of the two methyl groups will add up if they locate on asymmetric carbons of the cyclohexoxy ring. Methyl substitution on β carbon weakens the six-member ring of cyclohexoxy and results in unimolecular dissociation via β C-C bond cleavage on the methyl group side and forms vinoxy variants. This study clearly shows that the LIF spectra can be used to identify cyclohexoxy and the isomers of its methyl substitutes. The results will help to understand the photochemistry of cyclic hydrocarbons in the atmospheric and combustion processes.

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“…Immediately, after computational methods convincingly gained in accuracy and modeling capability, they became the preferential analytical tools to study conformer distribution statistics (Boltzmann distribution) and ultimately the calculation of the weighted average of chemical shifts and coupling constants for flexible molecules. [7][8][9][10][11][12][13][14] The concept of diastereotopicity is crucial in the realm of enzyme biochemistry as highlighted by reactions that specifically involve the recognition of diastereotopic ligands, in these cases protons. For example, fumarase hydratase (EC 4.2.1.2) promotes the water elimination from sodium malate by removing the (pro)-R proton 14 while during the Krebs cycle, a pro-R hydrogen from citric acid is abstracted and eliminated by aconitase (EC 4.2.1.3).…”

Section: Introduction *mentioning

confidence: 99%

1H NMR and conformational analysis of diastereotopic methylene protons in achiral flexible molecules

Gheorghiu¹,

Valdez²,

Racoveanu³

2021

Rev.Roum.Chim.

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Unlike diastereotopic -CH2- protons from chiral compounds, the diastereotopic protons from achiral compounds may not be easily predictable. For molecules with flexible chain this task is even more problematic. Additionally, the assignment from the experimental 1H NMR spectrum of chemical shifts and coupling constants is very frequently uncertain. Nevertheless, computationally, for both chiral and achiral molecules the -CH2- protons diastereotopic nature is evident as well as NMR parameters assignments. In the present paper we examine the NMR parameters calculated as a sum of Boltzmann weighted average of the lowest conformations that fits a window less than 10 kJ/mole. A Spartan20 six steps protocol was chosen to select the lower energy conformations. The NMR conformationally averaged parameters obtained for 2-ethyl-2-hyroxybutanoic acid (EHB) and citric acid (CA), both achiral molecules, and the chiral malic acid (MA) fit acceptable well with the experimental data, although the calculation is done for gas phase (conformations dominated by intermolecular hydrogen bonding) and the experiment was carried out in D2O (conformations controlled by intermolecular hydrogen bonding of highly decorated molecules with OH and COOH that can interact with the solvent). In addition, in the present paper we have examined EHB, CA and MA the lowest energy conformer geometry, Atom in Molecules (AIM) and Natural Bond Orbital protocols to identify the intramolecular hydrogen bonds.

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Conformational Analysis of 1-Chloro- and 1-Bromo-2-propanol

Cited by 9 publications

References 24 publications

Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)

Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)

Methyl Substitution Effect on the Jet-Cooled Laser-Induced Fluorescence Spectrum of Cyclohexoxy Radical

1H NMR and conformational analysis of diastereotopic methylene protons in achiral flexible molecules

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Conformational Analysis of 1-Chloro- and 1-Bromo-2-propanol

Cited by 9 publications

References 24 publications

Comparison of the Chemistry of ClCH2CH(CH3)OH and ClCH2CH2CH2OH on Cu(100) and O/Cu(100)

Comparison of the Chemistry of ClCH2CH(CH3)OH and ClCH2CH2CH2OH on Cu(100) and O/Cu(100)

Methyl Substitution Effect on the Jet-Cooled Laser-Induced Fluorescence Spectrum of Cyclohexoxy Radical

1H NMR and conformational analysis of diastereotopic methylene protons in achiral flexible molecules

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Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)

Comparison of the Chemistry of ClCH₂CH(CH₃)OH and ClCH₂CH₂CH₂OH on Cu(100) and O/Cu(100)