Vibrational optical activity in para-substituted 1-methylcyclohex-1-enes

Polavarapu, Prasad L.; DIEM, M.; Nafie, Laurence A.

doi:10.1021/ja00537a003

Cited by 18 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it was not possible to accurately determine how many bands contribute to the observed chiral spectrum, because a complicated spectral overlap between positive- and negative-signed chiral peaks, which in part cancel out one another, makes it challenging to fit the data unambiguously. Other FT-IR, Raman, and VCD studies have reported that three or more vibrational modes could contribute to the corresponding C–H stretch vibrational spectra of chiral limonene liquid. ,− A more reliable and accurate determination method for the spectroscopic parameters has thus been needed. We here perform global fitting analyses of multiple sets of time-delayed VSFG spectra to determine the spectroscopic parameters of R -(+)-limonene.…”

supporting

confidence: 88%

Time-Variable Chiroptical Vibrational Sum-Frequency Generation Spectroscopy of Chiral Chemical Solution

Lee

Nah

et al. 2021

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

Vibrational sum-frequency generation (VSFG) spectroscopy, a surface-specific technique, was shown to be useful even for characterizing the vibrational optical activity of chiral molecules in isotropic bulk liquids. However, accurately determining the spectroscopic parameters is still challenging because of the spectral congestion of chiroptical VSFG peaks with different amplitudes and phases. Here, we show that a time-variable infrared–visible chiroptical three-wave-mixing technique can be used to determine the spectroscopic parameters of second-order vibrational response signals from chiral chemical liquids. For varying the delay time between infrared and temporally asymmetric visible laser pulses, we measure the chiral VSFG, achiral VSFG, and their interference spectra of bulk R-(+)-limonene liquid and perform a global fitting analysis for those time-variable spectra to determine their spectroscopic parameters accurately. We anticipate that this time-variable VSFG approach will be useful for developing nearly background-free chiroptical characterization techniques with enhanced spectral resolution.

show abstract

supporting

confidence: 88%

Time-Variable Chiroptical Vibrational Sum-Frequency Generation Spectroscopy of Chiral Chemical Solution

Lee

Nah

et al. 2021

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

show abstract

“…The mostly applied mid-IR spectral range used for VCD ranges from 1800 cm À1 to 1000 cm À1 since skeleton vibrations near to the stereocenters are typically in this area. Polavarapu et al [41] and Abbate et al [65] studied the CH stretching region which is not often used in VCD analysis. Likewise, Singh and Keiderling [66] studied limonene using VCD in the CH stretching region and in the region of the important skeleton vibrations.…”

Section: Vcdmentioning

confidence: 99%

Stereochemical analysis of (+)-limonene using theoretical and experimental NMR and chiroptical data

Reinscheid

2016

Journal of Molecular Structure

View full text Add to dashboard Cite

a b s t r a c tUsing limonene as test molecule, the success and the limitations of three chiroptical methods (optical rotatory dispersion (ORD), electronic and vibrational circular dichroism, ECD and VCD) could be demonstrated. At quite low levels of theory (mpw1pw91/cc-pvdz, IEFPCM (integral equation formalism polarizable continuum model)) the experimental ORD values differ by less than 10 units from the calculated values. The modelling in the condensed phase still represents a challenge so that experimental NMR data were used to test for aggregation and solventesolute interactions. After establishing a reasonable structural model, only the ECD spectra prediction showed a decisive dependence on the basis set: only augmented (in the case of Dunning's basis sets) or diffuse (in the case of Pople's basis sets) basis sets predicted the position and shape of the ECD bands correctly. Based on these result we propose a procedure to assign the absolute configuration (AC) of an unknown compound using the comparison between experimental and calculated chiroptical data.

show abstract

“…31,32 In this work, we report using high-resolution SFG spectroscopy to capture the details of achiral, chiral, and prochiral spectral signatures of the S-(-)-limonene and R-(+)-limonene molecules at their air/liquid interfaces. Our interest in the limonene molecules is not only because it has been a benchmark choice for studying molecular chirality with various chiroptical and spectroscopic techniques in the bulk, 10,15,[33][34][35][36] but also because of the importance of a class of chiral isoprene and monoterpene molecules, such as limonene and pinene, etc., in the global secondary organic aerosol (SOA) formation and impact on climate changes. [37][38][39][40][41][42] It has been shown that chirality is not only an important component in the SOA, 39,40 the surface structure and reactivity of these SOA particles are also crucial for understanding the transformation and impact of the SOAs.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic Chirality and Prochirality at Air/R‐(+)‐ and S‐(–)‐Limonene Interfaces: Spectral Signatures With Interference Chiral Sum‐Frequency Generation Vibrational Spectroscopy

Zhang

Wei

et al. 2014

Chirality

View full text Add to dashboard Cite

We report in this work detailed measurements of the chiral and achiral sum-frequency vibrational spectra in the C-H stretching vibration region (2800-3050 cm(-1)) of the air/liquid interfaces of R-(+)-limonene and S-(-)-limonene, using the recently developed high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The achiral SFG spectra of R-limonene and S-limonene, as well as the RS racemic mixture (50/50 equal amount mixture), show that the corresponding molecular groups of the R and S enantiomers are with the same interfacial orientations. The interference chiral SFG spectra of the limonene enantiomers exhibit a spectral signature from the chiral response of the Cα-H stretching mode, and a spectral signature from the prochiral response of the CH(2) asymmetric stretching mode, respectively. The chiral spectral feature of the Cα-H stretching mode changes sign from R-(+)-limonene to S-(-)-limonene surfaces, and disappears for the RS racemic mixture surface. While the prochiral spectral feature of the CH(2) asymmetric stretching mode is the same for R-(+)-limonene and S-(-)-limonene surfaces, and also surprisingly remains the same for the RS racemic mixture surface. Therefore, the structures of the R-(+)-limonene and the S-(-)-limonene at the liquid interfaces are nevertheless not mirror images to each other, even though the corresponding groups have the same tilt angle from the interfacial normal, i.e., the R-(+)-limonene and the S-(-)-limonene at the surface are diastereomeric instead of enantiomeric. These results provide detailed information in understanding the structure and chirality of molecular interfaces and demonstrate the sensitivity and potential of SFG-VS as a unique spectroscopic tool for chirality characterization and chiral recognition at the molecular interface.

show abstract

Vibrational optical activity in para-substituted 1-methylcyclohex-1-enes

Cited by 18 publications

References 0 publications

Time-Variable Chiroptical Vibrational Sum-Frequency Generation Spectroscopy of Chiral Chemical Solution

Time-Variable Chiroptical Vibrational Sum-Frequency Generation Spectroscopy of Chiral Chemical Solution

Stereochemical analysis of (+)-limonene using theoretical and experimental NMR and chiroptical data

Intrinsic Chirality and Prochirality at Air/R‐(+)‐ and S‐(–)‐Limonene Interfaces: Spectral Signatures With Interference Chiral Sum‐Frequency Generation Vibrational Spectroscopy

Contact Info

Product

Resources

About