Conformational studies of monosubstituted three-membered rings by variable temperature FT-IR spectra of rare gas solutions

Durig, J. R.; Yu, Zhenhong; Shen, Shiyu; Warren, Robin D.; Verma, Vishwa Nath; Guirgis, Gamil A.

doi:10.1016/s0022-2860(00)00875-9

Cited by 10 publications

(9 citation statements)

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“…The result was E ap – E sc = 1.7 kJ/mol with an estimated one standard deviation of 0.8 kJ/mol. This value is lower than 3.13(31) kJ/mol found for this compound dissolved in xenon, , demonstrating that even the apolar solvent xenon influences conformational composition. It is noted that the experimental value of 1.7(8) kJ/mol is lower than the CCSD electronic energy difference (2.94 kJ/mol; Table ), the B3LYP electronic energy difference (2.65 kJ/mol), and the MP2 result corrected for zero-point energies (2.54 kJ/mol; see above).…”

Section: Resultscontrasting

confidence: 59%

“…Conformational and structural studies of methylcyclopropane derivatives (C 3 H 5 CH 2 X) have received considerable attention in the past. Microwave (MW), infrared (IR), and Raman spectroscopic studies, often augmented by quantum chemical calculations, have been reported for a number of them including X = F, − Cl, ,− Br, ,,, I, , OH, SH, SeH, NH 2 , PH 2 , CH 3 , SiH 3 , − SiF 3 , ,, CN, , CCH, , and NC …”

Section: Introductionmentioning

confidence: 99%

“…We have therefore undertaken the first MW investigation of (fluoromethyl)cyclopropane. The MW study has been augmented with quantum chemical calculations at a much higher level than previously. ,, These computations were conducted with the purpose of obtaining information for use in assigning the MW spectrum and investigating properties of the potential-energy hypersurface.…”

Section: Introductionmentioning

confidence: 99%

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Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)

2014

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The microwave spectrum of (fluoromethyl)cyclopropane, C3H5CH2F, has been investigated in the whole 12-75.6 GHz spectral range. Many measurements were also performed in the 75.6-120 GHz region. The spectra of two conformers were assigned. The H-C-C-F chain of atoms is antiperiplanar in the conformer denoted ap and synclinal in the sc rotamer. The sc conformer has a lower energy than ap. The internal energy difference was determined to be E(ap) - E(sc) = 1.7(8) kJ/mol from relative intensity measurements. The spectra of the ground vibrational state and seven vibrationally excited states belonging to two different normal modes were assigned for sc. The frequencies of these two modes were determined by relative intensity measurements. The dipole moment of this conformer was determined to be μ(a) = 5.520(17), μ(b) = 3.475(29), μ(c) = 0.35(13), and μ(TOT) = 6.532(40) × 10(-30) C m [1.958(12) D]. The spectrum of the ground vibrational state was assigned for ap. The microwave work was supported by quantum chemical calculations at the CCSD/cc-pVQZ, MP2/cc-pVTZ, and B3LYP/cc-pVTZ levels of theory.

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Section: Resultscontrasting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)

2014

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“…This spectrum resembles that of Durig and Little, with the qualification that their spectrum was obtained in a reflection mode with the sample deposited on a “blackened brass plate” near 77 K . The same research group published band assignments and an extensive vibrational analysis in that paper and subsequent papers, − to which the reader is directed for details.…”

Section: Resultsmentioning

confidence: 99%

“…However, the agreement in terms of peak positions is excellent. Again, interested readers are referred to earlier papers for a full set of peak positions and assignments. − …”

Section: Discussionmentioning

confidence: 99%

Solid-State Isomerization and Infrared Band Strengths of Two Conformational Isomers of Cyclopropanecarboxaldehyde, a Candidate Interstellar Molecule

Hudson

Coleman

2019

ACS Earth Space Chem.

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At least a dozen of the known interstellar molecules possess a formyl group (HCO), suggesting that other such species exist and await discovery in the interstellar medium. Here we examine the mid-infrared (mid-IR) spectrum and selected physical properties of one such candidate, cyclopropanecarboxaldehyde, in amorphous ices. Mid-IR transmission spectra of solid cyclopropanecarboxaldehyde are presented for the first time and used to determine the cis-to-trans ratio of conformational isomers present in amorphous samples. The measured ratio is compared to one from an electron-diffraction study of the gas-phase compound. The cis-to-trans isomerization in the amorphous compound is followed and the activation energy is determined. The first IR band strengths for solid cyclopropanecarboxaldehyde are reported. Also presented are refractive indices and densities at 15 K for amorphous forms of two related compounds, cyclopropane and cyclopropanemethanol. Two low-temperature reactions for the interstellar formation of cyclopropanecarboxaldehyde are briefly described.

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Structure and conformational dynamics of the cyclopropanecarbaldehyde molecule in the ground (Sb0) and lowest excited (Tb1 and Sb1) electronic states

2009

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The structure and conformational dynamics of nonrigid cyclopropanecarbaldehyde (CPCA) molecule in the ground (S 0 ) and lowest excited triplet (Т 1 ) and singlet (S 1 ) electronic states were calculated using the MP2, DFT, CASSCF, CASPT2, and CCSD quantum chemical methods. According to ab initio calculations, in the S 0 electronic state there are two symmetri cal (cis and trans) conformers of the CPCA molecule. Excitation of the CPCA molecule to the Т 1 and S 1 electronic states causes significant structural changes: carbonyl ССНО fragment becomes nonplanar, cyclopropane fragment rotates around the C-C bond, thus changing the relative positions of the formyl and cyclopropane fragments. Using sections of the potential energy surfaces (PES) of the CPCA molecule in the Т 1 and S 1 states, we calculated the torsion and inversion wave functions and vibrational transition energies. The results obtained suggest a strong coupling of the torsion and inversion motions in the Т 1 and S 1 excited states.Experimental and theoretical research of the struc ture of molecules with cyclopropyl substituents is of considerable interest because of unique physical and chemical properties of such systems. 1,2 A number of ex perimentally established properties of substituted cyclo propanes can be interpreted within the framework of the Walsh-Hoffmann model, 1-4 which provides an explana tion for the ability of the cyclopropyl moiety to con jugation with unsaturated substituents. However, in some cases the cyclopropyl fragments are more similar to alkyl rather than unsaturated substituents as regards the effect on the structure and properties of molecules. 1,2To develop molecular models with high predictive power, one should obtain and collect detailed informa tion on the structure and properties of molecules and chemical substances. The present work is a continuation of our systematic theoretical and experimental studies 5-7 on the structure and conformational dynamics of mol

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Conformational studies of monosubstituted three-membered rings by variable temperature FT-IR spectra of rare gas solutions

Cited by 10 publications

References 10 publications

Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)

Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)

Solid-State Isomerization and Infrared Band Strengths of Two Conformational Isomers of Cyclopropanecarboxaldehyde, a Candidate Interstellar Molecule

Structure and conformational dynamics of the cyclopropanecarbaldehyde molecule in the ground (Sb0) and lowest excited (Tb1 and Sb1) electronic states

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Conformational studies of monosubstituted three-membered rings by variable temperature FT-IR spectra of rare gas solutions

Cited by 10 publications

References 10 publications

Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C3H5CH2F)

Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C3H5CH2F)

Solid-State Isomerization and Infrared Band Strengths of Two Conformational Isomers of Cyclopropanecarboxaldehyde, a Candidate Interstellar Molecule

Structure and conformational dynamics of the cyclopropanecarbaldehyde molecule in the ground (Sb0) and lowest excited (Tb1 and Sb1) electronic states

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Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)

Microwave Spectrum, Conformational Composition, and Dipole Moment of (Fluoromethyl)cyclopropane (C₃H₅CH₂F)