CONFORMATIONAL EQUILIBRIA IN OPEN-CHAIN α,β-UNSATURATED KETONES

1961 ◽  
Vol 39 (11) ◽  
pp. 2225-2235 ◽  
Author(s):  
K. Noack ◽  
R. Norman Jones
Keyword(s):  
Raman Spectra ◽  
Equilibrium Mixture ◽  
Infrared And Raman Spectra ◽  
Temperature Dependent ◽  
Trans Form ◽  
Open Chain ◽  
Unsaturated Ketones ◽  
Conformational Isomers ◽  
Alkyl Substitution ◽  
Conformational Equilibria

The infrared and Raman spectra of trans-Δ3-penten-2-one have been measured over the temperature range +30° to −75° and +85° to +5° respectively. The temperature-dependent changes observed in the spectra indicate that this ketone exists as an equilibrium mixture of s-cis and s-trans conformational isomers in the liquid state. The s-trans form is the more stable and is present exclusively in the crystalline solid.Similar measurements have been carried out on Δ3-buten-2-one. The infrared and Raman spectra of this ketone also exhibit temperature effects that can be explained by a similar equilibrium, though the evidence is not as conclusive as for trans-Δ3-penten-2-one.The influence of alkyl substitution at the α- and β-carbon atoms on the relative stability of the s-cis and s-trans forms of α,β-unsaturated ketones is discussed.

Infrared and Raman spectra, ab initio calculations and conformational equilibria of chloromethyl methyl dichlorosilane

2001 ◽  
Vol 597 (1-3) ◽  
pp. 137-155 ◽  
Author(s):  
P Klaeboe ◽  
C.J Richard ◽  
C.J Nielsen ◽  
D.L Powell ◽  
V Aleksa ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Infrared And Raman Spectra ◽  
Conformational Equilibria

Total Synthesis of the Antitumor Depsipeptide FE399 and its S-Benzyl Derivative: A Macrolactamization Approach

2020 ◽  
Author(s):  
Takayuki Tonoi ◽  
Miyuki Ikeda ◽  
Teruyuki Sato ◽  
Ryo Kawahara ◽  
Takatsugu Murata ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Total Synthesis ◽  
Natural Product ◽  
Condensation Reaction ◽  
Practical Method ◽  
Equilibrium Mixture ◽  
Conformational Isomers ◽  
Single Isomer

<div>An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.</div>

Vibration spectra of sulphur tetranitride

1981 ◽  
Vol 46 (11) ◽  
pp. 2613-2619 ◽  
Author(s):  
Jiří Toužín
Keyword(s):  
Solid State ◽  
Raman Spectra ◽  
Normal Coordinate Analysis ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Vibration Spectra

Available data on infrared and Raman spectra of S4N4 in solid state and solutions have been verified and completed. On the basis of normal coordinate analysis an attempt has been made to define with more precision the interpretation of vibration spectra of this compound given in earlier reports.

Vibrational spectra of aquadioxotetra; peroxodivanadates(V) M2[V2O2(O2)4(H2O)]·xH2O (M = N(CH3)4, Cs)

1990 ◽  
Vol 55 (6) ◽  
pp. 1485-1490 ◽  
Author(s):  
Peter Schwendt ◽  
Milan Sýkora
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Infrared And Raman Spectra ◽  
Empirical Correlations ◽  
Normal Coordinate ◽  
Bond Lengths ◽  
Stretching Vibrations

The infrared and Raman spectra of M2[V2O2(O2)4(H2O)]·xH2O and M2[V2O2(O2)4(D2O)]·xD2O (M = N(CH3)4, Cs) were measured. In the region of the vanadium-oxygen stretching vibrations, the spectra were interpreted based on normal coordinate analysis, employing empirical correlations between the bond lengths and force constants.

Infrared and Raman Spectra, conformations,ab initio calculations and spectral assignments of 1,3-disilabutane (SiH3CH2SiH2CH3)

2007 ◽  
Vol 38 (9) ◽  
pp. 1159-1173 ◽  
Author(s):  
Gamil A. Guirgis ◽  
Paul M. Mazzone ◽  
Daniel N. Pasko ◽  
Peter Klaeboe ◽  
Anne Horn ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Infrared And Raman Spectra

The split-up of G band and 2D band in temperature-dependent Raman spectra of suspended graphene

2021 ◽  
Vol 139 ◽  
pp. 106960 ◽  
Author(s):  
Yi Liu ◽  
Yafang Shi ◽  
Wenguang Zhou ◽  
Wei Shi ◽  
Wei Dang ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Temperature Dependent ◽  
Suspended Graphene

Infrared and Raman spectra, vibrational assignment, and ab initio calculations of fluoromalononitrile

1997 ◽  
Vol 53 (12) ◽  
pp. 2001-2012 ◽  
Author(s):  
M. Dakkouri ◽  
A. Grunvogel-Hurst ◽  
Gamil A. Guirgis ◽  
Zhenhong Yu ◽  
Yanping Jin ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Infrared And Raman Spectra ◽  
Vibrational Assignment
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