Theory and application of photoelectron spectroscopy. 61. Detection of rotational isomers by variable temperature photoelectron spectroscopy. A new technique in the realm of molecular conformational analysis

Mueller, Claus; Schaefer, Werner; Schweig, Armin; Thon, N.; Vermeer, Hans J.

doi:10.1021/ja00434a005

Cited by 54 publications

(11 citation statements)

References 3 publications

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“…The situation in vinyl mercaptan (or vinyl alcohol) is probably best rationalized in terms of orbital interactions as well as steric effects. Interaction (6) between HOMO of a double (6) bond and the appropriate pz orbital occupied by two lone-pair electrons involves four electrons and hence is destabilizing. 35 This unfavorable interaction should lead to a bond-angle widening of C2C1S1.…”

Section: Discussionmentioning

confidence: 99%

“…6 In fact, the 44-31G calculations do predict that the syn and a gauche (Figure 2) are two stable conformations with the syn being lower in energy by 0.7 kcal mol-'. The most stable structure for methyl vinyl sulfide has experimentally been suggested to be the syn Electron diffraction s t~d i e s~,~ seemed to favor a nonplanar gauche structure as the next most stable conformer, the angle @ lying in the range 1 16-123'.…”

Section: ( 8 )mentioning

confidence: 95%

“…However, a further refinement favored the existence of a gauche form { = 116 ± 7°) as the second stable conformer. Most recently, photoelectron spectra of methyl vinyl sulfide have been recorded over the range of temperature 20-600 °C by Müller et al 6 They have confirmed the existence of a gauche form as the second stable isomer.…”

mentioning

confidence: 94%

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Ab initio study of the conformations of vinyl mercaptan, methyl vinyl sulfide, and methyl allenyl sulfide

Kao¹

1978

J. Am. Chem. Soc.

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Ab initio (STO-3G and 44-3 lG) molecular orbital theory has been employed to investigate the rotational potential surfaces of methyl mercaptan, methyl vinyl sulfide, and methyl allenyl sulfide. Both STO-3G and 44-31G predict, for internal rotation along the CS,2-S bond, two stable conformations and the syn is the more stable one. However, for each molecule, a gauche form is found as the second stable conformation by 44-3 lG, as opposed to the anti by STO-3G. The corresponding rotational barriers predicted by STO-3G are apparently too high, while those by 44-31G are reasonable. The rotational barrier for a methyl group has also been studied for the syn and anti conformations of methyl vinyl sulfide and methyl allenyl sulfide. The methyl rotational barrier (STO-3G) for the syn is much larger in methyl vinyl sulfide (3.1 kcal mol-') than in methyl allenyl sulfide (1.9 kcal mol-') presumably due to steric interactions. Structural variations and conformational energies are rationalized in terms of orbital and steric interactions.

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Section: Discussionmentioning

confidence: 99%

Section: ( 8 )mentioning

confidence: 95%

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Ab initio study of the conformations of vinyl mercaptan, methyl vinyl sulfide, and methyl allenyl sulfide

Kao¹

1978

J. Am. Chem. Soc.

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“…79 The extent of isomerisation of a cisrotamer of methyl vinyl sulfide into the gauche-rotamer at 200 ± 600 8C is 20%. 80…”

Section: Dialkyl Sulfides and Their Derivativesmentioning

confidence: 99%

Thermal transformations of organic compounds of divalent sulfur

Воронков¹,

Deryagina²

2000

Russ. Chem. Rev.

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“…It was our desire to continue this initial work by using the variable temperature method, recently used by two of us (5). It has been previously used with success for studying conformational problems (6)(7)(8)(9)(10).…”

Section: Introductionmentioning

confidence: 99%

Tautomerism of pyrazoline-5-thione and triazoline-5-thione studied by variable temperature photoelectron spectroscopy

Guímon¹,

Pfister‐Guillouzo²,

Begtrup³

1983

Can. J. Chem.

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CLAUDE GUIMON, GENEVIEVE PFISTER-GUILLOUZO, and MIKAEL BEGTRUP. Can. J. Chem. 61, 1197 (1983.Photoelectron spectra at variable temperatures demonstrate that the rate of thermal isomerization of pyrazoline-5-thione ( l a ) into methylthiopyrazolc(s) in the gaseous phase is mctal catalysed. Similar isomerizations of triazolethione (20 and 30) are at best only slightly so.Furthermore, photoelectron spectra and MNDO calculations show that gaseous methylthiopyrazoles (16 and l c ) and mcthylthiotriazolcs (26 and 2c) exist predominantly in planar form for the 6 isomer and in nonplanar form for the c isomer. The AH" for the rotameric equilibria is 2.7-4.2 kJ.mol-'. CLAUDE GUIMON, GENEVIEVE PFISTER-GUILLOUZO et MIKAEL BEGTRUP. Can. J. Chem. 61, 1197Chem. 61, (1983. L'analysc des spectres photoelectroniques enregistrts a I'aide d'une "sonde i ternptrature variable" montre que la transformation en phase vapeur de la pyrazoline-thione-5 ( l a ) en mtthylthio-pyrazole(s) est catalysie par les parois metalliques de la sonde. Cette rtaction d'isomerisation est, semblc-t-il, nettement plus difficile dans le cas des triazolethiones (20 et 30).D'autre part les spectres exptrimentaux et les calculs thtoriques rtalists I'aide de la mtthode MNDO montrent que les composts S-mtthylks ( l b , l c , 26 et 2c) existent prtfkrentiellement sous une forme plane dans le cas des isomkres 6 et une forme non plane dans celui des isornkres c et qu'ils prtsentent un tquilibre entre rotameres (AH" cornpris entre 2.7 et 4.2 kJ. mol-I).

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Theory and application of photoelectron spectroscopy. 61. Detection of rotational isomers by variable temperature photoelectron spectroscopy. A new technique in the realm of molecular conformational analysis

Cited by 54 publications

References 3 publications

Ab initio study of the conformations of vinyl mercaptan, methyl vinyl sulfide, and methyl allenyl sulfide

Ab initio study of the conformations of vinyl mercaptan, methyl vinyl sulfide, and methyl allenyl sulfide

Thermal transformations of organic compounds of divalent sulfur

Tautomerism of pyrazoline-5-thione and triazoline-5-thione studied by variable temperature photoelectron spectroscopy

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