Some Comments on the Conformations of Methyl Phenyl Sulfides, Sulfoxides and Sulfones

Abstract

Summary13C-NMR. and He (Ia) photoelectron spectra of alkyl phenyl sulfides, sulfoxides and sulfones have been used to probe how their conformations depend on the size of the alkyl groups R. The results are interpreted to indicate that in the sulfides the S,R-bond is twisted out of the planar conformation with increasing size of the alkyl group, whereas in the sulfoxides and sulfones the preferred conformation with the S,R-bond perpendicular to the phenyl group plane seems to be independent of the size of R. These conclusions are in agreement with previous work on the alkyl phenyl sulfides and provide strong support for previous conjectures concerning the preferred conformations of alkyl phenyl sulfoxides and sulfones.In this work we report the I3C-NMR. spectra of the alkyl phenyl sulfides l(R), sulfoxides 2(R) and 3(R), sulfones 4(R), as well as the He(1a) photoelectron spectra of 2 (R), 3 (R) and 4 (R). (R)The aim of the investigation was to derive spectroscopic information concerning the dependence of the phenyl-sulfur C,S-bond twist angle p on the size of the alkyl group R. In compounds such as 1(R) to 4(R) the angle p is a function of mainly two effects: a) the angular dependence of the conjugation of the functional group with the phenyl ring, and b) the steric interference of R with the ortho positioned H-atoms and/or the electron cloud of the phenyl group n-system.

An ab initio Quantum-Chemical Study of C6H5S(O)CH3 and C6H5S(O)CF3

“…Wehry [35] showed that the steric interactions (introduction of o-CH 3 groups) only weakly affect the s constants of the S(O)CH 3 group, suggesting stable conformation of methyl aryl sulfoxides. The same conclusion follows from the photoelectron [17] and 13 C NMR [17,22] spectra of alkyl phenyl sulfoxides (Alk = Me, Et, i-Pr, t-Bu). Analysis of the Kerr constants shows that the methyl group in C 6 H 5 S(O)CH 3 is turned relative to the benzene ring plane by 70o + 5o [24,36].…”

“…As shown in [28333], the S=O groups are approximately coplanar to the phenyl rings to which they are bonded. For aryl methyl sulfoxides substituted in the ring, the same conclusion follows from the effects of shift reagents on the 13 C and 17 O NMR spectra [19], from the n J(HF) and n J(CF) coupling constants [20], from the low-temperature 1 H NMR spectra [34], and from the photoelectron spectra considered in combination with the 13 C NMR spectra [17]. Wehry [35] showed that the steric interactions (introduction of o-CH 3 groups) only weakly affect the s constants of the S(O)CH 3 group, suggesting stable conformation of methyl aryl sulfoxides.…”

“…); 0.67 [9, 10] (s I ); 0.13 [9,10] son with the corresponding s constants of other substituents, with the aim to explain or predict the reactivity of these compounds (see, e.g., [12314]). The compound C 6 H 5 S(O)CH 3 was studied by the methods of dipole moments [15], photoelectron spectroscopy [16 318], 1 H [19,20], 13 C [17,19322], and 17 O [19,20,23] NMR spectroscopy, X-ray emission spectroscopy [22], and Kerr constants [24]. The compound C 6 H 5 S(O)CF 3 was studied by the methods of dipole moments [25] and 19 F [26], 13 C [26,27], and 17 O [26] NMR spectroscopy.…”

Long-range coupling constants for α-13C nuclei in phenyl-X-R (X = O,S,Se,Te) derivatives. Internal rotational information

“…13C nuclear magnetic resonance and photoelectron studies (17,18) of alkyl phenyl sulfides (R = CH3, CH2CH3, C(CH3)3) demonstrate that the degree of nonplanarity increases monotonically as the size of the alkyl group increases (19). The degree of nonplanarity is a compromise between the effects of 3p.…”

UV spectra of substituted styrylarylsulphones

“…Опублікована низка праць присвячена дослідженню конфoрмацій вінілсульфонів залежно від природи радикалів, сполучених з сульфонільною групою [10,11]. Йдеться про можливість існування заміщених сульфонів як у гош-, так і в транс-конформаціях у бензольних розчинах [12,13].…”