X-ray Diffraction, UV Photoelectron, and Ab Initio Study of Intramolecular Interactions in .beta.-Carbonyl Sulfones

Spectroscopic and theoretical studies of some N-methoxy-N-methyl-2-[(4′-substituted) phenylsulfonyl]propanamides

“…Table 5 presents selected NBO interactions and the occupancies for donor and acceptor orbitals for g 1 and g 2 conformers of compound 3 taken as representative for the whole series (1)(2)(3)(4)(5).…”

“…Previous spectroscopic (IR, 13 C NMR, UV and UPS), X-ray diffraction and theoretical studies from our laboratory on some b-carbonyl-sulfones YC(O)CH 2 SO 2 R (Y = Me, Ar, NR 2 , OR and SR; R = Me, Ar) [1][2][3][4][5][6][7] indicated that these compounds in gas phase, in solution and in the solid state prefer the gauche conformation between the C@O and CH 2 AS bonds with respect to the cis conformer, excepting the thioester-sulfones [6] for which only the gauche conformers are present both in gas phase and in solution.…”

Predominance of inductive over resonance substituent effect on33S NMR chemical shifts of 4-substituted phenyl-4′-methylphenacyl sulfones

“…4 The chemical shifts of methylene protons in the spectra ofˇ-keto sulfones ArCOCH 2 SO 2 C 6 H 4 R were found to be linearly dependent on and especially on C substituent constants. 4,13 Differing from the substituent effect on the pK a values of compounds of formula p-R 0 C 6 H 4 COCH 2 SO 2 C 6 H 4 R-p, 5 the 1 H NMR spectra show that the substituent effect is more effectively transmitted to the methylene protons from R 0 than from R. 13 X-ray diffraction 14,15 and photoelectron spectral studies 14 and ab initio calculations 14 show that there are some interesting non-bonded interactions inˇ-keto sulfones that may affect transmission of the substituent effect in these compounds. Thus, the oxygen atom of the SO 2 group points toward the oppositely charged carbonyl carbon atom, from which it is separated by a distance shorter than the sum of their van der Waals radii.…”

“…The O C O -S distance is not as critically short as that between O SO 2 and C C O . 14 Generally, there is a great need for NMR information on sulfur because of the importance of this element in chemistry and biochemistry. 16,17 To our knowledge, 33 S NMR spectroscopy has not been used before in studies of -keto sulfones.…”

Conformational and electronic interaction studies of some p-substituted α-methylsulfonyl-α-diethoxyphosphorylacetophenones

“…Previous spectroscopic (IR, 13 C NMR, UV and UPS), X-ray diffraction and theoretical studies of b-carbonyl-sulfones XC(O)CH 2 SO 2 R (X = Me, Ar, NR 0 2 , OR 0 and SR 0 (Ar); R = Me, Et, Ar) indicated that these compounds, in the gas phase, solution and in the solid state prefer the gauche conformation between the C@O and C-S bonds [1][2][3][4][5][6]. The stabilisation of the gauche rotamers of b-carbonyl-sulfones has been ascribed to p * CO /r C-S and p CO /r * C-S orbital interactions, along with crossed electrostatic and charge transfer interactions between oppositely charged atoms, i.e.…”