Structure of phenacyl phenyl sulfone

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

“…C and O ! S interactions inˇ-keto sulfones 14,15 result in the 33 S chemical shift being only slightly dependent on the substituent. Low-quality linear dependences were found between these chemical shifts and substituent constants.…”

“…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.…”