Bond distances carbon-sulfur

The significance of these results for differences in reactivities of nucleophiles is that, despite the unfavorable relative equilibrium constants, Me2S is more reactive toward the quinone methide than chloride ion by a factor of nearly 3000. This mismatch of rate and equilibrium effects is summarized in Scheme 35. It must imply (a) that there is a relatively long partial bond between sulfur and carbon in the transition state so that the unfavorable steric and electrostatic effects are not developed and (b) that the favorable carbon-sulfur bonding interaction is well developed despite the long bonding distance. 

Reaction of a stable carbene with sulfuric chloride results in abstraction of the chloride cation to give the adduct 48 (Scheme 27).57 The C2 carbon resonates at 133.05 ppm in the 13C NMR spectrum and the solid state structure exhibits a chlorine-NHC bond distance of 1.696(9) A. The fluor-ine-NHC analogue was prepared by Kuhn and co-workers by reaction of the stable carbene with S02F2.50 The solid state structure exhibits a fluorine-NHC bond distance of 1.291(14) A. 

This equation can be solved by estimating De as one-half the bond distance either of a C=C bond if an sp2 carbon is bridging (De = 0.669 A), or of S2 if an sp2 sulfur atom is bridging (De = 0.994 A). The calculated values of a when added to the angle L—Cur—X provide an estimate for the interorbital angle y which reflects the coordination geometry of copper. 

Bond distances and angles are similar to those observed for the related phenyl- and phenylene-substituted compounds described previously (Sections V.A, XV, and XXII.C). The solvent molecule interacts weakly with the 1,2,3,5-dithiadiazolylium heterocyclic ring, but it does not appear to induce any significant structural perturbations. As with other 1,2,3,5- and 1,3,2,4-dithiadiazolylium salts, weak anion-cation interactions are seen between fluorine and both carbon and sulfur, but not between fluorine... 

Bent also mentions the packing of triketoindane [6], which shows short inter-molecular distances between carbonyl oxygen and carbon atoms (Figure 5.2). In the language of organic chemistry, this is an interaction between a nucleophilic oxygen and an electrophilic carbon atom. A later study of the environments of divalent sulfur (Y-S-Z) in crystals showed the shortest non-bonded contacts between sulfur... 

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