“…[74] Thesame effect was seen when comparing the iminocyclohexadienylidenes and the oxocyclohexadienylidenes,w here the latter largely retain their C=Ob onds (Figures 1a nd 2). Tr iplet thioacylnitrenes are not known, but their calculated spin densities [91] and comparison with known carbenes indicate they should be delocalized 1,3diradicals with very low D values similar to vinylnitrenes.A C=Sg roup is much more prone than C=Ot od elocalize an electron and thus diminish its double-bond character.Closedshell singlet thioacylnitrenes are stabilized by as trong S À N interaction that gives them ahigh degree of three-membered thiazirine ring structure, [92] although the reaction with DMSO suggests partial nitrenoid character of thiobenzoylnitrene. [91] Vinylnitrenes have very low D values on the order of 0.4 and significant spin densities on the vinylic carbon atoms (see compounds 100, 103, 105, 107,and 109 in Figure 5, Scheme 19, and Table S1).…”