Phenylene trithiocarbonate

Explicitly included are species with carbonyl (>CO) groups such as the isomeric phthalimide (VIII) and isatin (IX), and with thiocarbonyl (>CS) groups such as the isomeric benzo-l,2-dithol-3-thione (X) and benzo-l,3-dithiol-2-thione (phenylene trithiocarbonate) (XI). Conversely, species with the isoelectronic >BF (and the related >BH) are ignored. Thus the question of the aromaticity in carboranes never arises in this chapter, even had we been explicitly interested in three-dimensional aromaticity (another issue we will ignore here). 

Finally, we turn to sulfur-containing species. Many indane derivatives may be suggested. However, there are only a few for which the enthalpy of formation has been determined phenylene trithiocarbonate (benzo-l,3-dithiole-2-thione) (X = Z = S, Y = CS) (XI), the isomeric benzo-l,2-dithiole-3-thione (X = Y = S, Z = CS) (X) [50],... 

This reaction is essentially thermoneutral. Although we lack enthalpy of formation data for the corresponding 1,3-benzodithiole, the weakness of 1,3 sulfur-sulfur interactions as manifest by the near equality [52] of the enthalpies of formation of 1,3- and 1,4-dithiane (unlike 1,3- and 1,4-dioxane) suggests no special interaction in this nonaromatic heterocycle. Said differently, the thermoneutrality of the above reaction, as opposed to profound exothermicity (21 kJ mol ) for indane (six n electrons) and the endothermicity (29 kJ mol1) for benzimidazolinone (ten n electrons), suggests phenylene trithiocarbonate (ten n electrons) has an intermediate degree of aromaticity. For the latter two species, analysis of the related reactions ... 

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