5,6,7,8-Tetrahydro-2,3-diphenyl-2aλ⁴-thia-2,3,4a,8a-tetraazacyclopent[cd]azulene-1[2H],4[3H]-diselone

The title compound, C₁₉H₁₈N₄SSe₂, crystallizes in the P space group with two molecules in the asymmetric unit. In both molecules the chemically equivalent halves are identical within experimental error, except for conformational differences which arise from intermolecular interactions between the flexible seven-membered rings and surrounding selenium atoms. The central triheterapentalene system is almost planar, with individual ring conformations consistent with three regions of conjugation separated by single bonds. The N-S bond lengths, stretched beyond the standard for a single bond, imply a three-centre interaction.

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