The crystal structures, Hirshfeld surface analyses and energy frameworks of two hexa­thia­pyrazino­phane regioisomers; 2,5,8,11,14,17-hexa­thia-[9.9](2,6,3,5)-pyrazino­phane and 2,5,8,11,14,17-hexa­thia-[9.9](2,5,3,6)-pyrazino­phane

The title thia­pyrazino­phanes, 2,5,8,11,14,17-hexa­thia-[9.9](2,6,3,5)-pyrazino­phane, C16H24N2S6, (I), and 2,5,8,11,14,17-hexa­thia-[9.9](2,5,3,6)-pyrazino­phane, C16H24N2S6, (II), are regioisomers; m-bis L1 and p-bis L1, respectively. Both compounds have a central tetra-2,3,5,6-methyl­ene­pyrazine unit with two –S—CH2—CH2—S—CH2—CH2—S– chains, linking the methyl­ene C atoms at positions 2 and 6 and 3 and 5 on the pyrazine ring of I, but linking the methyl­ene C atoms at positions 2 and 5 and 3 and 6 on the pyrazine ring of II. Both compounds crystallize with half a mol­ecule in the asymmetric unit. The whole mol­ecule of I is generated by inversion symmetry, with the pyrazine ring being located about a center of symmetry. The whole mol­ecule of II is generated by twofold rotation symmetry, with the pyrazine N atoms being located on the twofold rotation axis. In compound I, there are pairs of intra­molecular C—H⋯S contacts present, but none in compound II. In the crystal of I, there are no significant inter­molecular inter­actions present, while in the crystal of II, mol­ecules are linked by pairs of C—H⋯S hydrogen bonds, forming corrugated layers lying parallel the ac plane. The Hirshfeld surfaces and the energy frameworks of the two regioisomers indicate little difference in the inter­atomic contacts, which are dominated by dispersion forces.