Hirshfeld surface analysis of the 1,1'-(ethane-1,2-diyl)dipyridinium dication in two new salts: perchlorate and peroxodisulfate.

In the title salts, C12H14N2(2+)·2ClO4(-), (I), and C12H14N2(2+)·S2O8(2-), (II), the dication is organized around an inversion centre located at the centre of the -CH2CH2- bridge and the two pyridine segments are anti with respect to one another. The peroxodisulfate anion in (II) also exhibits inversion symmetry. Hirshfeld surface analysis shows closely similar Hirshfeld surface shapes for the dications in the two salts, reflecting similar intermolecular contacts and similar conformations. The two-dimensional fingerprint plots (FPs) are quite asymmetric, due to the presence of more than one component (cation and anion). The most striking of the complementary features for each of the FPs of the dications is the broad green spike in the region d(e) > d(i), without the presence of a corresponding spike in the region d(e) < d(i), reflecting the absence of O···H contacts. Moreover, H···O interactions (51% in the dications of both salts) outnumber other contacts in both crystal structures.