Crystal structures of two bis­(iodo­meth­yl)benzene derivatives: similarities and differences in the crystal packing

The isomeric derivatives 1,2-bis­(iodo­meth­yl)benzene, (I), and 1,3-bis­(iodo­meth­yl)benzene (II), both C(8)H(8)I(2), were prepared by metathesis from their di­bromo analogues. The ortho-derivative, (I), lies about a crystallographic twofold axis that bis­ects the C—C bond between the two iodo­methyl substituents. The packing in (I) relies solely on C—H⋯I hydrogen bonds supported by weak parallel slipped π–π stacking inter­actions [inter-centroid distance = 4.0569 (11) Å, inter-planar distance = 3.3789 (8) Å and slippage = 2.245 Å]. While C—H⋯I hydrogen bonds are also found in the packing of (II), type II, I⋯I halogen bonds [I⋯I = 3.8662 (2) Å] and C—H⋯π contacts feature prominently in stabilizing the three-dimensional structure.