Crystal structure and Hirshfeld surface analysis of 3,3'-(sulfanedi-yl)bis-(2-iodo-1-methyl-1H-indole).

The title compound, C18H14I2N2S, comprises two N-methyl-2-iodo-indole fragments linked at the 3-positions by a thio-ether bridge. The sulfur atom adopts a typical thio-ether geometry, and the C-S-C linkage is gauche on both sides, with C-S-C-C torsion angles of -64.1 (11) and -48.3 (10)°. The indole units are essentially planar and are strongly inclined to one another, with an inter-planar angle of 103.3 (3)°. The compound crystallizes in the ortho-rhom-bic space group Fdd2; the mol-ecule lacks classical hydrogen-bond donors, and no significant hydrogen bonding or π-π stacking is observed. The packing is dominated by van der Waals inter-actions together with short I⋯C and I⋯π contacts, giving a herringbone arrangement and forming chains along the b axis. Hirshfeld surface analysis indicates that H⋯H (33.1%), H⋯C/C⋯H (25.5%) and H⋯I/I⋯H (24.4%) contacts make the largest contributions to the crystal packing.