Preparation and X-ray crystal structures of the first radical cation salts of 4-iodotetrathiafulvalene: [ITTF.+](2)center dot{Pd[S2C2(CN)(2)](2)}(2-) and (ITTFHSO4-)-H-.+

The title radical ion salts of 4-iodotetrathiafulvalene 1 have been prepared and their X-ray crystal structures determined at 150 K. The 2 : 1 salt [ITTF .(+)](2) .{Pd[S2C2(CN)(2)](2)}(2-) 3 forms a mixed stack structure in which the Pd(mnt)(2) anions intermingle with pairs of iodo-TTF radical cations, i.e. a DDADDA stacking arrangement. The structure of the 1 : 1 saltITTF .(+) HSO(4)(-)4 comprises stepped slacks of ITTF cations with two alternating modes of overlap. Between the cation stacks there are infinite chains of hydrogensulfate anions, linked by hydrogen bonds. Both structures are characterised by short intermolecular contacts involving the iodine substituent.