Crystal structures of bis[2-(diphenylphosphinothio-yl)phenyl] ether and bis{2-[diphenyl(selanylidene)-phosphanyl] phenyl} ether

The title compounds, C36H28OP2S2, ( 1), and C36H28OP2Se2, (2), exhibit remarkably similar structures although they are not isomorphous. The whole molecule of compound (2) is generated by twofold symmetry, with the ether O atom located on the twofold axis. Both compounds have intramolecular pi-pi interactions between terminal phenyl rings with centroid-centroid distances of 3.6214 (16) and 3.8027 (14) angstrom in (1) and (2), respectively. In the crystal of (1), short C-H center dot center dot center dot S hydrogen bonds link the molecules, forming chains along [001], while in ( 2) there are no analogous C-H center dot center dot center dot Se interactions present.