Crystal Structure of Bis[O,O′-di(p-tolyl)thiophosphoryl]disulfide, [(p-MeC6H4O)2PS2]2

The structural chemistry of metal complexes with bis(thiophosphoryl) and bis(thiophosphinyl) disulfides has been extensively reviewed.1 The reactive –S–S– functional moiety determines the chemical properties of these thermally stable disulfides, and their photolytic properties are important in photochemically activated reactions. Bis(thiophosphoryl)disulfides act as potentially significant stabilizers for polymer composition, as vulcanization accelerators, and as antioxidants. These disulfides also act as antiwear additives in ash-less and extreme pressure engine lubricants, and are involved in the mechanism of the antioxidant action of metal dithiophosphate lubricant oil additives. Some bis(thiophosphoryl)disulfides show fungicidal activity. Due to the significance of the disulfide bond in natural products, the physiochemical properties of –S–S– linkages have been extensively studied over the last few decades. Molecular structures of several organothiophosphoryl disulfides have been determined, including [{(i-Pr)O}2PS2]2, [(PhO)2PS2]2, and [OCMe2CMe2OPS2]2 which provide for comparisons with the structure of bis[O,O¢-di(p-tolyl)thiophosphoryl]disulfide, [(p-MeC6H4O)2PS2]2. The title compound was prepared by a literature method.5 An orange block crystal of [(p-MeC6H4O)2PS2]2 was mounted in a capillary within a glove box, thus maintaining a dry, O2-free environment for each crystal. No statistically significant change over the duration of the data collection was observed. Experimental details and results are given in Table 1. All of the non-hydrogen atoms were treated anisotropically. Hydrogen atoms were included at idealized positions with isotropic thermal parameters. The distances and bond angles are given in Table 2. The ORTEP diagram in Fig. 2 shows the previously described2 essentially planar zigzag array of the S–P–S–S–P–S linkages X-ray Structure Analysis Online