Synthesis and characterisation of <i>tris</i> (2,4-xylyl)phosphane oxide and the heavier chalcogen derivatives of <i>tris</i> (2,4-xylyl)- and <i>tris</i> (3,5-xylyl)phosphane

The synthesis and characterisation of the novel sulfide and selenide adducts of both tris(2,4-xylyl)phosphane (i.e., 1; S adduct: 3; Se material: 4) and tris(3,5-xylyl)phosphane (5) are reported (S: 7; Se: 8) in addition to the previously unknown oxide of 1 (viz., 2). The heavier group 16 (Selenium) compounds 4 and 8 were produced by a rarely used photochemical protocol employing dialkyldiselenides as the Se source. Attempts to obtain the elusive selenide complex of trimesitylphosphane (9: i.e., tris(2,4,6-trimethylphenyl)phosphane) by this and other previously untried methods is also detailed but were ultimately unsuccessful. These observations further support the surmised instability and/or inaccessible nature of the selenide adduct of 9. Crystals of both 3 and 4 were obtained in the monoclinic P2 1 / c space group each with two unique molecules in the unit cell; the 3,5-congeners 7 and 8 are found in the trigonal R3 c space group. Compound 2 was found to crystallize in space group C2/c. The isolated and examined crystalline material obtained from bulk 8 is found to contain 81.0% of the phosphane-selenide with the residual lattice sites being occupied by selenide-free 5. The solid-state structural aspects of the examples reported herein are discussed and are placed into context with other (aryl) 3 P=E (E = O, S, or Se) materials.