P6S5(C4H9)2, THE 1ST ORGANOPHOSPHORUS CHALCOGEN MOLECULE WITH A BREXANE SKELETON

P6S5(C4H9)2, ,8lambda5-hexahosphatricyclo[4.3.0.0(3.7A)]nonane, M(r) = 460.40, monoclinic, P2(1)/c, a = 12.255 (17), b = 12.866 (14), c = 12 .522 (12) angstrom, beta = 100.53 (9)-degrees, V = 1941 (4) angstrom3, Z = 4, D(x) = 1.575 Mg m-3, Mo Kalpha, lambda = 0.71069 angstrom, mu = 1.048 mm-1, F(000) = 944, T = 295 K, R = 0.042 for 2226 observed uni que reflections. The molecule is the first P-S analogue of the tricycl ic brexane. It is formally obtained from a norbornane-structured P5S2 by addition,of a PS bridge. The bond angles and distances [for P-P 2.1 80 (2)-2.217 (2) angstrom, for endocyclic P-S 2.112 (2)-2.136 (2) angs trom, for exocyclic P-S 1.936 (3) and 1.941 (3) angstrom, and for P-C 1.846 (6) and 1.851 (6) angstrom] agree well with those of similar com pounds. P6S5(C4H9)2 is one of several products, obtained from reaction of P4S3 with tert-butyl iodide in CS2. Single crystals were obtained by fractional crystallization.