CRYSTAL AND MOLECULAR STRUCTURE OF 2,10 DICHLORO 6-TRICHLOROMETHYLDIBENZO [d,g] [1,3,6,2] DIOXATHIAPHOSPHOCIN 6-OXIDE. N. Jagadeesh Kumar, T. V. Narasaiah, M. Krishnaiah, Department of Physics, Sri Venkateswara University, Tirupati-517 502, INDIA
The crystal structures and conformations of organophosphorus compounds have become the subject of intense study due to their involvement in many biological processes(Corbridge, 1977; Emsley & Hall, 1976 and Sankara Reddy & Devendranath Reddy, 1995). To our knowledge there have been few reports on structural studies of 8-membered heterocyclic organophosphorus compounds with sulfur as one of the endocyclic atoms which prompted us to undertake the crystal structure determination of [1,3,6,2] dioxathiaphosphocin derives to know their molecular and conformational change with respect to the different oxocyclic substituents.
Crystals of title compound obtained from 2-propanol are colourless, monoclinic, P21/n with a=11.624(7), b=11.091(3), c=14.407(4)Å, [[beta]]=107.88(3)deg., v=1767.7(12)Å3, Z=4,[[rho]]c =1.693Mg/cm3, [[lambda]]=0.71073Å, u(MoK[[alpha]])=10.37cm-1. The structure has been solved by direct methods (SHELXS 86) using 2652 reflections measured at room temperature on a CAD-4 diffractometer. The refinement by full matrix least-squares method using SHELXL-93 lowered the disagreement factor as R=0.0451 and Rw=0.1093 for 2525 significant reflections [I>=2[[sigma]](I)].
The dioxathiaphosphocin ring exhibits a distorted boat conformation which is differing from the expected BC form other similar structures( Mani Naidu et al., 1992, 1994 & 1996).