THE SYNTHESIS, X-RAY AND SOLID-STATE NMR-STUDIES OF MINO-1,3,2-LAMBDA(5)-OXASELENAPHOSPHOLANE-2-SELONE

P-31 and Se-77 high resolution solid state NMR spectroscopy was employ ed to study structural properties of 2-N,N-diisopropylamino-1,3,2 lamb da(5)-oxaselenaphospholane-2-selone 5 the compound made in the course of developing reagents for stereocontrolled synthesis of nucleoside-ph osphorothioates. Both P-31 CP/MAS and Se-77 CP/MAS experiments reveale d that the asymmetric unit consists of two independent molecules with different geometry around phosphorus and selenium centres, The princip al elements delta(ii) of the P-31 chemical shift tensor were calculate d from spinning sideband intensities employing the WIN-MAS program, Th e established values of anisotropy and asymmetry parameters reflect th e distortion of the phosphorus environment and correspond well with X- ray diffraction data, Crystals of 2-N,N-diisopropylamino-1,3,2 lambda( 5)-oxaselenaphospholane-2-selone grown from diethyl ether are triclini c, space group <P(1)over bar> with a = 7.586(2), b = 13.003(1), c = 13 .649(1) Angstrom, alpha = 89.683(8)degrees, beta = 75.42(1)degrees, ga mma = 8.74(1)degrees, V = 1285(6) Angstrom(3), D-c = 1.722(2) g cm(-3) and Z = 4. Refinement using 5243 reflections for 235 variables gives R = 0.047.