Marek J. Potrzebowski, Jarosław BŁaszczyk, Michał W. Wieczorek, Konrad Misiura and Wojciech J. Stec
31P and 77Se high resolution solid state NMR
spectroscopy was employed to study structural properties of
2-N,N-diisopropylamino-1,3,2λ5-
oxaselenaphospholane-2-selone 5 the compound made in the course of
developing reagents for stereocontrolled synthesis of
nucleoside–phosphorothioates. Both 31P CP/MAS and
77Se CP/MAS experiments revealed that the asymmetric unit
consists of two independent molecules with different geometry around
phosphorus and selenium centres. The principal elements
δii of the 31P chemical shift tensor
were calculated from spinning sideband intensities employing the WIN-MAS
program. The established values of anisotropy and asymmetry parameters
reflect the distortion of the phosphorus environment and correspond well
with X-ray diffraction data. Crystals of
2-N,N-diisopropylamino-1,3,2λ5-
oxaselenaphospholane-2-selone grown from diethyl ether are triclinic, space
group P with a = 7.586(2),
b = 13.003(1), c = 13.649(1)
Å, α = 89.683(8)°,
β = 75.42(1)°, γ = 8.74(1)°,
V = 1285(6) Å3,
Dc = 1.722(2) g cm-3 and
Z = 4. Refinement using 5243 reflections for 235
variables gives R = 0.047.