X-ray crystallograA single crystal was carefully selected under polarizing microscope in order to perform its structural analysis by X-ray diffraction. Diffraction data were collected on a Nonius Kappa
diffractometer equipped with a CCD detector with graphitemonochromatized Mo Ka radiation (k = 0.71069 Å). Intensities were
corrected for Lorentz, polarization and absorption effects [7]. The
structure was solved by direct methods with the SIR97 suite of
programs [8] and refinement were performed on F2 by full-matrix
least-squares methods with all non-hydrogen atoms anisotropic.
Hydrogens were included on calculated positions, riding on their
carrier atoms, apart from those linked to O, located in difference
Fourier map, whose coordinates were kept fixed. All calculations
were performed using SHELXL-97 [9] implemented in the WINGX
system of programs [10]. The crystal data are reported in Table 1.
The drawings were made with Diamond [11] and ORTEPIII [12].phic study