Figure 1
The molecular structures of (a) (I) and (b) (II), showing the atom-labelling schemes. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. [Symmetry codes: (i) −x, y, −z + ; (ii) −x, −y + 1, z; (iii) −x + , y, z.] |