Figure 2
The hydrogen-bond pattern (dashed lines) in the structure of (I), showing the directed four-membered co-operative hydrogen bonds. H atoms not involved in the hydrogen-bonding pattern have been omitted for clarity. [Symmetry codes: (ii) −x + , −y + , z + ; (iv) 1 − x, −y, 1 − z; (v) x + , y − , −z + .] |