Table 1. Hydrogen-bond geometry (Å, °) for (I) .

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N8A—H8A⋯O11B	0.89 (2)	1.78 (2)	2.665 (2)	170 (2)
N4B—H41B⋯O11B i	0.89 (2)	2.05 (2)	2.939 (2)	176 (2)
N4B—H42B⋯O12B ii	0.92 (2)	1.98 (2)	2.891 (2)	176 (2)

Symmetry codes: (i) ; (ii) .