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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N4—H4N⋯O6	0.88 (2)	1.97 (2)	2.849 (2)	171.9 (19)
N3—H3N⋯N6	0.83 (2)	2.00 (2)	2.705 (2)	141.8 (19)
O6—H6A⋯O3i	0.82 (4)	2.32 (4)	3.119 (3)	168 (4)
O6—H6B⋯O2ii	0.73 (4)	2.44 (4)	3.143 (3)	164 (4)
O6—H6B⋯O1ii	0.73 (4)	2.62 (4)	3.248 (3)	146 (4)

Symmetry codes: (i) ; (ii) .